the diagnostic value of left-anterior-descending artery velocity assessed by transthoracic Doppler echocardiography for microvascular dysfunction in stenotic left-anterior-descending artery

Background

Index of microcirculatory resistance (IMR) has been used as a clinical measure of microvascular function. Transthoracic Doppler echocardiography (TDE) can provide information on the functional status of coronary artery circulation. This study aims to assess the diagnostic value of left-anterior-descending artery (LAD) flow velocity by TDE for microvascular dysfunction.

Methods

Consecutive patients who were scheduled for elective percutaneous coronary intervention (PCI) for LAD lesions were prospectively enrolled in the single tertiary-care center between April 2020 and July 2021. Pre-PCI LAD diastolic peak velocity (DPV) by TDE at rest and hyperemia were measured. By invasive coronary angiography, quantitative coronary angiography and invasive wire-based physiological indices including fractional flow reserve (FFR) and index of microcirculatory resistance (IMR) were measured.

Results

A total of 104 patients were studied. Median FFR and IMR values were 0.70 (0.60–0.74) and 20.68 (14.92–31.69), respectively. No significant relationship was observed between FFR and IMR. The prevalence of microvascular dysfunction defined as IMR≥25 was 39.4%. Basal DPV was 25 (20–33) cm/sec, and hyperemic DPV was 51 (41–67) cm/sec. In lesions with IMR≥25, reference diameter (RD) was significantly greater [2.63 (2.22–3.19) mm vs 2.39 (2.09–2.66) mm, p=0.019], basal DPV was lower [26 (18–29) cm/sec vs 29 (22–37) cm/sec, p=0.022)] and hyperemic DPV was lower [49 (19–54) cm/sec vs 56 (42–70) cm/sec, p=0.023] compared to lesions with IMR<25. ROC analysis showed basal DPV and RD are significant predictors of IMR≥25 [basal DPV: AUC 0.633 (0.525–0.742), best cutoff 29cm/sec RD: AUC 0.636 (0.523–0.750), best cutoff 2.84mm]. Multivariable logistic regression analysis showed basal DPV<29cm/sec and RD>2.84mm are independent predictors for IMR≥25 [Odds ratio: 3.08 (1.22–7.78), p=0.017; odds ratio 4.40 (1.55–12.50), p=0.005].

Conclusion

Basal DPV by non-invasive pre-PCI TDE and reference diameter can predict lesions with coexisting microvascular dysfunction in LAD territory with functionally significant lesions without the need of vasodilator-induced hyperemia and a wire-based invasive physiological measurement.

Funding Acknowledgement

Type of funding sources: None.

Identification of coronary plaque rupture or erosion by preprocedural computed tomography angiography in patients with non-st-segment elevation acute coronary syndrome

Background

The frequent pathological cause of acute coronary thrombosis is plaque rupture or erosion. A previous CT angiographic study failed to discriminate OCT-defined intact fibrous cap culprit lesions (IFC lesions) from those with ruptured fibrous cap (RFC group) in patients with acute coronary syndrome (ACS) and chronic coronary syndrome.

Objectives

This study aimed to evaluate the diagnostic efficacy of preprocedural coronary CT imaging to identify optical coherence tomography (OCT)-defined plaque rupture or erosion at culprit lesions in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS).

Methods

Consecutive patients with suspected NSTE-ACS who underwent preprocedural non-contrast CT and CT angiography (CCTA) were studied. Patients with at least one lesion with more than 50% stenosis at the proximal segment on CCTA were subsequently assessed by invasive coronary angiography and OCT. ALL CT and OCT examination were performed within 24 hours from presentation. The diagnosis of intact fibrous cap or ruptured fibrous cap was made by OCT for the angiographically most severely stenosed lesion. Cases of ambiguous OCT diagnosis such as massive thrombosis or calcified nodule precluding the fibrous cap assessment were excluded from the final analysis.

Results

In the final analysis of 176 patients, OCT identified 87 RFC plaques and 89 IFC plaques for the culprit lesions, respectively. In IFC group, lower prevalence of diabetes mellitus (24.7% vs. 41.4%, P=0.025) and lower peak cardiac marker elevation (CPK, 159 vs. 272 U/L, P<0.001) were observed. On CT, the prevalence of low attenuation plaque, positive remodeling, napkin ring sign, spotty calcification, calcium score (CAC), and culprit vessel pericoronary adipose tissue attenuation (FAI) were all significantly low in IFC group. Multivariate regression analysis to predict IFC at culprit lesions revealed that the absence of low attenuation plaque, the absence of napkin ring sign, zero CAC, and low FAI were independent predictors of IFC. When stratified by the number of these 4 CT factors, the presence of IFC were stratified as 0%, 23.6%, 50%, 77.8%, and 100% (P<0.001), respectively. Adding non-contrast CT factor of zero CAC to the reference model including age, sex, DM, EF, low attenuation plaque, napkin ring sign, and FAI, can increase the incremental discriminatory and reclassification performance for the prediction of IFC (C-statistic 0.828 NRI: 0.37, 95% CI: 0.095–0.646, P=0.008 and IDI: 0.042, 95% CI: 0.012–0.071, P=0.005).

Conclusions

Preprocedural comprehensive CT imaging including CAC and pericoronary adipose tissue inflammation could identify IFC or RFC culprit lesions defined by OCT. Further studies are needed to confirm our preliminary results and if CT imaging in NSTE-ACS provides prognostic information or specific therapeutic approach such as conservative therapy or non-stenting strategy before invasive angiography.

Funding Acknowledgement

Type of funding sources: None.

Diagnostic value of computed tomography myocardial perfusion to detect coexisting microvascular dysfunction in patients with obstructive epicardial coronary disease

Background

The usefulness of computed tomography myocardial perfusion (CTP) to assess hemodynamically significant epicardial coronary artery lesions has been previously reported. However, the diagnostic value of quantitative evaluation of absolute coronary flow by CTP to detect microvascular dysfunction remains unknown.

Purpose

The aim of study is to assess the diagnostic value of CTP to evaluate coronary microvascular dysfunction (CMD) in patients with significant epicardial coronary stenosis, and to analyze the predicting factors for lesions with CMD.

Methods

Sixty-eight chronic coronary syndrome patients with de novo single functionally significant stenosis (Fractional flow reserve [FFR] <0.80) were investigated. CMD was defined by the index of microcirculatory resistance (IMR) ≥25. Clinical characteristics and CTP findings were compared between the two groups with and without CMD (CMD, n=29, non-CMD, n=39, respectively). The computed tomography angiography (CCTA) assessment included CTP findings and quantitative and qualitative assessment of plaques.

Results

In wire-based analysis, FFR, coronary flow reserve (CFRwire) and IMR were 0.68 (0.59–0.74), 1.71 (1.24–2.88), and 22.6 (15.1–34.5), respectively.

In CTP analysis, culprit territory regional absolute myocardial blood flow (MBF) at rest (rest-MBF) and hyperemia (hyperemic-MBF) were evaluated semi-automatically. CTP-derived CFR (CFRCTP) was calculated as hyperemic-MBF divided by rest-MBF. Rest and hyperemic-MBF and CFRCTP were 0.83 (0.64–1.03) ml/min/g, 2.14 (1.30–2.92) ml/min/g, and 2.19 (1.44–3.37).

In the lesions with CMD, hyperemic-MBF was significantly lower than those without CMD (1.68 [0.84–2.44] vs 2.31 [1.67–3.34] ml/min/g, p=0.015) and the prevalence of CFRCTP<2.0 was higher in the lesions with CMD than those without CMD (62.1% vs 28.2%, p=0.007).

CCTA analysis showed that fibrofatty and necrotic core component (FFNC) volume was greater in the lesions with CMD than in the lesions without CMD (31.8 [19.0–48.9] vs 25.1 [17.2–32.1] mm3, p=0.045). The multivariable logistic regression analysis, hyperemic-MBF and FFNC volume were independent predictors for lesions with CMD (Odds ratio [OR] 0.583 [0.355–0.958], p=0.033 and OR 1.040 [1.010–1.070], p=0.018).

Conclusion

Quantitative assessment of absolute coronary flow by CTP and comprehensive plaque analysis by CCTA may help detect coexisting subtended microvascular dysfunction in patients with functionally significant epicardial coronary lesions. Further studies are needed to elucidate the clinical significance of coexisting CMD in CCS patients.

Funding Acknowledgement

Type of funding sources: None.

Contribution of dental health in cardiovascular secondary prevention

Backgrounds

Previous studies have suggested that periodontitis is associated with cardiovascular disease (CVD), partly through exaggerated systematic inflammation through pathogens breaking into the bloodstream and their metabolic products. However, the clinical evidence in the cardiovascular secondary prevention is limited. In addition, there is a paucity of data about the contribution of comprehensively assessed dental health, including dental caries or teeth loss, to CVD incidence. Consequently, current ESC guideline for CVD prevention just briefly refers the contribution of dental health [1].

Objective

To investigate the associations between teeth loss, periodontitis, and dental caries and incident major adverse cardiovascular events (MACE) in patients with existing CVD.

Methods

Patients with known CVD who were admitted to the Department of Cardiology between May 2012 and August 2015 were prospectively, consecutively enrolled. Patients underwent comprehensive dental examinations, including counts of lost teeth, dental caries, and periodontal measurements of clinical attachment loss (CAL), periodontal probing pocket depth (PPD), and bleeding on probing (BOP) by trained periodontists during the hospital stay. We assessed the associations between these dental measures and MACE, defined as a composite of cardiac death, acute myocardial infarction, stroke, and hospital re-admission for worsened congestive heart failure, using multivariate COX proportional hazard models and restricted mean survival time (RMST) analyses. P-values were adjusted by Bonferroni methods.

