A systematic algorithm for large-bore arterial access closure after TAVI: the TAVI-MultiCLOSE study

BACKGROUND

Despite transcatheter aortic valve implantation (TAVI) having become a routine procedure, access site bleeding and vascular complications are still a concern which contribute to procedure-related morbidity and mortality.

AIMS

The TAVI-MultiCLOSE study aimed to assess the safety and efficacy of a new vascular closure algorithm for percutaneous large-bore arterial access closure following transfemoral (TF)-TAVI.

METHODS

All consecutive TF-TAVI cases in which the MultiCLOSE vascular closure algorithm was used were prospectively included in a multicentre, observational study. This stepwise algorithm entails the reinsertion of a 6-8 Fr sheath (primary access) following the initial preclosure with one or two suture-based vascular closure devices (VCDs). This provides the operator with the opportunity to perform a quick and easy angiographic control and tailor the final vascular closure with either an additional suture- or plug-based VCD, or neither of these.

RESULTS

Among 630 patients who underwent TF-TAVI utilising the MultiCLOSE algorithm, complete arterial haemostasis was achieved in 616 patients (98%). VCD failure occurred in 14 patients (2%), treated with either balloon inflation (N=1), covered stent (N=12) or surgical repair (N=1). Overall, this vascular closure approach resulted in a minor and major vascular complication rate of 2.2% and 0.6%, respectively. At 30 days, only one new minor vascular complication (0.2%) was noted. In-hospital and 30-day all-cause mortality rates were 0.2% and 1.0%, respectively.

CONCLUSIONS

Use of the MultiCLOSE vascular closure algorithm was demonstrated to contribute to an easy, safe, efficacious and durable vascular closure after TF-TAVI, resulting in a major vascular complication rate of less than 1%.

iFR/FFR/IVUS Discordance and Clinical Implications: Results From the Prospective Left Main Physiology Registry

OBJECTIVES

This study aimed to assess discordance between results of instantaneous wave-free ratio (iFR), fractional flow reserve (FFR), and intravascular ultrasound (IVUS) in intermediate left main coronary (LM) lesions, and its impact on clinical decision making and outcome.

METHODS

We enrolled 250 patients with a 40%-80% LM stenosis in a prospective, multicenter registry. These patients underwent both iFR and FFR measurements. Of these, 86 underwent IVUS and assessment of the minimal lumen area (MLA), with a 6 mm2 cutoff for significance.

RESULTS

Isolated LM disease was recognized in 95 patients (38.0%), while 155 patients (62.0%) had both LM disease and downstream disease. In 53.2% of iFR+ and 56.7% of FFR+ LM lesions, the measurement was positive in only one daughter vessel. iFR/FFR discordance occurred in 25.0% of patients with isolated LM disease and 36.2% of patients with concomitant downstream disease (P=.049). In patients with isolated LM disease, discordance was significantly more common in the left anterior descending artery and younger age was an independent predictor of iFR-/FFR+ discordance. iFR/MLA and FFR/MLA discordance occurred in 37.0% and 29.4%, respectively. Within 1 year of follow-up, major cardiac adverse events (MACE) occurred in 8.5% and 9.7% (P=.763) of patients whose LM lesion was deferred or revascularized, respectively. Discordance was not an independent predictor of MACE.

CONCLUSIONS

Current methods of estimating LM lesion significance often yield discrepant findings, complicating therapeutic decision-making.

Impact of routine use of a cerebral protection device on the TAVR procedure and its short-term outcomes: a single-centre experience

BACKGROUND

Stroke is a major concern in transcatheter aortic valve replacement (TAVR). The introduction of a cerebral protection devices may counteract the evolution towards minimally invasive TAVR. At this time, there is insufficient data to support the routine use of these devices.

METHODS

We aimed to evaluate the outcome of the routine use of the Sentinel Cerebral protection system^® (CPS) in patients undergoing TAVR, after completing a CT-based screening process for feasibility of Sentinel implantation. We report our initial experience with the routine implementation of the Sentinel CPS in all anatomically suitable patients undergoing TAVR. We retrospectively compared the procedural characteristics and outcomes between all TAVR patients treated with (n = 78) and without (n = 79) intended Sentinel.

