Utility of new FDG-PET/CT guidelines for diagnosing cardiac sarcoidosis in patients with implanted cardiac pacemakers for atrioventricular block

Diagnosing cardiac sarcoidosis (CS), especially in isolated cases, is challenging, particularly due to the limitations of endomyocardial biopsy, leading to potential undiagnosed cases in pacemaker-implanted patients. This study aims to provide real world findings to support new guideline for CS using 18F-fluoro-deoxyglucose positron-emission tomography computed tomography (FDG-PET/CT) which give a definite diagnosis of isolated CS (iCS) without histological findings. We examined consecutive patients with cardiac pacemakers for atrioventricular block (AV-b) attending our outpatient pacemaker clinic. The patients underwent periodical follow-up echocardiography and were divided into two groups according to echocardiographic findings: those with suspected CS and those without suspected CS. Patients suspected of having nonischemic cardiomyopathy underwent FDG-PET/CT for CS diagnosis. We investigated the utility of the new guideline for CS using FDG-PET/CT. Among the 272 patients enrolled, 97 patients were implanted with cardiac pacemakers for AV-b. Twenty-two patients were suspected of having CS during a median observation period of 5.4 years after pacemaker implantation. Of these, one did not consent, and nine of 21 cases (43%) were diagnosed with definite CS according to the new guidelines. Five of these nine patients were diagnosed with iCS using FDG-PET/CT. The number of patients diagnosed with definite CS using the new guidelines tended to be approximately 2.3 times that of the conventional criteria (p = 0.074). Three of the nine patients underwent steroid treatment. The composite outcome, comprising all-cause death, heart failure hospitalization, and a substantial reduction in left ventricular ejection fraction, were significantly lower in patients receiving steroid treatment compared to those without steroid treatment (p = 0.048). The utilization of FDG-PET/CT in accordance with the new guidelines facilitates the diagnosis of CS, including iCS, resulting in approximately 2.3 times as many diagnoses of CS compared to the conventional criteria. This guideline has the potential to support the early identification of iCS and may contribute to enhancing patient clinical outcomes.

Ratio of left ventricular outflow tract area to aortic annulus area and complete atrioventricular block after transcatheter aortic valve replacement for aortic stenosis

BACKGROUND

Mechanical compression of cardiac conduction system by transcatheter heart valves leads to complete atrioventricular block (CAVB) after transcatheter aortic valve replacement (TAVR). Bulging of ventricular septum in the left ventricular outflow tract (LVOT) may be associated with greater compression of conduction system, leading to irreversible CAVB.

OBJECTIVE

This study aimed to investigate the association of ventricular septal bulging with TAVR-related CAVB and permanent pacemaker implantation (PPI).

METHODS

Among 294 consecutive patients with severe aortic stenosis who underwent TAVR between July 2017 and February 2023, 271 were included in the analysis. As a quantitative evaluation of bulging of the ventricular septum, the ratio of LVOT area to aortic annulus area (L/A ratio) was measured at the systolic phase of computed tomography images.

RESULTS

TAVR-related CAVB occurred in 64 patients (23.6%). Twenty-eight patients (10.3%) required PPI. The optimal thresholds of L/A ratio for predicting TAVR-related CAVB and PPI were 1.0181 and 0.985, respectively. Patients with less than the cut-off values had higher rate of TAVR-related CAVB and PPI than those above (28.3% vs 13.1%, p = 0.0063; 14.7% vs 4.4%, p = 0.0077, respectively). A multivariate analysis showed that L/A ratio < 1.0181 was an independent predictor of TAVR-related CAVB (odds ratio [OR] 2.65, p = 0.011), in addition to prior right bundle branch block (OR 3.76, p = 0.0005), use of a self-expanding valve (OR 1.99, p = 0.030), and short membranous septum length (OR 0.96, p = 0.037). Only L/A ratio < 0.985 was independently associated with PPI (OR 3.70, p = 0.011).