Results

Among 888 patients included for the present analyses, the mean age was 63.9 (SD: 13.1) years and there were 242 (27.3%) women. During a median follow-up of 4.6 (IQR: 1.4, 6.7) years, incident MACE was confirmed in 142 patients. In multivariate COX proportional hazard models, one more tooth loss was associated with 3 (95% CI: 1, 5) % higher hazard of MACE (adjusted p=0.020). Kaplan-Meier curves showing survival from MACE according to the quartiles of teeth loss were described in Figure 1. Compared with patients with 0 to ≤4 lost teeth, periods free from MACE (95% CI) by 5-years of follow-up were on average shorter by 0.17 (−0.04, 0.37) years, 0.26 (0.04, 0.49) years, and 0.59 (0.34, 0.85) years in patients with 5 to ≤7, 8 to ≤13, and >13 lost teeth, respectively. The RMST differences with varied cutoff years were shown in Figure 2. There were no significant associations between the number of dental caries, CAL, PPD, and BOP and MACE incidence.

Conclusion

In hospitalized patients due to existing cardiovascular diseases, total number of lost teeth was associated with incident MACE. Given that teeth loss is an ultimate consequence of periodontitis or dental caries, the present findings imply that efforts to prevent losing teeth by maintaining dental health would be effective measures for cardiovascular secondary prevention.

Funding Acknowledgement

Type of funding sources: None.

Multimodality coronary imaging to predict non-culprit territory unrecognized myocardial infarction assessed by cardiac magnetic resonance in non-ST-elevation acute coronary syndrome

Objectives

This study sought to assess the predictors of coherence tomography (OCT) and coronary computed tomography angiographic (CCTA) findings for non-infarct-related (non-IR) territory unrecognized myocardial infarction (UMI) in patients with first non-ST-elevation acute coronary syndrome (NSTE-ACS) presentation.

Background

UMI detected by cardiac magnetic resonance (CMR) is associated with adverse outcomes in patients with both acute coronary syndrome and chronic coronary syndrome. However, the association between the presence of UMI and findings of multimodality coronary imaging remains unknown.

Methods

We investigated 69 patients with a first clinical episode of NSTE-ACS, who underwent pre-PCI 320-slice CCTA, uncomplicated urgent percutaneous coronary intervention (PCI) with OCT assessment within 48 hours of admission, and post-PCI CMR. UMI was assessed on late gadolinium enhancement (LGE-CMR) by identifying regions of hyperenhancement with an ischemic distribution pattern in non-IR territories (non-IR UMI).

Results

Non-IR UMI was detected in 11 patients (15.9%). ROC analysis revealed the optimal cut-off value of PCATA in culprit vessel for predicting the presence of non-IR UMI were −71.3. Lower ejection fraction, higher Gensini score, high pericoronary inflammation (>−71.3), OCT-defined culprit lesion plaque rupture (OCT-PR), and OCT-defined culprit lesion cholesterol crystal (OCT-CC) were significantly associated with the presence of non-IR UMI (Figure 1A). OCT findings are shown in Figure 1B. Patients with non-IR UMI had a higher prevalence of OCT-PR and OCT-CC than those without. Compared with patients without non-IR UMI, the prevalence of high pericoronary inflammation was higher in patients with non-IR UMI (Figure 1C). When the total cohort was divided into four groups according to the numbers of aforementioned OCT-derived risk factors and PCATA, patients with all of these UMI risk factors showed 46.2% (6/13) prevalence of non-IR UMI, whereas none of 15 patients without these factors showed non-IR UMI (Figure 1D).

Conclusions

When culprit lesion showed OCT-PR, OCT-CC, and high PCATA, about half of these patients are likely to have non-IR UMI. The integrated CCTA and OCT assessment may help identify the presence of non-IR UMI, potentially providing prognostic information in first NSTE-ACS patients.

Funding Acknowledgement

Type of funding sources: None.

Cryoballoon ablation of left atrial roof with a novel cryoballoon system

Introduction

A novel cryoballoon system (POLARx) has emerged and its efficacy regarding pulmonary vein isolation (PVI) has been already investigated. On the other hand, cryoballoon ablation of left atrial (LA) roof has been performed using a conventional cryoballoon system (Arctic Front Advance Pro [AFA-Pro]) in addition to PVI. However, cryoballoon ablation of LA roof with POLARx has not been investigated yet.

Methods

We performed cryoballoon ablation of LA roof with POLARx in 22 patients after we achieved PVI. After the cryoballoon ablation, complete conduction block at LA roof and isolation of all PVs were confirmed by creating an activation map during high right atrium pacing. If they could not be obtained with solely a cryoballoon, touch up ablation with radiofrequency ablation was permitted. The procedural data during ablation with POLARx was compared with those during ablation with AFA-Pro we had performed in a historical cohort of patients (n=46).

Results

Complete conduction block at LA roof without touch up ablation could be obtained in all the patients in POLARx group and 44 (95.7%) patients in AFA-Pro group. Total procedure time was almost similar in both groups (164.2±35.4 min for POLARx vs 180.3±35.4 min for AFA-Pro, p=0.10). During LA roof line ablation, nadir balloon temperature was significantly lower in POLARx group (right side: −53.6±4.4°C for POLARx vs −45.6±4.6°C for AFA-Pro, p<0.01, central part: −56.4±4.3°C for POLARx vs −46.0±3.7°C for AFA-Pro, p<0.01, left side: −55.1±3.5°C for POLARx vs −45.7±5.3°C for AFA-Pro, p<0.01), and balloon temperature reached −40°C earlier in POLARx (right side: 30.7±8.9 sec for POLARx vs 78.0±39.8 sec for AFA-Pro, p<0.01, central part: 30.6±9.3 sec for POLARx vs 65.9±33.3 sec for AFA-Pro, p<0.01, left side: 30.4±4.2 sec for POLARx vs 78.8±49.6 sec for AFA-Pro, p<0.01). Total freezing time required for LA roof line ablation was significantly shorter in POLARx group (589.3±163.6 sec for POLARx vs 877.5±191.7 sec for AFA-Pro, p<0.01).The scar area created after LA roof line ablation was similar in both groups (9.3±4.1 cm2 for POLARx vs 11.0±4.8 cm2 for AFA-Pro, p=0.23).

Conclusion

Complete conduction block at LA roof could be obtained after cryoballoon ablation with POLARx, in the same way as AFA-Pro. Lower nadir balloon temperature could be expected in shorter freezing time during LA roof line ablation in using POLARx compared with AFA-Pro.

Funding Acknowledgement

Type of funding sources: None.

How to perform effective cryoballooon ablation of left atrial roof: considerations after experiences of more than 1000 cases

Introduction

Although pulmonary vein isolation is the cornerstone of atrial fibrillation (AF) ablation, concomitant cryoballoon ablation of left atrial (LA) roof has been expected to improve clinical outcomes after ablation. We demonstrate characteristics and efficacy of cryoballoon ablation of LA roof through our experiences from a large volume of procedures.

Methods

We had performed cryoballoon ablation of LA roof in 1036 procedures including 202 redo procedures in AF patients since June 2016. Among these procedures, we analyzed 834 patients (309 paroxysmal AF) who had undergone de novo ablation for AF. We confirmed whether the complete conduction block of LA roof line was obtained after the ablation.

Results

LA roof line block was obtained in 767 patients (92.0%) without touch up ablation with a radiofrequency catheter (Group A). LA diameter (LAD) was significantly smaller (43.6±6.6mm vs 47.4±7.5mm, p<0.01) and body mass index (BMI) was significantly lower (24.9±4.0kg/m2 vs 26.3±4.6kg/m2, p=0.01) in those in Group A compared with those without LA roof line block after cryoballoon ablation (Group B). Compared with those in Group B, cryoballoon application number of LA roof (4.1±1.2 vs 4.5±1.6, p<0.01) and mean nadir of cryoballoon temperature during cryoballoon ablation of LA roof (−44.5±5.6°C vs −40.5±7.5°C, p<0.01) were significantly lower in those in Group A. Regarding cryoballoon application number, the number of the cryoballoon application in which a cryoballoon was applied to LA roof with the guiding catheter located in a left superior pulmonary vein (LSPV) was significantly lower in patients in Group A (1.3±0.8 vs 1.6±1.0, p=0.02), and when the number was less than 2, mean nadir of cryoballoon temperature was significantly lower compared with when it was 2 or more than 2 (−44.8±5.8°C vs −42.8±5.6°C, p<0.01). Among those refer to first ablation procedures, one-year Kaplan-Meier atrial arrhythmias free rate estimates, 80.6% for those in Group A and 59.0% for those in Group B (p<0.01). Multivariate analysis identified LA roof line block without touch up ablation as one of the predictors of atrial arrhythmias recurrences. Atrial tachycardia depending on LA roof occurred after cryoballoon ablation of LA roof in 8 patients, although LA roof line block without touch up ablation could be obtained in the index ablation procedure in 6 patients among them.

Conclusion

LA roof line block could be obtained by solely cryoballoon with a reasonable success rate, especially in those with smaller LAD and lower BMI. To obtaine LA roof line block, cryoballoon ablation with the guiding catheter located in LSPV is preferable. LA roof line block without touch up ablation brings better clinical outcomes in those who underwent cryoballoon ablation of LA roof.

Funding Acknowledgement

Type of funding sources: None.

Prognostic implications of fractional flow reserve and coronary flow reserve after newer-generation drug-eluting stent implantation

Background

FFR after percutaneous coronary intervention (PCI) has been reported to provide prognostic information. However, limited data are available regarding the prognostication by CFR in patients treated with elective PCI using newer generation DES.

Purpose

This study aimed to assess the prognostic value of post-procedural fractional flow reserve (FFR) and coronary flow reserve (CFR) after newer-generation drug-eluting stent implantation (DES).