RESULTS

The Sentinel CPS could successfully be deployed in 99% of intended cases after CT feasibility screening. TAVR procedures with Sentinel CPS were not longer than procedures without Sentinel use (89 ± 20 versus 120 ± 50 min, p = 0.007). Sentinel CPS use was not associated with an increased risk of procedural complications. Stroke was observed in none (0%) of the Sentinel CPS patients, and in 6.3% of the non-Sentinel CPS patients (p = 0.05). The finding of stroke was associated with a high risk of early postprocedural mortality: 60% of stroke patients died within 3 months.

CONCLUSION

Routine use of the Sentinel CPS in CT-screened TAVR patients is feasible with high procedural success, without significant adverse events and without counteracting the evolution towards minimally invasive TAVR. Clinically relevant stroke was observed in none of the Sentinel CPS patients.

SPECT-CCTA: guiding treatment in ischaemic heart disease

Combining myocardial perfusion single photon emission computed tomography (SPECT-MPI) and coronary computed tomography angiography (CCTA) is an interesting hybrid imaging option in modern cardiovascular medicine. The integrated hybrid technique has a number of advantages compared to visual side-by-side analysis of the separate modalities. CT attenuation map can correct for attenuation artefacts and thus improve the diagnostic accuracy of SPECT-MPI. Moreover, the anatomical information of the CCTA and the perfusion map of SPECT-MPI allow for vessel-based correlation and culprit vessel identification. Combining SPECT-MPI with CCTA is an appealing tool in the work-up of complex ischaemic heart disease and might help determine the optimal treatment strategy. This case series illustrates the role of SPECT-CCTA in decision-making of revascularization strategy in complex ischaemic heart disease.

Impact of COVID-19-related public containment measures on the ST elevation myocardial infarction epidemic in Belgium: a nationwide, serial, cross-sectional study

AIMS

The current study assessed the impact of COVID-19-related public containment measures (i.e. lockdown) on the ST elevation myocardial infarction (STEMI) epidemic in Belgium.

METHODS AND RESULTS

Clinical characteristics, reperfusion therapy modalities, COVID-19 status and in-hospital mortality of consecutive STEMI patients who were admitted to Belgian hospitals for percutaneous coronary intervention (PCI) were recorded during a three-week period starting at the beginning of the lockdown period on 13 March 2020. Similar data were collected for the same time period for 2017-2019. An evaluation of air quality revealed a 32% decrease in ambient NO₂ concentrations during lockdown (19.5 µg/m³ versus 13.2 µg/m³, p < .001). During the three-week period, there were 188 STEMI patients admitted for PCI during the lockdown versus an average 254 STEMI patients before the lockdown period (incidence rate ratio = 0.74, p = .001). Reperfusion strategy was predominantly primary PCI in both time periods (96% versus 95%). However, there was a significant delay in treatment during the lockdown period, with more late presentations (>12 h after onset of pain) (14% versus 7.6%, p = .04) and with longer door-to-balloon times (median of 45 versus 39 min, p = .02). Although the in-hospital mortality between the two periods was comparable (5.9% versus 6.7%), 5 of the 7 (71%) COVID-19-positive STEMI patients died.

CONCLUSION

The present study revealed a 26% reduction in STEMI admissions and a delay in treatment of STEMI patients. Less exposure to external STEMI triggers (such as ambient air pollution) and/or reluctance to seek medical care are possible explanations of this observation.

Repeating noninvasive risk stratification improves prediction of outcome in ICD patients

Background

Noninvasive risk stratification aims to detect abnormalities in the pathophysiological mechanisms underlying ventricular arrhythmias. We studied the predictive value of repeating risk stratification in patients with an implantable cardioverter‐defibrillator (ICD).

Methods

The EUTrigTreat clinical study was a prospective multicenter trial including ischemic and nonischemic cardiomyopathies and arrhythmogenic heart disease. Left ventricular ejection fraction ≤40% (LVEF), premature ventricular complexes >400/24 hr (PVC), non‐negative microvolt T‐wave alternans (MTWA), and abnormal heart rate turbulence (HRT) were considered high risk. Tests were repeated within 12 months after inclusion. Adjusted Cox regression analysis was performed for mortality and appropriate ICD shocks.