CONCLUSION

Low L/A ratio is a predictor of TAVR-related CAVB and PPI.

FDG-PET/CT and rest myocardial perfusion imaging to predict high-degree atrioventricular block recovery in cardiac sarcoidosis

BACKGROUNDS

High-degree atrioventricular block (AVB) recovery in CS has been shown to be highly variable despite immunosuppressive treatment, with no reliable tool available to predict odds of reversibility. This study sought to evaluate the potential of combined fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and resting myocardial perfusion imaging (rMPI) to predict reversibility of newly diagnosed high-grade AVB in cardiac sarcoidosis (CS).

METHODS

We performed a single-center, retrospective analysis of patients with CS presenting with high-grade AVB who underwent combined FDG-PET/CT and rMPI. The 2016 JCS and the 2014 HRS diagnostic criteria were used for the diagnosis of CS. Patients with a history of coronary artery disease or prior immunosuppressive treatment were excluded. Patients were divided into AVB recovery and non-recovery subgroups. CS disease staging was based on FDG-PET and rMPI findings: (Stage 0) normal FDG-PET and rMPI (Stage 1) positive FDG-PET and normal rMPI (Stage 2) positive FDG-PET with perfusion deficits on rMPI (Stage 3) normal FDG-PET with perfusion deficits on rMPI.

RESULTS

Twenty-seven patients, including 13 demonstrating AVB recovery, were identified. Eleven out of fourteen (78.6%) patients presenting with stage 1 CS demonstrated AVB recovery. Stage 1 CS was significantly more present in the recovery group compared to the non-recovery group (84.6% vs 21.4%, P = .002). Eleven presented with stage 2 CS, with only 2 (18.2%) recovering AV nodal conduction. Stage 2 CS presented more frequently in the non-recovery group (64.3% vs 15.4%, P = .020).

CONCLUSIONS

Combined FDG-PET and rMPI employed to stage CS disease presenting with high-degree AVB appears to have good performance for predicting likelihood of recovery.

Cardiac Hydatid Cyst: An Uncommon Cause of Complete Atrioventricular Block

Hydatidosis is a zoonosis caused by Echinococcus granulosus, leading to the formation of cysts on involved organs. Cardiac involvement is rare and can cause a wide range of complications secondary to rupture, embolization, or compression. Its diagnosis is challenging, and is generally confirmed through data related to clinical manifestations, environmental exposure, and laboratory and imaging exams. Surgical removal is necessary in most cases, in which an association with antiparasite therapy is recommended. The present article describes a case of a cardiac hydatid cyst associated with a complete atrioventricular block (AVB) in a young adult patient, with the need for a pacemaker implant, an atypical presentation, and scarce reports in the literature.

Acute echocardiographic and hemodynamic response to his-bundle pacing in patients with first-degree atrioventricular block

BACKGROUND

Atrial pacing and right ventricular (RV) pacing are both associated with adverse outcomes among patients with first-degree atrioventricular block (1°AVB). His-bundle pacing (HBP) provides physiological activation of the ventricle and may be able to improve both atrioventricular (AV) and inter-ventricular synchrony in 1°AVB patients. This study evaluates the acute echocardiographic and hemodynamic effects of atrial, atrial-His-bundle sequential (AH), and atrial-ventricular (AV) sequential pacing in 1°AVB patients.

METHODS

Patients with 1°AVB undergoing atrial fibrillation ablation were included. Following left atrial (LA) catheterization, patients underwent atrial, AH- and AV-sequential pacing. LA/left ventricular (LV) pressure and echocardiographic measurements during the pacing protocols were compared.

RESULTS

Thirteen patients with 1°AVB (mean PR 221 ± 26 ms) were included. The PR interval was prolonged with atrial pacing compared to baseline (275 ± 73 ms, p = .005). LV ejection fraction (LVEF) was highest during atrial pacing (62 ± 11%), intermediate with AH-sequential pacing (59 ± 7%), and lowest with AV-sequential pacing (57 ± 12%) though these differences were not statistically significant. No significant differences were found in LA or LV mean pressures or LV dP/dT. LA and LV volumes, isovolumetric times, electromechanical delays, and global longitudinal strains were similar across pacing protocols.