Methods

A total of 466 stenoses in 466 patients underwent FFR-guided PCI. FFR and CFR measurements before and after PCI by a pressure-temperature sensor-tipped wire were performed. Follow-up data were studied to determine the predictors of target vessel failure (TVF), defined as death, target vessel-related nonfatal myocardial infarction, and unplanned clinically driven target vessel late revascularization. Prognostic value of post-PCI CFR was compared with that of FFR or FFR/CFR combination.

Results

After PCI completion, 13.7% showed post-PCI FFR ≤0.80 and 44.2% exhibited post-PCI CFR <2.5. Discordant results were observed in 42.5% (198/466). During 2.7 (1.8–3.3) years follow-up, 57 (12.2%) TVF were documented. The multivariable Cox proportional hazard regression analysis revealed that post-PCI FFR and post-PCI CFR were independent prognostic factors. ROC analysis revealed that the optimal cut-off values of post-PCI FFR and CFR values were 0.85 and 2.26, respectively. Significant differences in TVF were detected according to post-PCI FFR (≤0.85 vs >0.85: 17.8% vs 8.9%, P<0.05) and post-PCI CFR (≤2.26 vs >2.26: 20.5% vs 7.2%, P<0.01), although the reclassification ability for TVF was improved only with post-PCI CFR (net reclassification index 0.598; P<0.01; integrated discrimination index 0.038; P<0.01), but not with post-PCI FFR, in comparison with the clinical model. Compared with patients with FFR >0.85, those with post-PCI FFR ≤0.85 and CFR ≤2.26 showed significantly higher risk of TVF (8.9% vs 28.9%, P<0.01, HR 4.24, 95% CI 2.40–7.50, P<0.01), whereas those with post-PCI FFR <0.85 and CFR >2.26 had similar TVF risk (8.9% vs 9.2%, P=1.00, HR 1.01, 95% CI 0.47–2.16, P=0.97).

Conclusions

After PCI completion with newer-generation DES, discordant results between FFR and CFR were observed in 42.5%. Compared with post-PCI CFR, post-PCI FFR provided limited reclassification ability for TVF. Among patients with lower post-PCI FFR, only patients with lower post-PCI CFR showed significantly higher risk of TVF than those with higher post-PCI FFR.

Funding Acknowledgement

Type of funding sources: None.

Robust association between changes in coronary flow capacity following PCI and vessel-oriented outcomes

Backgrounds

While trials show a comparative effectiveness of percutaneous coronary intervention (PCI) against medical therapy with respect to patient outcomes, deferring all elective PCI might be too simplistic, given the prognostic benefit differential according to several factors. Coronary flow capacity (CFC) is a potentially useful coronary flow (CF)-related physiologic marker of ischemia for guiding PCI indication [1,2]. However, the physiological/prognostic mechanics of the CFC guidance, which could be assessed by CFC changes following PCI, have not been investigated.

Objectives

To assess the determinants and prognostic implication of the change in the CFC status following PCI.

Methods

From a single center registry, 450 patients with chronic coronary syndrome (CCS) who underwent fractional flow reserve (FFR)-guided PCI with pre-/post-PCI coronary physiological assessments by thermodilution-method were included. CFC status was defined as follows [1]; normal CFC as CFR ≥2.80 with hyperemic CF (hCF) ≥3.70; mildly reduced CFC as CFR <2.80 and ≥2.10, combined with hCF <3.70 and ≥2.56; moderately reduced CFC as CFR <2.10 and ≥1.70, and 1/Tmn <2.56 and ≤2.00; and severely reduced CFC otherwise (CFR <1.70 and hCF <2.00). Associations between PCI-related changes in thermodilution method-derived CFC categories and incident target vessel failure (TVF) during a median follow-up of 4.3 (IQR: 2.5, 6.9) years were assessed by multivariate COX proportional hazard models.

Results

The mean (SD) age was 67.1 (10.0) years and there were 75 (16.7%) women. There were no differences in survival according to pre-PCI CFC status (P for linear trends = 0.22). Compared with patients showing no change in CFC categories after PCI, patients with category worsened, +1, +2, and +3 category improved had the hazard ratio (95% CI) for incident TVF of 2.27 (0.95, 5.43), 0.85 (0.33, 2.22), 0.45 (0.12, 1.63), and 0.14 (0.016, 1.30), respectively (P for linear trends = 0.0017). The relevant Kaplan-Meier curves were illustrated in the Figure, which highlights a best survival in those with +3 categories improvement (severely reduced to normal CFC) and worst in worsened CFC. After adjustment for confounders, one additional improvement in CFC status was associated with 0.61 (0.45, 0.83) times the hazard of TVF. CFC changes ≥3 categories were largely predicted by pre-PCI CFC with area under the curve of 0.94 (95% CI: 0.93, 0.96), and 48.6% of the variability of continuous CFC changes in ranks was explained solely by pre-PCI CFC, while only 12.4% by FFR.

Conclusion

CFC improvement following PCI, which was largely determined by the pre-PCI CFC status, was associated with lower risk of incident TVF in patients with CCS who underwent PCI. Therefore, CFC changes provide a mechanistic explanation on a potential favorable effect of PCI on reducing vessel-oriented outcome in lesions with reduced CFC and low FFR.

Funding Acknowledgement

Type of funding sources: None.

Prevalence and culprit lesion plaque characteristics on optical coherence tomography in patients with non-st-segment elevation acute coronary syndrome with zero coronary calcification on coronary CTA

Background

CAC evaluated by non-contrast computed tomography is a marker of atherosclerosis. However, the characteristic features of CCTA and optical coherence tomography (OCT) of culprit lesions in patients with NSTE-ACS showing zero CAC remain unknown.

Objectives

This study aimed to assess the prevalence and characteristic features of culprit lesions on coronary CT angiography (CCTA) and optical coherence tomography (OCT) in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) showing zero coronary artery calcium (CAC).

Methods

A total of 176 consecutive patients with NSTE-ACS who underwent preprocedural CCTA and OCT were studied. Patients were divided into two groups according to their CAC (zero-CAC and non-zero-CAC groups). Baseline characteristics, CCTA and OCT findings were compared between these two groups.

Results

The prevalence of patients with zero-CACS was 15.9% (28/176). Patients in zero CAC group were younger (mean age, 55 vs. 65 years, P<0.001) and had a lower prevalence of diabetes (10.7 vs 37.2%, P=0.012) than non-zero CAC group. In zero CAC group, the lower prevalence of napkin ring sign (3.5% vs. 28.4%, P=0.028), smaller LV mass index (77.7 vs. 83.9, P=0.04), lower prevalence on spotty calcification (0 vs. 83.8%, P<0.001), lower epicardial fat volume (111.3 vs. 142.6 cm3, P=0.025), and lower pericoronary adipose tissue attenuation (−71.5 vs. −70.2 HU, P=0.07) on CCTA were observed. On OCT, the frequency of plaque erosion (82.1 vs. 44.6%, P<0.001) was significantly higher in zero-CACS group. The prevalence of lipid-rich plaque (46.4 vs. 86.5%, P<0.001), thin-cap fibroatheroma (17.9 vs. 46%, P=0.006), macrophage accumulation (46.4 vs. 81.8%, P<0.001) and cholesterol crystal (7 vs. 41.9%, P<0.001) were all significantly lower in zero-CAC group.

Conclusions

Zero CAC NSTE-ACS was not rare. Zero-CAC NSTE-ACS was characterized by specific phenotypes defined by the combined assessment of CCTA and OCT. Further studies are warranted if these characteristics of NSTE-ACS on preprocedural imaging studies provide prognostic information or guidance of a specific therapeutic approach.

Funding Acknowledgement

Type of funding sources: None.

Relationship between OCT-derived plaque characteristics, CTA-derived coronary inflammation, and CMR-derived global coronary flow reserve in patients with acute coronary syndrome

Background

The presence of layered plaque is suggestive of recurrent thrombotic events. However, the impact of layered plaque detected by optical coherence tomography (OCT) on coronary inflammation and coronary flow reserve remains unclear.

Purpose

We aimed to investigate the association of OCT-derived layered plaque with pericoronary adipose tissue inflammation assessed by coronary computed tomography angiography (cCTA) and global coronary flow reserve (G-CFR) assessed by cardiac magnetic resonance imaging (CMR) in patients with acute coronary syndrome (ACS).

Methods

We investigated 88 patients with first ACS who underwent preprocedural cCTA and OCT imaging of the culprit lesion, and CMR after percutaneous coronary intervention (PCI). All patients were divided into four groups according to the OCT-derived culprit plaque characteristics: layered vs. non-layered plaque; and plaque rupture vs. plaque erosion. Coronary inflammation was assessed by the mean value of pericoronary adipose tissue (PCAT) attenuation (−190 to −30 HU) of the three major coronary vessels. G-CFR was obtained by quantifying absolute coronary sinus flow at rest and during maximum hyperemia. CCTA and CMR findings were compared between the groups.

Results

In a total of 88 patients, layered plaque [L] with plaque rupture [PR] was observed in 25 patients, layered plaque with plaque erosion [PE] was observed in 26 patients, non-layered plaque [NL] with PR was observed in 23 patients, and non-layered plaque with PE was observed in 14 patients, respectively. Three-vessel-PCAT attenuation value (L-PR vs. L-PE vs. NL-PR vs. NL-PE; −68.13±6.18 vs. −69.01±6.72 vs. −69.76±4.04 vs. −74.61±5.63 HU, P=0.009) and culprit vessel PCAT attenuation value (L-PR vs. L-PE vs. NL-PR vs. NL-PE; −66.39±7.38 vs. −68.94±8.06 vs. −70.01±5.76 vs. −75.45±6.60 HU, P=0.003) showed the graded difference between the four groups. G-CFR value also showed the graded difference between the four groups (L-PR vs. L-PE vs. NL-PR vs. NL-PE; 2.26 [1.80–2.87] vs. 2.24 [1.72–3.13] vs. 2.97 [2.24–3.83] vs. 3.18 [2.67–4.08], P=0.022).