Results

In total, 635 patients had analyzable baseline data with a median follow‐up of 4.4 years. Worsening of LVEF was associated with increased mortality (HR 3.59, 95% CI 1.17–11.04), as was consistent abnormal HRT (HR 8.34, 95%CI 1.06–65.54). HRT improvement was associated with improved survival when compared to consistent abnormal HRT (HR 0.10, 95%CI 0.01–0.82). For appropriate ICD shocks, a non‐negative MTWA test or high PVC count at any moment was associated with increased arrhythmic risk independent of the evolution of test results (worsening: HR 3.76 (95%CI 1.43–9.88) and HR 2.50 (95%CI 1.15–5.46); improvement: HR 2.80 (95%CI 1.03–7.61) and HR 2.45 (95%CI 1.07–5.62); consistent: HR 2.47 (95%CI 0.95–6.45) and HR 2.40 (95%CI 1.33–4.33), respectively). LVEF improvement was associated with a lower arrhythmic risk (HR 0.34, 95%CI 0.12–0.94).

Conclusions

Repeating LVEF and HRT improved the prediction of mortality, whereas stratification of ventricular arrhythmias may be improved by repeating LVEF measurements, MTWA and ECG Holter monitoring.

Clinical outcomes of bioresorbable vascular scaffolds implanted with routine versus selective optical coherence tomography guidance: results from a single-centre experience

AIMS

We aimed to investigate the effects of an initial learning period with mandatory optical coherence tomography (OCT) guidance for the implantation of everolimus-eluting bioresorbable vascular scaffolds (BVS).

METHODS AND RESULTS

We analysed procedural and clinical outcomes of all BVS implantations at a single centre where OCT guidance was mandatory in the initial rollout (OCT-mandatory) phase. We compared these data with the later phase where use of OCT was at operator discretion (OCT-selective or angiography). We implanted 406 BVS in 306 vessels (201 OCT, 105 angiography) in 272 patients. Follow-up duration was 38±10 months. Annualised rates of device-oriented cardiac events (DOCE) and scaffold thrombosis (ScT) were 1.4% and 0.4%, respectively. The risks of DOCE (HR 1.06, 95% CI: 0.33-3.34; p=0.71) and ScT (HR 0.48, 95% CI: 0.07-3.85; p=0.49) were not significantly different when comparing the OCT and angiography groups.

CONCLUSIONS

Routine use of OCT to guide and optimise BVS implants results in very acceptable outcomes. Further, the benefits of such an early OCT-mandatory "learning" period persist after cessation of routine OCT usage when imaging is not routinely used. A period of mandatory OCT usage for BVS implants may therefore be beneficial in improving patient outcomes with these devices.

From debulking to delivery: sequential use of rotational atherectomy and Guidezilla™ for complex saphenous vein grafts intervention

Background

Percutaneous coronary interventions (PCI) of old calcified saphenous vein grafts (SVGs) is challenging and is associated with a considerably high risk of adverse ischemic events in the short- and long-term as compared to native coronary arteries. We report a case in which a non-dilatable, calcified SVG lesion is successfully treated with rotational atherectomy followed by PCI and stenting with local stent delivery (LSD) technique using the Guidezilla™ guide extension catheter (5-in-6 Fr) in the “child-in-mother” fashion.

Case presentation

A 70 years-old man with a dilated ischemic cardiomyopathy, triple coronary artery bypass grafting (CABG) in 1990 and chronic renal failure (baseline GFR: 45 ml/min/1.73 m²) underwent a coronary angiography for a Non-ST segment elevation myocardial infarction (NSTEMI). Native coronary circulation was completely occluded at the proximal segments. Grafts angiography showed a tandem calcified lesions of SVG on distal right coronary artery (RCA) and an ostial stenosis of the SVG on first obtuse marginal branch (OM1). Left internal mammary artery on the mid left anterior descending artery was patent. Ad Hoc PCI of SVG on RCA was attempted. The proximal calcified stenosis has been crossed with a 1.5 x 12 mm balloon only with the support of Guidezilla™, however the non-compliant (NC) balloon 2.5 x 15 mm was unable to break the hard and calcified plaque. After several attempts, the procedure was interrupted with a suboptimal result. An elective transradial PCI of SVG on RCA with rotational atherectomy was performed. Two runs with 1.25 mm burr and 2 runs with 1.5 mm burr were carried out. Then, the use of distal anchoring balloon warranted support and tracking, made as centring rail for the advance of the tip of the “mother-and-child” catheter into the SVG. During slow deflation of the balloon, the Guidezilla™ was advanced distal to the stenoses to be stented, thus allowing the placement of two long drug eluting stents according to a LSD technique.