CONCLUSION

Despite pronounced PR prolongation, the acute effects of atrial pacing were not significantly different than AH- or AV-sequential pacing. Normalizing atrioventricular and/or inter-ventricular dyssynchrony did not result in acute improvements in cardiac output or loading conditions.

Congenital complete atrioventricular block from literature to clinical approach - a case series and literature review

AIM

Congenital atrioventricular block (CAVB) is an immunological condition, secondary to the transfer of maternal Ig G antibodies from seropositive mothers. Although the presence of these antibodies is high among pregnant women, the preva-lence of this fetal pathology is low. The aim of this paper is to analyze a series of cases with intrauterine diagnosis of CAVB and to present their follow-up protocol.

MATERIAL AND METHOD

In the period between 2013-2020, five fetuses were diagnosed and followed up in the Pediatric Cardiology Clinic. In each of the cases, assessment of the hemodynamic status was done by calculation of the fetal cardiovascular profile score (CVPS). In the last cases the follow-up protocol was supplemented with longitudinal speckle tracking evaluation of the ventricular function.

RESULTS

In the present series, intrauterine death occurred in one case; in another case resumption of atrioventricular conduction was observed. Epicardial pacemaker implantation was required in three of the patients.

CONCLUSION

Completing the evaluation of ventricular function with the longitudinal speckle tracking method in fetuses and newborn patients with congenital atrioventricular block may play an important role in establish-ing therapeutic behavior.

Outcomes of single‑lead VDD pacemakers in atrioventricular blocks: The OSCAR study

BACKGROUND

VDD pacemakers are regarded as a second choice in patients with atrio-ventricular blocks mainly due to the potential failure of atrial sensing, leading to a loss of atrio-ventricular synchrony. This single-centre study aimed to evaluate the prevalence of loss of atrial sensing and its potential determinants in patients with VDD pacemakers.

METHOD

142 patients with an implanted VDD device underwent long-term follow-up with clinical evaluation, electrocardiogram, device interrogation and echocardiogram.

RESULTS

Over a long follow-up period [median 110 (68-156) months], 17 patients (12%) in sinus rhythm presented loss of atrial sensing. This was most often intermittent, but three patients required a permanent switch to VVI mode. ECG showed higher prevalence of interatrial blocks (50% vs 26.6%, p = 0.057) and longer P wave duration (116 ± 19 vs 105 ± 15 ms, p = 0.019) in patients with loss of atrial sensing. Echocardiography revealed larger left atrial (LA) volumes (p < 0.05) in patients with loss of atrial sensing, and lower LA ejection fraction (0.40 vs 0.47, p = 0.0037) and expansion index (0.63 ± 0.26 vs 0.90 ± 0.31, p = 0.003). P wave duration on ECG proved to be independently associated with loss of atrial sensing on multivariable analysis (OR 1.062, 95% CI 1.015-1.110; p = 0.008). The prevalence of atrial fibrillation and subsequent switch to VVI mode was high (16%).

CONCLUSIONS

In the long-term follow-up, the loss of atrial sensing is present in 12% of patients with implanted VDD pacemakers. ECG and echocardiographic parameters may serve as screening tools for the detection of atrial myopathy which is associated with the loss of atrial sensing.

Treatment of atrial fibrillation with third-degree atrioventricular block by pacing His bundle and left bundle branch: Case report

INTRODUCTION

Substantial advances in cardiac pacing technology have been developed in the past decades. However, efforts to improve pacing technology to achieve physiological electrical activity, such as with cardiac resynchronization therapy, are underway. Permanent His bundle pacing, which directly stimulates the His-Purkinje network and electrically activates both ventricles, simulates physiological electric activity in the heart, and has been considered an ideal pacing strategy to treat arrhythmias. For patients with atrial fibrillation complicated by third-degree atrioventricular block (AVB), permanent His bundle pacing is a better option than conventional right ventricular apical or septal pacing, the latter of which may be associated with risks, such as heart failure. However, His bundle pacing exhibits some shortcomings, including elevated pacing threshold, dislocation, and abnormal sensing.