Conclusions

The presence of layered plaque at the culprit lesion was associated with high PCATA and low G-CFR in patients with ACS. Detection of layered plaque may indicate increased pericoronary inflammation and impaired coronary flow reserve, potentially providing the risk stratification in patients with ACS.

Funding Acknowledgement

Type of funding sources: None.

Prognostic value of machine learning for acute heart failure

Funding Acknowledgements

Type of funding sources: None.

Background

At onset of acute heart failure (AHF), various clinical fundamental parameters including vital sign, laboratory data, or initial treatment were investigated, and we can roughly estimate the prognosis. However, machine learning method for prediction of the prognosis was not studied.

Purpose

To elucidate prognostic value of machine learning for AHF comparing conventional statistical model.

Methods

We enrolled consecutive 300 patients with AHF (79.5 ± 12.1 years, 158 Males). Patients with acute coronary syndrome, mechanical circulatory support cases, and cardio-pulmonary arrest cases were excluded. The patients were randomly divided into 80% (240 cases) and 20% (60 cases), and the former was used as train data, and the latter as validation data. Objective variable was set as cardiac death in one year. First, logistic regression analysis with Akaike’s information criterion (AIC) was performed, and extracted predictive parameters. The predictive model for the cardiac prognosis was constructed by cut-off value of ROC curve analysis of propensity score was calculated. Next, machine learning (random forest method and deep learning) to build predictive model was performed with the predictors. Finally, accuracy of each predictive model was compared.

Results

Thirty cases showed cardiac death in one year. Logistic regression with AIC extracted 8  predictors, and the cut off-value of propensity score with the 6 parameters was 0.110. The accuracy was 0.714 and area under ROC (AUROC) was 0.836. Conversely, random forest method demonstrated the accuracy as 0.927, AUROC 0.860. On deep learning, the accuracy was 0.937 and AUROC 0.901. 

The top 4 high feature importance of random forest were Cl/red blood cell count/pH/Anion Gap. However, accuracy of those predictors was lower than that of machine learning.

Conclusion

Machine learning was a powerful tool to predict cardiac prognosis of AHF, comparing with conventional statistical model. Abstract Figure. Statistical model

Diagnostic performance of deep learning on 12-leads electrocardiography for recurrence after pulmonary vein isolation in patients with persistent atrial fibrillation

Background

Several patients with persistent atrial fibrillation (per-AF) suffer from recurrence after pulmonary vein isolation (PVI). Various methods to predict the recurrence were tried, but deep learning on 12-leads electrocardiography (ECG) after PVI was not studied.

Purpose

To elucidate diagnostic performance of deep learning on 12-leads ECG after PVI in patients with per-AF

Methods

We enrolled consecutive 109 patients with per-AF who underwent PVI (68.8±10.0 years, 83 males) excluding failure cases. We defined recurrence in 3–12 months after PVI. From the ECG just after PVI, five beats of each lead were sampled separately. Deep learning (convolutional neural network on bitmap ECG image) was performed by transfer learning of Inception-Resnet-V2 model. Gradient weighted class activation color mapping (GradCam) was performed to detect convolutional importance in the lead.

Results

Thirty-six patients showed recurrence in the period. Lead II (accuracy 0.701), aVR (0.690) were the top 2 leads of prediction, which showed larger accuracy than statistical accuracies of Non PV foci = SVC (accuracy = 0.541) and left atrial diameter >50mm (0.596). In lead II, GradCam spotlighted strong convolution of latter half of P wave in recurrent case, and former half of P wave and T wave in no-recurrent case.

Conclusions

Deep learning on ECG was a powerful tool to predict recurrence of per-AF after PVI.

Funding Acknowledgement

Type of funding sources: None. Results of deep learningResults of GradCam

Long-term prognostic factors of coronary artery disease patients after out-of-hospital cardiac arrest

Background

The long-term prognosis of survival in patients with out-of-hospital cardiac arrest (OHCA) with coronary artery disease (CAD) remains poor.

Methods

There were 2391 out-of-hospital cardiac arrest (OHCA) patients transferred to 2 hospitals. We included 405 cardiovascular arrest patients, who got return of spontaneous circulation (ROSC) from January 2015 to December 2018. Among them, 204 patients had CAD that caused OHCA (39%: multi-vessel disease, 19%: chronic total occlusion (CTO), 13%: vasospastic angina (VSA)). To predict mortality, we investigated patients' characteristics, pre-hospital information and findings of CAG.

Results

At 1-year later, 104 patients (51%) survived. Younger age (P<0.001), VF survivor (P<0.001), pre-hospital ROSC (P<0.001), bystander CPR (P=0.013), without ECMO (P<0.001), lower lactate level on admission (P<0.001), and higher geriatric nutritional risk index score (P<0.001) were associated with low 1-year mortality, while with ST-segment elevation (P=0.778), BMI level (P=0.344), and sex (0.401) were not. And in the findings of CAG, the past history of CAD (P=0.049), the higher number of coronary vessel disease (P=0.003) such as multi-vessel disease (P=0.022), higher SYNAX score (P=0.016), and larger infarct size (max CK level; P=0.013, max CK-MB level; P<0.001) were associated with high 1-year mortality. On the other hand, acute coronary syndrome (P=0.300), any coronary lesion (RCA (P=0.447), LAD (P=0.089), LCX (P=0.096), or LMT (P=0.842)), and with CTO lesion (P=0.140) were not associated. Zero-vessel disease (VSA, P=0.001) had lower mortality among the CAD patients. In the multivariate Cox proportional hazards model, age (hazards ratio; HR: 1.03, 95%confidence interval (CI) 1.00–1.06, P<0.001) and bystander CPR (HR: 0.36, 95% CI 0.20–0.65, P<0.001) were the independent predictors of mortality.

Conclusions

Younger age and pre-hospital support after OHCA with CAD were the predictors of low mortality. Pre-hospital information, systemic condition on arrival, or anatomical coronary complexity were important to predict low mortality.

Funding Acknowledgement

Type of funding sources: None.

Neurological outcome at 30-day as an estimator of 1-year functional status after out-of-hospital cardiac arrest with post-encephalopathy

Background

Implantation of implantable cardioverter-defibrillators (ICD) for secondary prevention is fully recommended for those with an estimated survival over 1-year with a good functional status. However, we often face the difficulty to estimate the functional status and hesitate to implant ICD for patients with post-resuscitation encephalopathy.

Methods

There were 2391 out-of-hospital cardiac arrest (OHCA) patients transferred to 2 hospitals. We included 405 cardiovascular arrest patients, who got return of spontaneous circulation (ROSC) from January 2015 to December 2018. Among the patients, 343 patients could be considered to be implanted ICD for secondary prevention according to the initial waveform or the causes of OHCA. At 1-month later, 184 patients (54%) survived. To assess the association of functional status at 30-day and 1-year, we investigated patients' characteristics, pre-hospital information and clinical findings, and evaluated the neurological outcome according to the cerebral performance category (CPC) scale.

Results

At 1-month later, 145 patients (79%) survived with CPC≤2, and 39 patients (21%) survived with CPC>2. Bystander CPR (P=0.009), pre-hospital ROSC (P<0.001), low lactate level on admission (P=0.001), high geriatric nutritional risk index score (P<0.001) and without ECMO (P=0.002) were significantly associated with good neurological outcome at 30-day. The 1-year Kaplan-Meier event rate revealed significantly different survival rate (CPC>2 at 30-day:38.5%, vs CPC≤2 at 30-day:97.2%; P<0.001). In multivariate analysis, CPC scale at 30-day (OR 0.022; 95% CI 0.003–0.140; p<0.001) was the independent predictor of favorable neurological outcome at 1-year. Among the patients with CPC>2 at 30-day, only 3 patients (7.7%) of CPC=3 achieved the improvement of neurological outcome at 1-year (CPC≤2), while no patient of CPC=4 did. And one patient (2.5%) with CPC=3 was implanted ICD during the follow-up period. Twenty-five patients (64%) died of non-cardiovascular death with frailty of post-resuscitation encephalopathy after they were transferred to other hospital with the acceptation and intention of the do-not-attempt-resuscitation.

Conclusions

Neurological prognosis at 30-day after OHCA might be an estimator of 1-year functional status to guide us to implant ICD for secondary prevention.

Funding Acknowledgement

Type of funding sources: None.

Prediction for cardiac prognosis in patients with congestive heart failure by machine learning on dual-isotope myocardial semiconductor SPECT

Background

Dual-isotope (low doze 201TlCl and 123I-β-methyl-P-iodophenyl-pentadecanoic acid (BMIPP)) single photon emission computed tomography (SPECT) is utilized to estimate myocardial damage in patients with congestive heart failure (CHF). However, predictive model construction on the SPECT for cardiac death by machine learning was not studied.

Purpose

To elucidate predictive value of machine learning model on dual-isotope SPECT for CHF.

Methods

We enrolled consecutive 310 patients who admitted with CHF (77.1±3.1 years, 164 males). After initial treatment, they underwent electrocardiography gated SPECT and observed in median 507 days [IQR: 165, 1032]. Multivariate Cox regression analysis for cardiac death was performed, and predictive model was constructed by ROC curve analysis and machine learning (Random Forest and Deep Learning). The accuracies (= [True positive + True negative] / Total) of the prediction models were compared with ROC curve model.

Results

Thirty-six patients fell into cardiac death. Cox analysis showed Age, left ventricular ejection fraction (LVEF), summed rest score (SRS) of BMIPP, and mismatch score were significant predictors (Hazard ratio: 1.068, 0.970, 1.032, 1.092, P value: <0.001, 0.014, 0.002, <0.001, respectively). ROC curve analysis of them revealed the accuracy of the cut-off value was 0.479–0.773. Conversely, machine learning model demonstrated higher accuracy for cardiac death (Random Forest: 0.895, Deep Learning: 0.935). The top 4 feature importance of the random forest were LVEF (0.299), SRS BMIPP (0.263), Age (0.262), and mismatch score (0.160).