Conclusions

Rotational atherectomy is a feasible option for non-dilatable stenoses in old SVGs when there is no evidence of thrombus or vessel dissection and the subsequent use of “mother-and-child” catheter has a key role, especially in case of radial approach, for long stents delivery.

Visual and Quantitative Assessment of Coronary Stenoses at Angiography Versus Fractional Flow Reserve: The Impact of Risk Factors

BACKGROUND

The correlation between angiographic assessment of coronary stenoses and fractional flow reserve (FFR) is weak. Whether and how risk factors impact the diagnostic accuracy of angiography is unknown. We sought to evaluate the diagnostic accuracy of angiography by visual estimate and by quantitative coronary angiography when compared with FFR and evaluate the influence of risk factors (RF) on this accuracy.

METHODS AND RESULTS

In 1382 coronary stenoses (1104 patients), percent diameter stenosis by visual estimation (DS_VE) and by quantitative coronary angiography (DS_QCA) was compared with FFR. Patients were divided into 4 subgroups, according to the presence of RFs, and the relationship between DS_VE, DS_QCA, and FFR was analyzed. Overall, DS_VE was significantly higher than DS_QCA (P<0.0001); nonetheless, when examined by strata of DS, DS_VE was significantly smaller than DS_QCA in mild stenoses, although the reverse held true for severe stenoses. Compared with FFR, a large scatter was observed for both DS_VE and DS_QCA. When using a dichotomous FFR value of 0.80, C statistic was significantly higher for DS_VE than for DS_QCA (0.712 versus 0.640, respectively; P<0.001). C statistics for DS_VE decreased progressively as RFs accumulated (0.776 for ≤1 RF, 0.750 for 2 RFs, 0.713 for 3 RFs and 0.627 for ≥4 RFs; P=0.0053). In addition, in diabetics, the relationship between FFR and angiographic indices was particularly weak (C statistics: 0.524 for DS_VE and 0.511 for DS_QCA).

CONCLUSIONS

Overall, DS_VE has a better diagnostic accuracy than DS_QCA to predict the functional significance of coronary stenosis. The predictive accuracy of angiography is moderate in patients with ≤1 RFs, but weakens as RFs accumulate, especially in diabetics.

Introducing ICD-resistant mortality as an end point to evaluate the clinical efficacy of an implantable cardioverter-defibrillator in ischaemic cardiomyopathy

OBJECTIVE

A new end point called ICD-resistant mortality was evaluated to assess the clinical efficacy of ICD implantations.

METHODS AND RESULTS

In 302 ICD patients with ischaemic cardiomyopathy, we investigated which clinical parameters predicted useful ICD implantations using cumulative incidence competing risk analysis. Implantation was deemed clinically useful when the ICD provided appropriate therapy and the patient survived implantation by 1 year and the first shock by 30 days. ICD-resistant mortality (ICDRM) was defined as death within 30 days after the first shock, within 1 year of implantation or without previous appropriate ICD therapy. After 5 years, ICDRM occurred in 23% of implantations, while 36% were clinically useful. After multivariable analysis, ICDRM was associated with LVEF <35% (HR: 2.63; p = .005), beta-blocker dose <50% (HR: 2.0; p = .01) and anterior or diffuse infarct location (HR: 3.61; p = .001 and HR: 2.89; p = .02). Useful ICD implantations were associated with beta-blocker dose <50% (HR: 1.64; p = .02) and non-anterior infarct location (HR: 3.22 vs anterior and 1.59 vs diffuse; combined p<.001).