CASE PRESENTATION

A 69-year-old female patient who had atrial fibrillation (AF) complicated by third-degree AVB and who was treated with permanent His bundle pacing combined with left bundle branch pacing.

DIAGNOSIS

AF complicated by third-degree AVB.

INTERVENTIONS

We used the left bundle branch as a backup pacing site to overcome any shortcomings related to permanent His bundle pacing.

OUTCOMES

The patient recovered well without any events.

CONCLUSION

We selected His bundle pacing as the primary pacing, but also used left bundle branch pacing as a backup approach. If His bundle pacing results in an increased sensing threshold, pacing threshold changes, or dislocations, left bundle branch pacing can compensate for dysfunction of permanent deficiencies in His bundle pacing, preserving physiological pacing.

[An unusual presentation of cardiac involvement during the COVID-19 pandemic]

Severe acute respiratory syndrome coronavirus 2 may affect the cardiovascular system and cause acute cardiac injury. Other authors described cases of myocarditis with reduced systolic function and/or a life-threatening presentation. We describe the clinical course of an unusual presentation with isolated reversible high degree atrioventricular block in a patient with COVID-19. In this case, a "wait and see approach" avoided an unnecessary permanent pacemaker implantation.

Periventricular nodular heterotopia

BACKGROUND

Periventricular nodular heterotopia (PNH) is an embryonal neuronal migration disturbance of the brain. The condition is rare and genetically heterogeneous, often caused by mutations in the FLNA gene. The most common symptoms are epileptic seizures. PNH is often associated with other conditions such as cardiovascular abnormalities.

CASE PRESENTATION

A young man was admitted to hospital after a first episode of loss of consciousness. The patient was in normal general condition upon admission, and the clinical examination revealed no abnormalities. However, cerebral imaging performed upon admittance showed PNH, while an extended cardiac examination revealed atrioventricular block with the indication for a pacemaker. After pacemaker implantation and introduction of antiepileptic drug therapy, the patient has been free of symptoms.

INTERPRETATION

PNH is a condition that needs multidisciplinary assessments.

Cisd2 is essential to delaying cardiac aging and to maintaining heart functions

CDGSH iron-sulfur domain-containing protein 2 (Cisd2) is pivotal to mitochondrial integrity and intracellular Ca2+ homeostasis. In the heart of Cisd2 knockout mice, Cisd2 deficiency causes intercalated disc defects and leads to degeneration of the mitochondria and sarcomeres, thereby impairing its electromechanical functioning. Furthermore, Cisd2 deficiency disrupts Ca2+ homeostasis via dysregulation of sarco/endoplasmic reticulum Ca2+-ATPase (Serca2a) activity, resulting in an increased level of basal cytosolic Ca2+ and mitochondrial Ca2+ overload in cardiomyocytes. Most strikingly, in Cisd2 transgenic mice, a persistently high level of Cisd2 is sufficient to delay cardiac aging and attenuate age-related structural defects and functional decline. In addition, it results in a younger cardiac transcriptome pattern during old age. Our findings indicate that Cisd2 plays an essential role in cardiac aging and in the heart's electromechanical functioning. They highlight Cisd2 as a novel drug target when developing therapies to delay cardiac aging and ameliorate age-related cardiac dysfunction.

Fortuitous Identification of Fluctuating AV Block: A Case Report

BACKGROUND

Vagally mediated atrioventricular block (AVB) may occur as a result of increased parasympathetic tone. This particular AVB is infrequently described in the literature, but its prevalence may be underestimated, as it may occur without recognition.