Conclusion

Machine learning model on SPECT was superior to conventional statistic model for predicting cardiac death in patients with CHF.

Funding Acknowledgement

Type of funding source: None

Comparison of neointimal coverage between biodegradable-polymer everolimus-eluting stent and durable-polymer everolimus-eluting stent using angioscopy for the patients with acute coronary syndrome

Background

New-generation biodegradable-polymer platinum chromium everolimus-eluting stent (BP-PtCr-EES) is available, which has different polymer and alloy compare to more established stent design, a durable-polymer cobalt-chromium everolimus-eluting stent (DP-CoCr-EES).

Purpose

To compare neointimal coverage (NIC) between BP-PtCr-EES and DP-CoCr-EES by using coronary angioscopy (CAS).

Methods

A total of 36 patients (44 stents) with BP-PtCr-EES or DP-CoCr-EES who underwent CAS at 1 year after stenting were investigated. We compared angioscopic findings assessed by angioscopy between BP-PtCr-EES (n=18) and DP-CoCr-EES (n=26). NIC grade and yellow plaque grade (YPG) was adopted from earlier reports from grade 0 to 3. We determined maximum (max-) and minimum (min-) NIC grade and heterogeneity score (HGS = max NIC grade minus min NIC grade). We also assessed YPG and the presence of thrombus (TH).

Results

Six lesions (33.3%) in BP-PtCr-EES group and 7 (26.9%) lesions in DP-CoCr-EES group were culprit lesions of acute coronary syndrome, which did not statistically differ between the two groups (p=0.74). And there were no significant differences in stent diameter (BP-PtCr-EES: 2.97±0.39 mm vs DP-CoCr-EES: 3.14±0.45 mm, p=0.22) and length (BP-PtCr-EES: 26.9±7.9 mm vs DP-CoCr-EES: 28.4±8.0 mm, p=0.54). In terms of CAS findings, BP-PtCr-EES group has better neointimal coverage than DP-CoCr-EES group (max NIC grade: 2.6±0.7 vs 2.0±0.9, p=0.01. min NIC grade: 1.1±0.8 vs 0.5±0.5, p<0.01), but HGS was almost same (1.6±0.7 vs 1.5±0.9, p=0.70). YPG of BP-PtCr-EES group showed significantly lower than DP-CoCr-EES group (1.0±1.0 vs 1.7±1.0, p=0.02). The rate of TH was significantly lower in BP-PtCr-EES group than DP-CoCr-EES group (25%, n=6, vs 75%, n=18, p=0.03). There were no clinical events such as stent thrombosis or restenosis during the observation period in both stent groups.

Conclusion

Superior neointimal coverage and less YPG or TH were observed by CAS in the BP-PtCr-EES group at 1 year after stenting. Clinical significance was still unknown because of no clinical events in both groups. Prospective and large populations studies may be required.

Funding Acknowledgement

Type of funding source: None

The comparison of the chronic-phase vascular healing between bioabsorbable and durable polymer drug eluting stent by using optical coherence tomography

Background

Bioabsorbable polymer drug eluting stents (BP-DESs) were designed to reduce a vascular inflammatory reaction compared to durable polymer drug eluting stents (DP-DESs). However, few studies have compared vascular responses to BP-DESs and DP-DESs.

Methods

We enrolled 88 consecutive patients with single culprit coronary artery lesions (31 lesions with acute coronary syndrome) undergoing a single stent-implantation. BP-DESs and DP-DESs were implanted in 50 (57%) and 38 patients (43%), respectively. All lesions underwent optical coherence tomography examination at chronic phase and intrastent OCT findings at the follow-up were evaluated in every 1-mm cross-sections (CSs).

Results

A total of 1887 CSs (BP-DES: 1096, DP-DES: 791) were analyzed. The median period of follow-up OCT was 293 (250–374) days. There were no differences in the patient, lesion, and initial clinical presentation of acute coronary syndrome (ACS). BP-DESs had significantly higher percent neointimal hyperplasia area, defined as neointimal hyperplasia area divided by stent area x 100 (18.4±9.0% vs. 16.1±9.9%, p<0.001), fewer malapposed struts (1.7% vs. 3.9%, p=0.005), fewer uncovered struts (3.6% vs. 5.8%, p=0.02) but higher frequency of superficial low intensity neointima (LIN) (7.7% vs. 3.4%, p<0.001). Multivariate logistic analysis showed that BP-DES (OR: 2.5, 95% CI: 1.49–4.08, p<0.001) and the initial clinical presentation of ACS (OR: 2.31, 95% CI: 1.47–3.62, p<0.001) are independent predictive factors for LIN.

Conclusion

BP-DESs showed homogenous neointimal growth and complete stent coverage quantitatively. Meanwhile, the significant relationships of BP-DES with LIN may suggest that the neointimal quality remains immature in BP-DESs in this period.

Funding Acknowledgement

Type of funding source: None

Optical coherence tomography findings in healed vulnerable plaques in patients with coronary artery disease

Background

Histopathological analysis or intracoronary image assessment of healed plaques (HPs) has been reported both in acute coronary syndrome (ACS) and stable angina pectoris (SAP) patients. However, background characteristics or lesion morphologies of HPs could not be fully clarified and their differences according to the clinical status remain undetermined.

Purpose

We sought to investigate the clinical and morphological characteristics and compare their differences among ACS and SAP patients in order to clarify the clinical significance in HPs lesions.

Methods

We enrolled consecutive 201 patients with 213 native coronary artery lesions (139 lesions with SAP, 42 ST elevation-ACS (STE-ACS) and 32 non-ST elevation ACS (NSTE-ACS) undergoing pre-intervention optical coherence tomography (OCT). HPs was defined as layered phenotype on OCT. Clinical and angiography characteristics and lesion morphologies on OCT were assessed.

Results

HPs were observed in 110 lesions (51.6%) and their prevalence were not different according to the clinical status (SAP:55.1%, STE-ACS:38.1%, NSTE-ACS:56.3%, p=0.14). Lesions with HPs had higher frequencies of angiography-eccentric lesions (62.7% vs. 35.9%, p<0.001) and OCT-macrophages (65.5% vs. 43.1%, p<0.001), and greater OCT-lumen area stenosis (%-AS) (77.1±10.2% vs. 73.6±10.6%, p=0.01) than those without HPs. Of lesions with HPs, OCT-thin-cap fibroatheroma (SAP 14.4%, STE-AC43.8%, NSTE-ACS 16.7%, p=0.03), plaque rupture (5.3%; 37.5%; 11.1%, p<0.001) and thrombus (6.6%, 75.0%, 22.2%, p=0.007) were more frequently observed in STE-ACS than in SAP patients, whereas OCT-microvessels were more frequent in SAP than in ACS patients (19.7%, 0.0%, 0.0%, p=0.02). Other OCT findings such as macrophages, cholesterol crystal, multiple layered phenotype, and %-AS were not significantly different according to the clinical status. Multivariate logistic regression analysis identified the angiography-eccentric lesions (odds ratio (OR): 2.97, 95% confidence intervals (CI): 1.68–5.25, p<0.001) and OCT macrophages (OR 2.41, 95% CI 1.36–4.27, p=0.003) as independent related factors for the existence of HPs.

Conclusions

The present study showed that HPs lesions had eccentric and large plaque burden, and persistent plaque inflammations regardless of clinical status, which might lead to future coronary events.

Funding Acknowledgement

Type of funding source: None

Optical coherence tomography and coronary angioscopy assessment of healed vulnerable plaque components in patients with coronary artery lesions undergoing elective percutaneous coronary intervention

Background

Many vulnerable plaques would progress without clinical events and might result in healed plaques (HPs). Histopathological or intracoronary image assessment of HPs has been reported. However, the morphological characteristics of HPs remain unclear yet.

Purpose

We sought to assess the healed vulnerable plaque components in patients with coronary artery lesions using optical coherence tomography (OCT) and coronary angioscopy (CAS).

Methods

We enrolled 47 patients with 50 native coronary artery lesions with angiographical severe stenosis (>90% diameter-stenosis) and without severe calcification (36 lesions with stable angina pectoris (SAP) and 14 acute coronary syndrome (ACS)) undergoing pre-intervention OCT and CAS. HPs was defined as layered phenotype on OCT. Lesion morphologies and plaque characteristics in lesions with HPs were assessed using OCT and CAS images.

Results

HPs were observed in 27 lesions (54.0%) and their prevalence were similar among each clinical status (SAP 52.8%, ACS 57.1%, p=1.00). Lesions with HPs had higher prevalence of OCT-macrophage (88.0% vs. 52.0%, p=0.01), CAS-red thrombus (88.8% vs. 52.2%, p=0.004) and CAS-low grade-yellow plaque (grade 1) (55.6% vs. 21.7%, p=0.02) than those without. SAP lesions with HPs had higher prevalence of CAS-yellow plaque (35.3% vs. 5.9%, p=0.09) and OCT-thin-cap fibroatheroma (42.1% vs. 5.9%, p=0.04) than SAP without HPs. ACS lesions with HPs had less CAS-red thrombus (0.0% vs. 50.0%, p=0.03) and OCT-plaque rupture (12.5% vs. 66.7%, p=0.04) than ACS without HPs. Multivariate logistic regression analysis revealed that OCT-macrophages (odds ratio (OR): 6.65, 95%-confidence intervals: 1.07–41.5, p=0.043), CAS-red thrombus (OR 8.77, 95% CI 1.33–57.8, p=0.02), and low grade-yellow plaque (OR 13.05, 95% CI 1.97–86.5, p=0.008) were independently related with the existence of HPs lesions. Combination of these 3 factors showed a high predictive value of OCT-HPs lesions (90.9%).