CONCLUSIONS

Five years after implantation, an ICD could be classified as useful in 1 out of 3, while ICDRM occurred in one out of four patients. At 10 years, up to 80% of implantations could be categorized. Lower LVEF was related with significantly higher incidence of ICDRM. Anterior infarcts were associated with more ICDRM and less useful implantations than non-anterior infarcts. Future risk stratification for ICD should focus more on the discrimination between arrhythmic risk, probably preventable by ICDs and ICD-resistant mortality risk.

Saline-Induced Coronary Hyperemia

Background—

During thermodilution-based assessment of volumetric coronary blood flow, we observed that intracoronary infusion of saline increased coronary flow. This study aims to quantify the extent and unravel the mechanisms of saline-induced hyperemia.

Methods and Results—

Thirty-three patients were studied; in 24 patients, intracoronary Doppler flow velocity measurements were performed at rest, after intracoronary adenosine, and during increasing infusion rates of saline at room temperature through a dedicated catheter with 4 lateral side holes. In 9 patients, global longitudinal strain and flow propagation velocity were assessed by transthoracic echocardiography during a prolonged intracoronary saline infusion. Taking adenosine-induced maximal hyperemia as reference, intracoronary infusion of saline at rates of 5, 10, 15, and 20 mL/min induced 6%, 46%, 111%, and 112% of maximal hyperemia, respectively. There was a close agreement of maximal saline- and adenosine-induced coronary flow reserve (intraclass correlation coefficient, 0.922; P <0.001). The same infusion rates given through 1 end hole (n=6) or in the contralateral artery (n=6) did not induce a significant increase in flow velocity. Intracoronary saline given on top of an intravenous infusion of adenosine did not further increase flow. Intracoronary saline infusion did not affect blood pressure, systolic, or diastolic left ventricular function. Heart rate decreased by 15% during saline infusion ( P =0.021).

Conclusions—

Intracoronary infusion of saline at room temperature through a dedicated catheter for coronary thermodilution induces steady-state maximal hyperemia at a flow rate ≥15 mL/min. These findings open new possibilities to measure maximal absolute coronary blood flow and minimal microcirculatory resistance.

Intracoronary Adenosine: Dose-Response Relationship With Hyperemia

OBJECTIVES

The present study sought to establish the dosage of intracoronary (IC) adenosine associated with minimal side effects and above which no further increase in flow can be expected.

BACKGROUND

Despite the widespread adoption of IC adenosine in clinical practice, no wide-ranging, dose-response study has been conducted. A recurring debate still exists regarding its optimal dose.

METHODS

In 30 patients, Doppler-derived flow velocity measurements were obtained in 10 right coronary arteries (RCAs) and 20 left coronary arteries (LCAs) free of stenoses >20% in diameter. Flow velocity was measured at baseline and after 8 ml bolus administrations of arterial blood, saline, contrast medium, and 9 escalating doses of adenosine (4 to 500 μg). The hyperemic value was expressed in percent of the maximum flow velocity reached in a given artery (Q/Qmax, %).

RESULTS

Q/Qmax did not increase significantly beyond dosages of 60 μg for the RCA and 160 μg for LCA. Heart rate did not change, whereas mean arterial blood pressure decreased by a maximum of 7% (p < 0.05) after bolus injections of IC adenosine. The incidence of transient A-V blocks was 40% after injection of 100 μg in the RCA and was 15% after injection of 200 μg in the LCA. The duration of the plateau reached 12 ± 13 s after injection of 100 μg in the RCA and 21 ± 6 s after the injection of 200 μg in the LCA. A progressive prolongation of the time needed to return to baseline was observed. Hyperemic response after injection of 8 ml of contrast medium reached 65 ± 36% of that achieved after injection of 200 μg of adenosine.

CONCLUSIONS

This wide-ranging, dose-response study indicates that an IC adenosine bolus injection of 100 μg in the RCA and 200 μg in the LCA induces maximum hyperemia while being associated with minimal side effects.

Changes in Implantation Patterns and Therapy Rates of Implantable Cardioverter Defibrillators over Time in Ischemic and Dilated Cardiomyopathy Patients

BACKGROUND

Clinical guidelines on implantable cardioverter defibrillator (ICD) therapy changed significantly in the last decades with potential inherent effects on therapy efficacy. We aimed to study therapy rates in time and the association between therapies and mortality.