CASE REPORT

We present a case of vagally mediated AVB that was identified by serial electrocardiography of a patient who presented to the emergency department with vomiting. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Vagally mediated AVB must be differentiated from paroxysmal, bradycardia-dependent AVB, which may progress to persistent AVB and require pacemaker placement. In an asymptomatic patient with vagally mediated AVB, pacemaker placement is contraindicated. However, if symptoms are clearly attributable to vagally mediated AVB, pacemaker placement may be reasonable.

Incidence of atrioventricular block with vasodilator stress SPECT: A meta-analysis

BACKGROUND

Adenosine or regadenoson are often used with pharmacologic stress testing. Adenosine may trigger atrioventricular block (AVB). Despite its higher selectivity, regadenoson has also been associated with AVB. We studied the incidence of de novo AVB with these agents.

METHODS

A comprehensive search of SCOPUS was performed from inception to March 2016. Studies of at least 10 patients, using adenosine and/or regadenoson with SPECT-MPI, reporting rates of AVB were selected for further review.

RESULTS

Thirty four studies were pooled including 22,957 patients. Adenosine was used in 21 studies and regadenoson in 15. Both were administered in two studies. The estimated incidence of overall and high-grade AVB was 3.81% (95% CI 1.99%-6.19%) and 1.93% (95% CI 0.77%-3.59%), respectively. The incidence of AVB (8.58%; 95% CI 5.55%-12.21% vs 0.30%; 95% CI 0.04%-0.82%, respectively, P < .001) and high-grade AVB (5.21%; 95% CI 2.81%-8.30% vs 0.05%; 95% CI < .001%-0.19% respectively, P < .001) were higher with adenosine compared to regadenoson.

CONCLUSION

AVB is seen in about 4% of patients undergoing vasodilator stress test. Both overall and high-grade AVB are more frequent with adenosine compared to regadenoson.

Diagnostic value of cardiac magnetic resonance and fluorodeoxyglucose-positron emission tomography for cardiac sarcoidosis with previous myocardial infarction: A case report

RATIONALE

Diagnostic difficulty due to overlapped clinical findings exists in cardiac sarcoidosis (CS) patients who also have coronary artery disease. Since cardiac magnetic resonance (CMR) and fluorodeoxyglucose-positron emission tomography (FDG-PET) evaluate different pathological processes, that is, fibrosis and inflammation respectively, the combination may be useful in such a case.

PATIENT CONCERNS

A 77-year-old man was admitted due to heart failure and advanced atrioventricular block who was previously diagnosed with cutaneous sarcoidosis and old myocardial infarction (MI) with angiographical evidence.

DIAGNOSIS

He was finally diagnosed with CS using CMR and FDG-PET by specifying the myocardial lesion of sarcoidosis.

INTERVENTIONS

He was treated with corticosteroids based on the diagnosis.

OUTCOMES

The focal high uptake on FDG-PET was improved and he had a better clinical course without further cardiac events.

LESSONS

Our case suggests that CMR and FDG-PET are complimentary, and the combination is useful for diagnosis of CS, particularly in cases that have previous MI.

Association of cardiac implantable electronic devices with survival in bifascicular block and prolonged PR interval on electrocardiogram

PURPOSE

Bifascicular block and prolonged PR interval on the electrocardiogram (ECG) have been associated with complete heart block and sudden cardiac death. We sought to determine if cardiac implantable electronic devices (CIED) improve survival in these patients.

METHODS

We assessed survival in relation to CIED status among 636 consecutive patients with bifascicular block and prolonged PR interval on the ECG. In survival analyses, CIED was considered as a time-varying covariate.