Conclusions

HPs lesions showed the lower lesion vulnerability than common ACS lesions but had more intraplaque inflammatory condition compared with common SAP lesions. Combined CAS and OCT examination might be useful to clarify the plaque components of HPs lesions in vivo, leading to help us understand the clinical significance of HPs.

Funding Acknowledgement

Type of funding source: None

Differences of ST level at J-point on 12-lead electrocardiography can distinguish takotsubo syndrome and acute anterior myocardial infarction

Background

Qualitative difference of ST elevation/depression on 12-leads electrocardiography (ECG) at onset was reported in patients with Takotsubo syndrome (TTS) and acute anterior myocardial infarction (ant AMI). However, quantitative difference of those was not elucidated.

Purpose

To investigate differences of ST level at J point on ECG between TTS and ant AMI by automated calculating system.

Methods

We firstly enrolled consecutive 40 patients of TTS, and among 500 ant AMI patients, one to two random matching was done by their age and gender. Finally, 40+80 patients (74.5±11.2 years, 87 females) were enrolled. ECG at onset of both group was measured by automated system (ECAPs12c: Nihon-Koden).

Results

ST level of TTS at J-point in I/II/V4–6 lead was significantly elevated comparing to that of ant AMI. Conversely, Conversely, significant ST depression in aVR and no ST elevation in V1 of TTS was observed in TTS. Logistic regression analysis revealed that ST elevation in I lead and no ST elevation in V1 lead showed high odds ratio and low P value.

Conclusion

Automated measured ST level at J-point was a powerful tool to distinguish TTS and ant AMI at onset.

Funding Acknowledgement

Type of funding source: None

Pulmonary vein isolation for atrial fibrillation patients with reduced left ventricular ejection fraction

 

Background/Introduction Pulmonary vein isolation (PVI) is a cornerstone of curable treatment for atrial fibrillation (AF). Left ventricular (LV) ejection fraction (EF) occasionally improves after PVI in AF patients with reduced LVEF (rEF), the mechanism of which is not fully understood. CASTLE-AF trial have demonstrated that PVI with radiofrequency (RF) catheter for AF patients with rEF can reduce their mortality and heart failure. Nevertheless there are limited data about the clinical outcome of the PVI for patients with impaired LV function.

Purpose

This study was to evaluate the efficacy of PVI and improvement of LVEF after the procedure in AF patients with rEF.

Methods

A total of 2709 consecutive AF patients (age 65±39 y/o, male 67%) underwent their first PVI with cryoballoon or RF catheter in our facility from April 2014 to March 2019, and retrospectively analyzed. All the patients underwent echocardiogram before and half to one year after the procedure. Patients with LVEF under 40% before the PVI were selected (n=111) and divided into two groups based on whether there were specific etiologies of LV function impairment (group A) or not (group B).

Results

There were no significant difference in mean LVEF between group A (n=40) and group B (n=71) (32±6% vs 33±6%, p=0.12). The major etiology of rEF in group A were old myocardial infarction (n=20, 18%), hypertensive heart disease (n=6, 5.4%), and dilated cardiomyopathy (n=5, 4.5%). After mean follow-up of 2.7 years, there were no significant difference in clinical outcome after the procedure between two groups (1-year Kaplan–Meier event rate estimates; 72.2% vs 72.9%; p=0.85). The change amounts of LVEF after the PVI were significantly higher in group B (20±14%) compared to group A (2±10%) (p<0.001). Multivariable Cox regression analysis revealed that age was the independent significant predictors of EF improvement over 10% in group B (p=0.048).

Conclusions

In AF patients with reduced LVEF, there were no significant difference in efficacy of PVI between those who have specific etiologies of LV function impairment other than AF and who have not. The improvement of LVEF after PVI was significantly larger in patients without specific etiologies compared to those with.

Funding Acknowledgement

Type of funding source: None

Diagnostic performance of 18-leads electrocardiography to distinguish takotsubo syndrome and acute anterior myocardial infarction

Background

Electrocardiographic (ECG) features on acute phase of Takotsubo syndrome (TTS) is recognized to mimic that of acute anterior myocardial infarction (ant AMI). However, the difference of synthesized 18-leads ECG of both diseases was not elucidated.

Purpose

To elucidate diagnostic performance of 18-leads ECG to distinguish TTS and acute anterior AMI.

Methods

We firstly enrolled consecutive 40 patients of TTS, and among 500 ant AMI patients, one to two matching was done by their age and gender. Finally, 40+80 patients (74.5±11.2 years, 87 females) were enrolled, and ECG at onset of both group was estimated. Because of multicollinearity, all significant differences were compared by machine learning (Random Forest method).

Results

Prevalence of Q wave had no difference. Conversely, ST depression in TTS and ST elevation in ant AMI were significant differences in V7–9 leads. T-wave polarity of V3R-V9 leads were significantly different (flat T-wave in TTS and positive in ant AMI). Machine learning revealed T wave polarity in V7 lead had the highest feature importance.

Conclusion

18-leads ECG at onset had powerful diagnostic performance to distinguish the two diseases.

Funding Acknowledgement

Type of funding source: None

Toll-like Receptors, NOD1, and NOD2 in Oral Epithelial Cells

Oral epithelium might be the first barrier against oral bacteria in periodontal tissue. We hypothesized that oral epithelium is endowed with innate immune receptors for bacterial components, which play roles in host defense against bacterial infection without being accompanied by excessive inflammatory responses. We found clear expression of Toll-like receptor (TLR)4 as well as TLR2, and strong expression of NOD1 and NOD2 in normal oral epithelial tissues by immunohistochemical analysis. We also showed that primary oral epithelial cells in culture expressed these molecules using PCR, flow cytometry, and immunostaining. In inflamed oral epithelium, cell-surface localizations of TLR2 and TLR4 were more clearly observed than in healthy tissue. Upon stimulation with synthetic ligands for these receptors, the expression of β-defensin 2 was markedly up-regulated. These findings indicate that these molecules in oral epithelial cells are functional receptors that induce antibacterial responses.

Diagnostic performance of MR imaging of three major salivary glands for Sjögren's syndrome

OBJECTIVE

We analyzed the diagnostic performance of the MR imaging findings of the parotid, submandibular, and sublingual glands to discriminate between patients with and without Sjögren's syndrome.

METHODS

We retrospectively analyzed the correlation between the MR imaging and histopathological findings obtained from 69 patients with clinically suspected Sjögren's syndrome. We evaluated the heterogeneous signal intensity distribution on T1- and T2-weighted images, the multiple high-signal-intensity spots on MR sialograms, and the volume of the parotid, submandibular, and sublingual salivary glands.

RESULTS

The multiple high-signal-intensity spots in the parotid gland showed the highest sensitivity and diagnostic accuracy (82% and 83%, respectively). In addition, the multiple high-signal-intensity spots and the heterogeneous signal intensity distribution in the submandibular gland showed high specificity (100% and 88%, respectively). The volume of the submandibular gland, but not that of the parotid or sublingual gland, was smaller in patients with Sjögren's syndrome.

CONCLUSIONS

The presence of multiple high-signal-intensity spots on an MR sialogram in the parotid gland should be considered the best diagnostic indicator for Sjögren's syndrome. The presence of spots, heterogeneity, and the change to smaller volumes in the submandibular gland were also helpful because of their high specificity, particularly in advanced cases.

Development of a compact ECR ion source for various ion production

There is a desire that a carbon-ion radiotherapy facility will produce various ion species for fundamental research. Although the present Kei2-type ion sources are dedicated for the carbon-ion production, a future ion source is expected that could provide: (1) carbon-ion production for medical use, (2) various ions with a charge-to-mass ratio of 1/3 for the existing Linac injector, and (3) low cost for modification. A prototype compact electron cyclotron resonance (ECR) ion source, named Kei3, based on the Kei series has been developed to correspond to the Kei2 type and to produce these various ions at the National Institute of Radiological Sciences (NIRS). The Kei3 has an outer diameter of 280 mm and a length of 1120 mm. The magnetic field is formed by the same permanent magnet as Kei2. The movable extraction electrode has been installed in order to optimize the beam extraction with various current densities. The gas-injection side of the vacuum chamber has enough space for an oven system. We measured dependence of microwave frequency, extraction voltage, and puller position. Charge state distributions of helium, carbon, nitrogen, oxygen, and neon were also measured.

Expression of umami-taste-related genes in the tongue: a pilot study for genetic taste diagnosis

OBJECTIVE

Expression of taste-related genes in the tongue was analysed to develop a technique for genetic diagnosis of umami taste disorders.

MATERIALS AND METHODS

Tissue samples were collected from healthy volunteers by scraping the foliate papillae of the tongue. Immunocytochemistry staining of gustducin, a taste-cell-specific G protein, and gene expression analysis by real-time polymerase chain reaction of β-actin, gustducin (GNAT3) and umami receptors (T1R1, T1R3 and mGluR1) were performed. Changes in umami receptor expression following application of umami substances onto the tongue were analysed.

RESULTS

Gustducin-positive cells were observed in the samples, indicating the presence of taste cells. Gene expression of β-actin, GNAT3, T1R1 and T1R3 was detected in all seven samples tested, while that of mGluR1 was detected in four samples. Sequence analysis by NCBI Blast showed that each polymerase chain reaction product had a 99% rate of identification of its target sequence. Stimulation of the tongue with monosodium glutamate significantly upregulated the gene expression levels of T1R1 and T1R3, indicating that this method can detect alterations in umami-related gene expression.

CONCLUSION

Evaluation of the expression of the umami receptor genes, T1R1 and T1R3, in the tongue may be clinically useful for objective genetic diagnosis of umami taste disorders.