METHODS

All patients receiving an ICD, primary and secondary prevention, were included in a single-center retrospective registry. Information on first appropriate and inappropriate therapies was documented. Dates of implant were divided in P1: 1996-2001, P2: 2002-2008, and P3: 2009-2014.

RESULTS

A total of 727 patients, 84.9% male-66.4% ischemic cardiomyopathy (ICM)-56% primary prevention-mean follow-up 5.2 ± 4.1 years, were included. There was a shift from secondary to primary prevention indications, from ischemic to non-ICM, and from single chamber to cardiac resynchronization therapy defibrillator devices. The annual 1- and 3-year appropriate shock (AS) rate declined from 29.4% and 15.1% in P1, over 13.3% and 9.2% in P2 to 7.8% and 5.7% in P3 (log-rank P < 0.001), while inappropriate shock (IAS) rates remained unchanged (log-rank P = 0.635). After multivariate regression analysis a higher age at implant, lower left ventricular ejection fraction, history of stroke, diabetes mellitus, intake of loop diuretics or digitalis, higher creatinine, and longer QTc were independent predictors of mortality.

CONCLUSION

These changes in clinical practice with a shift to primary prevention and rise in non-ICM implants caused a significant decrease in AS incidence, while IAS remained stable. Receiving AS or IAS was not an independent predictor of mortality in our real-life cohort.

The Rise and Fall of Routine Manual Thrombectomy for ST-Elevation Myocardial Infarction

Manual thrombectomy (MT) with an aspiration catheter is frequently used in primary percutaneous coronary intervention (PPCI) for acute myocardial infarction with ST-segment elevation (STEMI). It is used to reduce the thrombus burden and the risk of no-reflow in the infarct related artery. This article summarises a chronological overview of the available evidence for its routine use in PPCI. An early series of small randomised controlled trials (RCTs) have shown a benefit of PPCI with MT over percutaneous coronary intervention alone, mainly when considering intermediate endpoints reflecting myocardial reperfusion. However, a recent series of large multicentre RCTs failed to corroborate the initial enthusiasm for MT, showing no improved benefit on hard endpoints such as mortality when compared with PPCI without MT. Furthermore, the largest RCT to date raised safety concerns after reporting an increased stroke risk after MT. We review the background, value, and implications of the current evidence before concluding that the routine use of MT in PPCI for STEMI should not be encouraged.

T-Wave Alternans Is Linked to Microvascular Obstruction and to Recurrent Coronary Ischemia After Myocardial Infarction

The purpose of this study is to investigate the relationship between T-wave alternans (TWA), infarct size and microvascular obstruction (MVO) and recurrent cardiac morbidity after ST elevation myocardial infarction (STEMI). One hundred six patients underwent TWA testing 1-12 months and 57 patients underwent cardiac magnetic resonance imaging (MRI) in the first 2-4 days after STEMI. During follow-up (3.5 ± 0.5 years), death (n = 2), ventricular tachycardia (n = 3), supraventricular tachycardia (n = 4), heart failure (n = 3) and recurrent coronary ischemia (n = 25) were observed. After multivariate analysis, positive TWA (HR2.59, CI1.10-6.11, p0.024) and larger MVO (HR1.08, CI1.01-1.16, p0.034) were associated with recurrent angina or ACS. Presence of MVO was correlated with TWA (Spearman rho 0.404, p0.002) and the impairment of LVEF (-0.524, p < 0.001). Patients after STEMI remain at a high risk of symptoms of coronary ischemia. The presence of MVO and TWA 1-12 months after STEMI is related to each other and to recurrent angina or ACS.

Heart rate turbulence predicts ICD-resistant mortality in ischaemic heart disease

AIMS

In high-risk patients, implantable cardioverter-defibrillators (ICDs) can convert the mode of death from arrhythmic to pump failure death. Therefore, we introduced the concept of 'ICD-resistant mortality' (IRM), defined as death (a) without previous appropriate ICD intervention (AI), (b) within 1 month after the first AI, or (c) within 1 year after the initial ICD implantation. Implantable cardioverter-defibrillator implantation in patients with a high risk of IRM should be avoided.