FGF-2 stimulates periodontal regeneration: results of a multi-center randomized clinical trial

The efficacy of the local application of recombinant human fibroblast growth factor-2 (FGF-2) in periodontal regeneration has been investigated. In this study, a randomized, double-blind, placebo-controlled clinical trial was conducted in 253 adult patients with periodontitis. Modified Widman periodontal surgery was performed, during which 200 µL of the investigational formulation containing 0% (vehicle alone), 0.2%, 0.3%, or 0.4% FGF-2 was administered to 2- or 3-walled vertical bone defects. Each dose of FGF-2 showed significant superiority over vehicle alone (p < 0.01) for the percentage of bone fill at 36 wks after administration, and the percentage peaked in the 0.3% FGF-2 group. No significant differences among groups were observed in clinical attachment regained, scoring approximately 2 mm. No clinical safety problems, including an abnormal increase in alveolar bone or ankylosis, were identified. These results strongly suggest that topical application of FGF-2 can be efficacious in the regeneration of human periodontal tissue that has been destroyed by periodontitis.

High serum levels of IGF-I contribute to promotion of endochondral ossification in mandibular condyle and cause its specific elongation in acromegaly-like rats

Mandibular protrusion accompanies acromegaly or acrogigantism. To clarify the detailed mechanisms, we used an acromegaly-like rat model recently developed by exogenous administration of insulin-like growth factor I (IGF-I). Human recombinant IGF-I (640 microg/day) continuously was infused subcutaneously to 10-week-old male rats (n=12) for four weeks. Control, sham-operated animals (n=12) were injected with saline alone. Twelve rats (six from each group) were killed immediately after ending administration at age 14 weeks. Another 12 rats (six from each group) were housed for an additional four weeks after treatment ended. Mandibular condylar length increased significantly in the IGF-I rats compared with the control rats, but no significant intergroup difference was found in the lengths of the coronoid and angular processes. Cartilaginous layer width, bone matrix volume, and the number of osteoblasts in the mandibular condyle increased significantly in the IGF-I group. These histopathological changes in the condyle disappeared after IGF-I administration was discontinued; however, the morphological change in condylar length remained. These findings suggest that mandibular protrusion in patients with acromegaly or acrogigantism may be evoked by superfluous elongation of the mandibular condyle and that such elongation can be induced by endochondral ossification caused by high IGF-I serum levels.

Evaluation of the position, mobility, and morphology of the disc by MRI before and after four different treatments for temporomandibular joint disorders

OBJECTIVES

The purpose of this study was to evaluate changes in disc position, mobility, and morphology in patients with temporomandibular joint disorders (TMD) in response to four different treatments, splint therapy, pumping manipulation, arthrocentesis, and arthroscopic surgery, using magnetic resonance imaging (MRI).

METHODS

Eighty-five joints (85 patients) with unilateral internal derangement or osteoarthritis that were successfully treated were included in this study. The patients were divided into four groups as follows: splint therapy group, pumping manipulation group, arthrocentesis group, and arthroscopic surgery group. Changes in the disc position, mobility, and morphology before and after treatment were compared among the four groups using MRI.

RESULTS

All discs showed anterior disc displacement (ADD) without reduction before treatment. Only 10% of the joints became ADD with reduction after treatment, and the other joints remained ADD without reduction in spite of treatment. Discs treated by arthroscopic surgery were located more anteriorly compared with pre-treatment. In pre-treatment MRI, the rate of stuck disc increased as the stage of the treatment advanced. In post-treatment MRI, all temporomandibular joints (TMJs) had mobile discs. The disc deformity advanced after arthrocentesis and arthroscopic surgery.

CONCLUSIONS

Even though clinical signs and symptoms were alleviated by treatment, most discs remained ADD without reduction on MRI in spite of treatment. This suggests that the four treatments do not necessarily improve the position and deformity of the disc, and that arthroscopic surgery advances the deformity and anterior displacement of the disc. Disc mobility is important for improving clinical signs and symptoms.

Morphological and histopathological changes in tongues of experimentally developed acromegaly-like rats

An acromegaly-like rat model recently developed by exogenous administration of insulin-like growth factor I (IGF-I) was used to investigate morphological and histopathological tongue changes and clarify whether the changes were reversible. Human recombinant IGF-I (640 microg/day) was continuously subcutaneously infused into ten-week-old male rats for four weeks (IGF-I group; n = 6). Control sham-operated animals were injected saline alone (control group; n = 6). Rats were sacrificed immediately on ending administration at the age of fourteen weeks. Another 12 rats (6 from each group) were housed for an additional four weeks after administration ended. Total IGF-I (human + rat) increased significantly during administration, returning to control levels afterwards. Tongue weights significantly increased with histopathological changes present (increases in the muscle-bundle width, spaces between muscle-bundles and epithelium thickness) in the IGF-I group compared to control rats. Tongue size returned to control levels after discontinuation of IGF-I administration. These findings suggest that the characteristic tongue enlargement was developed experimentally in our acromegaly-like rat model, and that such morphological and histopathological tongue changes are reversible on normalization of circulating IGF-I levels.

Chemically synthesized pathogen-associated molecular patterns increase the expression of peptidoglycan recognition proteins via toll-like receptors, NOD1 and NOD2 in human oral epithelial cells

Peptidoglycan recognition proteins (PGRPs), a novel family of pattern recognition molecules (PRMs) in innate immunity conserved from insects to mammals, recognize bacterial cell wall peptidoglycan (PGN) and are suggested to act as anti-bacterial factors. In humans, four kinds of PGRPs (PGRP-L, -Ialpha, -Ibeta and -S) have been cloned and all four human PGRPs bind PGN. In this study, we examined the possible regulation of the expression of PGRPs in oral epithelial cells upon stimulation with chemically synthesized pathogen-associated molecular patterns (PAMPs) in bacterial cell surface components: Escherichia coli-type tryacyl lipopeptide (Pam3CSSNA), E. coli-type lipid A (LA-15-PP), diaminopimelic acid containing desmuramyl peptide (gamma-D-glutamyl-meso-DAP; iE-DAP), and muramyldipeptide (MDP). These synthetic PAMPs markedly upregulated the mRNA expression of the four PGRPs and cell surface expression of PGRP-Ialpha and -Ibeta, but did not induce either mRNA expression or secretion of inflammatory cytokines, in oral epithelial cells. Suppression of the expression of Toll-like receptor (TLR)2, TLR4, nucleotide-binding oligomerization domain (NOD)1 and NOD2 by RNA interference specifically inhibited the upregulation of PGRP mRNA expression induced by Pam3CSSNA, LA-15-PP, iE-DAP and MDP respectively. These PAMPs definitely activated nuclear factor (NF)-kappaB in the epithelial cells, and suppression of NF-kappaB activation clearly prevented the induction of PGRP mRNA expression induced by these PAMPs in the cells. These findings suggested that bacterial PAMPs induced the expression of PGRPs, but not proinflammatory cytokines, in oral epithelial cells, and the PGRPs might be involved in host defence against bacterial invasion without accompanying inflammatory responses.

Insulin-like growth factor-I stimulates acromegaly-like specific mandibular enlargement in rats

To help us investigate the time course of mandibular enlargement in acromegaly or acrogiantism to determine the most suitable period for occlusal treatment in this disease, our aim was to develop a rat model of acromegaly (acrogiantism). In this study, prominent mandibular enlargement was induced by continuous subcutaneous infusion of human recombinant insulin-like growth factor-I (IGF-I) (640 microg/day) in 10-week-old male rats for 4 weeks (n = 6); the control sham-operated group was injected with saline alone (n = 6). Circulating human IGF-I was clearly detectable in the IGF-I group during the four-week administration period, while endogenous rat IGF-I levels decreased. Total IGF-I (human + rat) increased significantly during administration, returning to control levels afterwards. The length of every bone examined (mandible, maxilla, and femur) showed a significant increase compared to control rats, especially the mandible. Although the mandible did not continue to grow after discontinuation of IGF-I administration, it did not return to control size, unlike the maxilla and femur, and disharmonious jaw size (between maxilla and mandible) persisted even after circulating IGF-I levels normalized. These findings in our rat model suggest that mandibular occlusal treatment should only be considered for acromegalic (acrogiantic) patients after serum IGF-I levels have normalized and bone growth has ceased.

Usefulness of heavily T(2) weighted magnetic resonance images for the differential diagnosis of parotid tumours

OBJECTIVES

To evaluate the usefulness of heavily T(2) weighted (T2W) magnetic resonance (MR) images for the differential diagnosis of parotid tumours.

METHODS

Conventional T2W and heavily T2W images obtained from 43 patients with parotid tumours were reviewed retrospectively. Tumours were classified pathologically into three types: pleomorphic adenoma (25 cases), Warthin's tumour (7 cases) and malignant tumour (11 cases). During interpretation of each MR image, special attention was paid to the homogeneity and signal intensity displayed by the solid portions of the tumours.

RESULTS

Heavily T2W images could distinguish pleomorphic adenoma from Warthin's tumour and malignant tumours based on the homogeneity and signal intensity of the solid portions, whereas conventional T2W images could not. On conventional T2W images, neither homogeneity nor signal intensity differed significantly among these three tumour types. On heavily T2W images, malignant and Warthin's tumours appeared more homogeneous than pleomorphic adenoma (P<0.0061); signal intensity from pleomorphic adenoma was significantly different to signal intensity from malignant tumours (P<0.05) and Warthin's tumour (P<0.005).

CONCLUSIONS

Heavily T2W MR images can be useful in distinguishing pleomorphic adenoma from Warthin's tumour and malignant tumours.

Platelet responses and anaphylaxis-like shock induced in mice by intravenous injection of whole cells of oral streptococci

Intravenous injection of lyophilized whole cells of various oral streptococcal strains into muramyldipeptide (MDP)-primed C3H/HeN mice induces rapid anaphylactoid shock. Here we examined the mechanism underlying this shock. In non-primed mice, Streptococcus intermedius K-213K (SiK213) and Streptococcus constellatus T21 (ScT21) produced little or no sign of shock. In MDP-primed mice, SiK213 caused lethal shock, while ScT21 only had a weak effect. SiK213 induced decreases in blood platelets and 5-hydroxytryptamine (5HT) preceding the shock, while the effects of ScT21 were weak. The SiK213-induced 5HT decrease and shock were reduced by a complement-C5 inhibitor. These results suggest that (i). streptococcal bacterial cells can induce rapid platelet responses, (ii). complement-dependent degradation of platelets may be involved in streptococcus-induced shock, (iii). the streptococcus-induced platelet degradation or degranulation may occur largely in the systemic circulation, and (iv). platelets may play a role not only in infectious diseases caused by gram-negative bacteria, but also in diseases caused by gram-positive bacteria.

A simple, yet accurate method for detecting and quantifying secretions from human minor salivary glands using the iodine-starch reaction

The lack of published information about the minor salivary glands is due in part to the difficulties experienced in collecting and quantifying their secretions. In fact, no method exists for measuring their secretions that is both simple and accurate. This investigation examined the accuracy of our newly developed method (which simply employs the iodine-starch reaction) in 10 healthy non-medicated adults. A strip painted with a solution of iodine in absolute alcohol then with a fine starch powder mixed with castor oil was placed at a designated location on the lower-lip mucosa for 2 min to collect saliva. Black-stained spots of various sizes corresponding to the individual glands could be accurately visualized. After removal of the strip, the total stained area (mm2) was calculated by digitizing the spot areas using a computer system. The correlation coefficient (r) between known volumes of saliva and stain size was 0.995, indicating a close correlation. The correlation coefficient (r) between area values obtained in the first trial in each subject (Y) and the second (X; 10 min later) was 0.963, and the simple regression equation was close to Y=X, indicating good reproducibility. The mean flow rate microl/cm2 per min) obtained by converting mean total area to volume and thence to flow rate was 0.49+/-0.26, in good agreement with published values obtained by others. These results suggest that our newly developed method allows both the distribution and secretion rate of the minor salivary glands to be observed, and that it should be of practical value due to its simplicity, accuracy, and reproducibility.

Centrally mediated reflex vasodilation in the gingiva induced by painful tooth-pulp stimulation in sympathectomized human subjects

This study was designed to determine whether painful electrical stimulation of the tooth pulp induces centrally mediated reflex vasomotor changes in human gingiva and whether the sympathetic nervous system is involved in the vasomotor responses. Dynamic changes in maxillary gingival blood flow (GBF) following painful electrical stimulation of the mandibular lateral incisor were investigated, by means of laser-Doppler flowmetry, in both healthy volunteers and patients undergoing sympathetic blockade for hyperhidrosis. Increases in GBF were observed in both healthy volunteers and patients on the ipsilateral side without an increase in systemic blood pressure, but the evoked GBF increase disappeared when pain sensation was abolished by local anesthetization with 2% xylocaine solution. The vasodilator responses did not differ in amplitude between before and after the sympathectomy. These results suggest that painful tooth stimulation evokes centrally mediated reflex vasodilation, presumably via parasympathetic efferent fibers, in the human gingiva and that sympathetic vasomotor mechanisms are not involved in these responses.

Dependence of pulpal blood-flow responses on baseline blood-flow in the cat

It has been shown earlier that electrical stimulation of the distal cut end of the inferior alveolar nerve (IAN) in the cat evokes three different patterns of pulpal blood-flow (PBF) response in the ipsilateral mandibular canine tooth (a decrease, a biphasic response, or an increase). The response to a given stimulus sometimes changed to another pattern even in one and the same experimental animal during the course of the experiment. It is known that the evoked decrease is due to activation of the sympathetics and that the increase is due to antidromic activation of sensory fibres; but, it is unknown why the response varies so much. It is hypothesised that the baseline blood-flow (BBF) modulates vasomotor responses in the dental pulp. To test this hypothesis, the effects of BBF on PBF responses elicited by the IAN stimulation mentioned above were investigated. Dynamic changes in PBF in cat mandibular canine teeth were elicited by electrical stimulation of the distal cut end of the IAN, at various BBF, with blood-flow monitored by laser Doppler flowmetry. The amplitude of the PBF vasodilator response increased as BBF was adjusted downwards (by cooling the tooth). In contrast, the amplitude of the PBF vasoconstrictor response increased as the BBF rose. Vasodilator responses could be transformed into vasoconstrictor responses, and vice versa, by alterations in the BBF. No systemic blood-pressure changes were elicited throughout the experiment. These results indicate that a consideration of baseline vascular tone is important, whenever the size of PBF responses to various stimuli is discussed or calculated.

Evaluation of pulse sequences used for magnetic resonance sialography

OBJECTIVES

To determine the most appropriate sequences for the visualization of small parotid ducts in MR sialography.

METHODS

MR images of a phantom consisting of distilled water in polyethylene tubes were obtained with turbo-spin echo (TSE), single-shot turbo-spin echo (SSTSE), half-fourier acquisition, single-shot turbo-spin echo (HASTE) and turbo gradient-spin echo (TGSE) pulse sequences and compared visually and quantitatively. MR sialograms obtained from healthy volunteers and patients with Sjögren's syndrome (SS) were obtained using the same four sequences.

RESULTS

In the phantom, TSE images were best and the contrast-noise ratio (CNR) highest. In the volunteers, the main ducts were especially clearly visualized with TSE and in SSTSE; however, the majority of secondary and/or tertiary parotid ducts were not depicted by any of the sequences used. In SS patients, images of small main ducts and small pseudocysts were clearer using TSE. However, TSE could not depict the narrow main ducts or peripheral ducts or very small pseudocysts.

CONCLUSIONS

TSE is considered the most suitable MR sequence for assessing small parotid gland ducts. However, further improvement is needed since it does not always visualize them sufficiently.

Catheter ablation of idiopathic left ventricular tachycardia with multiple breakthrough sites guided by an electroanatomical mapping system

Idiopathic ventricular tachycardia (VT) has been considered to be amenable to radiofrequency catheter ablation guided by Purkinje potentials. However, there appear to be various types of reentrant circuits associated with this VT deduced from the results of the successful radiofrequency catheter ablation cases. We describe in this report a patient with idiopathic left ventricular tachycardia which was electrically inducible and verapamil sensitive. Multiple earliest ventricular activation sites during tachycardia were detected with electroanatomical mapping using the CARTO system. Multiple applications at these sites failed to eliminate the VT. The earliest Purkinje potential was recorded at least 1.5 cm away from the earliest ventricular activation sites, and the radiofrequency current application at this site resulted in the complete abolition of this VT. The reentrant circuit of this tachycardia seemed to have multiple breakthrough sites to the ventricular myocardium, which were distant from the requisite part of the reentrant circuit of this VT involving the Purkinje fiber network conduction system.

Serious arrhythmias in patients with apical hypertrophic cardiomyopathy

We report cases of serious arrhythmias associated with apical hypertrophic cardiomyopathy (AHCM). Thirty-one patients were referred to our institute to undergo further assessment of their AHCM from 1988 to 1999. Three patients with nonsustained ventricular tachycardia demonstrated an 123I-MIBG regional reduction in the tracer uptake. In two patients with ventricular fibrillation (VF), the findings from 123I-MIBG imaging revealed regional sympathetic denervation in the inferior and lateral regions. Electrophysiologic study demonstrated reproducible induction of VF in aborted sudden death and presyncopal patients, resulting in the need for an implantable defibrillator device and amiodarone in each patient. Patients with refractory atrial fibrillation with a rapid ventricular response suffered from serious congestive heart failure. A prudent assessment and strategy in patients with this disease would be indispensable in avoiding a disastrous outcome.

Low-dose continuous indomethacin in early days of age reduce the incidence of symptomatic patent ductus arteriosus without adverse effects

We conducted a comparative study to evaluate whether the low-dose continuous indomethacin therapy in the early days of age would reduce incidence of the symptomatic patent ductus arteriosus (PDA) without the adverse effects. Thirty-seven infants were in the historical comparison group, and 39 infants were given low-dose indomethacin continuously (0.004 mg/kg/h) from 6-12 postnatal hours until the recognition of closing PDA. Low-dose continuous indomethacin significantly decreased the incidence of symptomatic PDA at 5 days of age (p < 0.01) as compared with the historical comparison group. There was no episode of decreasing urinary output and necrotizing enterocolitis in the indomethacin group. We conclude that the low-dose continuous indomethacin therapy results in decreasing the incidence of symptomatic PDA without significant adverse reactions.

Diastolic potentials observed in idiopathic left ventricular tachycardia

Radiofrequency catheter ablation (RF-CA) has demonstrated a high success rate in eliminating idiopathic left ventricular tachycardia (ILVT), and the target site is determined by the score of pace mapping or the Purkinje potential (PP) preceding the onset of the ventricular activation, which is considered to indicate the exit site of the reentrant circuit. However, only a few reports have described the potential obtained from the slow conduction zone. RF-CA was successfully performed in 8 patients with ILVT. Careful mapping of the left ventricle during tachycardia was carried out to find the diastolic potential (DP). A DP was obtained in 4 patients (group 1), but not in 4 others (group 2). The local electrogram was recorded from the distal tip of the ablation catheter during the RF current application in order to investigate the pattern of termination of ILVT. A DP was recorded at the point where the catheter was slightly pulled back to a site proximal to the exit site of the reentrant circuit at the left interventricular basal septum. In group 1, conduction block between the DP and PP eliminated ILVT in 3 out of 4 cases, and 1 case showed conduction block between the DP and ventricular potential. In 2 out of 4 patients in group 2, the local electrogram showed conduction block between PP and the ventricular potential when VT terminated. The ablation site in group 1 was located relatively more basal than that in group 2 in anatomy. A DP was obtained in a half of the cases with ILVT and RF-CA at this site could eliminate ILVT. A DP was obtained at a site relatively basal to the exit of the reentrant circuit and it is considered that this is a useful marker in terms of the successful ablation of ILVT.