METHODS AND RESULTS

Implantable cardioverter-defibrillator patients with ischaemic heart disease were included if a digitized 24 h Holter was available pre-implantation. Demographic, electrocardiographic, echocardiographic, and 24 h Holter risk factors were collected at device implantation. The primary endpoint was IRM. Cox regression analyses were used to test the association between predictors and outcome. We included 130 patients, with a mean left ventricular ejection fraction (LVEF) of 33.6 ± 10.3%. During a follow-up of 52 ± 31 months, 33 patients died. There were 21 cases of IRM. Heart rate turbulence (HRT) was the only Holter parameter associated with IRM and total mortality. A higher New York Heart Association (NYHA) class and a lower body mass index were the strongest predictors of IRM. Left ventricular ejection fraction predicted IRM on univariate analysis, and was the strongest predictor of total mortality. The only parameter that predicted AI was non-sustained ventricular tachycardia.

CONCLUSION

Implantable cardioverter-defibrillator implantation based on NYHA class and LVEF leads to selection of patients with a higher risk of IRM and death. Heart rate turbulence may have added value for the identification of poor candidates for ICD therapy. Available Holter parameters seem limited in their ability to predict AI.

Can body surface microvolt T-wave alternans distinguish concordant and discordant intracardiac alternans?

INTRODUCTION

There is convincing experimental evidence that cellular action potential duration (APD) alternans is arrhythmogenic but its relationship with body surface microvolt T-wave alternans (MTWA) remains unclear. We investigated the relationship between MTWA and APD alternans induced by alternating cycle length (CL) pacing in a pig model.

METHODS

In 10 pigs, catheters in the right atrium (RA) and right (RV) and left ventricle (LV) allowed pacing and recording of monophasic action potentials (MAP). During RA pacing at stable 500-ms CL, LV was paced at alternating CL (505 ms and 495 ms). Changing the alternating LV (A-LV) pacing delay changes the size of the region with alternating ventricular activation. Spectral analysis of intracardiac MAP was correlated with body surface MTWA. In a similar setup (during alternating pacing in RV and LV), we investigated concordant versus discordant APD alternans.

RESULTS

Pacing the LV with subtle alternating cycle lengths at short A-LV delay leads to broad QRS (97 ± 10 ms), body surface MTWA (mean Valt 4.2 ± 1.8 µV), and positive RR-interval alternans. At longer A-LV delay, not resulting in QRS widening (68 ± 5 ms), body surface RR alternans was absent but MTWA remained detectable and was even more pronounced (8.7 ± 5.1 µV, P < 0.01). During both concordant and discordant pacing MTWA was present. The precordial leads were better for detecting discordant APD alternans (8.0 ± 2.9 µV and 12.8 ± 4.52 µV, P = 0.02).

CONCLUSION

MTWA is a potent technique to detect subtle and isolated intracardiac APD alternans that is artificially induced by alternating pacing. In the same model, discordant activation alternans can only be discriminated from concordant when using a quantifying approach of MTWA analysis.

T-wave alternans and beat-to-beat variability of repolarization: pathophysiological backgrounds and clinical relevance

In this review, we focus on temporal variability of cardiac repolarization. This phenomenon has been related to a higher risk for ventricular arrhythmia and is therefore interesting as a marker of sudden cardiac death risk. We review two non-invasive clinical techniques quantifying repolarization variability: T-wave alternans (TWA) and beat-to-beat variability of repolarization (BVR). We discuss their pathophysiological link with ventricular arrhythmia and the current clinical relevance of these techniques.

Preventing Sudden Cardiac Death in Patients with Ischaemic Cardiomyopathy

Sudden cardiac death (SCD) is an important cause of mortality. In this article, we review the definition, impact and underlying aetiology of SCD. Ventricular tachyarrhythmia accounts for the majority of SCDs and can be caused by various underlying heart diseases, the most frequent being ischaemic cardiomyopathy. The most effective ways to reduce the risk of SCD in ischaemic cardiomyopathy are the optimal prevention of recurrent coronary ischaemia and the use of an implantable cardioverter-defibrillator (ICD) in high-risk patients. We discuss current patient selection for ICD implantation and focus on the need for, and possibilities to improve, SCD risk stratification.

Rationale, objectives, and design of the EUTrigTreat clinical study: a prospective observational study for arrhythmia risk stratification and assessment of interrelationships among repolarization markers and genotype

Aims

The EUTrigTreat clinical study has been designed as a prospective multicentre observational study and aims to (i) risk stratify patients with an implantable cardioverter defibrillator (ICD) for mortality and shock risk using multiple novel and established risk markers, (ii) explore a link between repolarization biomarkers and genetics of ion (Ca²⁺, Na⁺, K⁺) metabolism, (iii) compare the results of invasive and non-invasive electrophysiological (EP) testing, (iv) assess changes of non-invasive risk stratification tests over time, and (v) associate arrythmogenomic risk through 19 candidate genes.

Methods and results

Patients with clinical ICD indication are eligible for the trial. Upon inclusion, patients will undergo non-invasive risk stratification, including beat-to-beat variability of repolarization (BVR), T-wave alternans, T-wave morphology variables, ambient arrhythmias from Holter, heart rate variability, and heart rate turbulence. Non-invasive or invasive programmed electrical stimulation will assess inducibility of ventricular arrhythmias, with the latter including recordings of monophasic action potentials and assessment of restitution properties. Established candidate genes are screened for variants. The primary endpoint is all-cause mortality, while one of the secondary endpoints is ICD shock risk. A mean follow-up of 3.3 years is anticipated. Non-invasive testing will be repeated annually during follow-up. It has been calculated that 700 patients are required to identify risk predictors of the primary endpoint, with a possible increase to 1000 patients based on interim risk analysis.

Conclusion

The EUTrigTreat clinical study aims to overcome current shortcomings in sudden cardiac death risk stratification and to answer several related research questions. The initial patient recruitment is expected to be completed in July 2012, and follow-up is expected to end in September 2014.

Clinicaltrials.gov identifier: NCT01209494.

Implantable cardioverter/defibrillator interventions in primary prevention: do current implantation criteria really predict ICD interventions?

BACKGROUND

Randomized controlled trials have proven the efficacy of implantable cardioverter/defibrillators (ICDs) to prevent sudden cardiac death (SCD) in primary prevention. However,long-term data on the incidence of appropriate and inappropriate interventions in real life and on the predictive value of commonly used clinical variables to guide patient selection are scarce.

METHODS

We retrospectively studied 101 patients who received an ICD for primary prophylaxis of SCD: 63.4% with ischaemic heart disease (IHD) and 36.6% with idiopathic dilated cardiomyopathy (IDCM). The mean follow-up period was 26.2 (+/- 14.8; median 27.8; range 5.6-70.5) months. Age, left ventricular ejection fraction (LVEF), QRS duration, NYHA class and electrophysiological study (EPS) outcome were evaluated as predictors of ICD intervention.

RESULTS

At 2 years the cumulative incidence of appropriate (17.5% in IHD; 28% in IDCM; P= 0.63) and inappropriate (12.8% in IHD, 15.4% in IDCM; P = 0.62) interventions was similar in both groups. Atrial fibrillation was the most common cause of inappropriate interventions in the IHD group, sinus tachycardia in the IDCM group. Advanced age was associated with less inappropriate interventions (HR: 0.96 (95% confidence interval (CI) 0.94-0.98); P < 0.01), and a better LVEF with less appropriate interventions (HR: 0.97 (95% Cl 0.94-0.99); P < 0.01). This amounted in a significant absolute difference in the number of appropriate interventions between the group with a LVEF < 25% and 25-34% after 3 years of follow-up of 42% in IHD (48% vs 6%). A prolonged QRS duration was associated with a slightly elevated risk for appropriate interventions only in the IHD group (HR: 1.01 (95% CI 1.00-1.03); P = 0.04). On the other hand, increased NYHA class was only associated with increased risk for appropriate interventions in the IDCM group (HR: 5.24 (95% CI1.11-24.74); P= 0.04). No significant statistical association was found between a positive EPS and appropriate or inappropriate interventions.

CONCLUSIONS

In primary prevention, during a mean follow-up of 2 years, one in five patients had a possibly live-saving appropriate intervention. However, the incidence of inappropriate interventions was substantial. Predictors for appropriate interventions were: (i) LVEF in the total study group, (ii) NYHA class in the IDCM group and (iii) QRS duration in the IHD group.