RESULTS

Average age was 76 ± 9 years, and 99% of the patients were men. A total of 167 (26%) underwent CIED (127 pacemaker only) implantation at baseline (n = 23) or during follow-up (n = 144). During 5.4 ± 3.8 years of follow-up, 83 (13%) patients developed complete or high-degree atrioventricular block and 375 (59%) died. Patients with a CIED had a longer survival compared to those without a CIED in the traditional, static analysis (log-rank p < 0.0001) but not when CIED was considered as a time-varying covariate (log-rank p = 0.76). In the multivariable model, patients with a CIED had a 34% lower risk of death (hazard ratio 0.66, 95% confidence interval 0.52-0.83; p = 0.001) than those without CIED in the traditional analysis but not in the time-varying covariate analysis (hazard ratio 1.05, 95% confidence interval 0.79-1.38; p = 0.76). Results did not change in the subgroup with a pacemaker only.

CONCLUSIONS

Bifascicular block and prolonged PR interval on ECG are associated with a high incidence of complete atrioventricular block and mortality. However, CIED implantation does not have a significant influence on survival when time-varying nature of CIED implantation is considered.

Exercise-induced Atrioventricular Block with Coronary Artery Stenosis that Appeared Five Years after Bypass Surgery

A 68-year-old man with a history of coronary artery bypass surgery was referred to our hospital because of pre-syncope on effort. During a treadmill exercise electrocardiogram test, the patient developed advanced atrioventricular block associated with dizziness. Coronary angiography revealed significant stenosis of the right coronary artery, which had not existed at the time of the bypass surgery. We implanted drug-eluting stents in the stenotic lesion, and an exercise test showed resolution of the atrioventricular block. Exercise-induced atrioventricular block is rare, and it is necessary to distinguish it from ischemic heart disease, especially in patients with a history of coronary artery disease.

Detecting Cardiac Sarcoidosis with a Right Atrial Mass Using Transthoracic Echocardiography

An asymptomatic 40-year-old woman with a first-degree atrioventricular block presented a right atrial mass in transthoracic echocardiograms. Transesophageal echocardiograms showed abnormally thickened tissue on the interatrial septum, which extended around the aortic annulus. Multimodality examinations demonstrated lesions in the heart, lungs, liver, and spleen, suggesting sarcoidosis. She was diagnosed with cardiac sarcoidosis after we detected granulomas in a lung specimen. A right atrial mass shrunk following steroid therapy. We should therefore consider the possibility of cardiac sarcoidosis when we see wall thickening and a mass echo in the atrium. These signs may point to an early-phase lesion of cardiac sarcoidosis.

TEMPORARY PACE MAKERS IMPLANTATION: DO WE NEED FLUOROSCOPY?

BACKGROUND

Temporary pace maker (TPM implantation is done mostly in emergency with assistance of fluoroscopy. Fluoroscopy has various constrains which may delay the procedure at different occasion. We are going to share our experience in TPM implantation without fluoroscopy from internal jugular vein.

METHODS

The case series study was conducted in Hayatabad Medical complex Peshawar from January 2011 to November 2011. Internal jugular vein was cannulated with 6 French sheaths in the supra-clavicular region with modified Seldinger technique. TPM wire connected to the TPM device and advanced in the sheath to the right ventricle. Position was confirmed from captured beat on monitor. There was no need of repositioning and lead remains stable.

RESULTS

Total 122 TPM leads were implanted in the study period. All patients were implanted from internal jugular vein. There were 71 male and 51 female patients. Among these patients 55 were in hemodynamically unstable state. The average time of implantation was less than 10 minutes. There was failure in one case. So the overall success rate was 99.180%.

CONCLUSION

TPM implantation from the internal jugular vein even without fluoroscopy is safe, less time consuming and convenient.

Prevalence of E/A wave fusion and A wave truncation in DDD pacemaker patients with complete AV block under nominal AV intervals

Aims

Optimization of the AV-interval (AVI) in DDD pacemakers improves cardiac hemodynamics and reduces pacemaker syndromes. Manual optimization is typically not performed in clinical routine. In the present study we analyze the prevalence of E/A wave fusion and A wave truncation under resting conditions in 160 patients with complete AV block (AVB) under the pre-programmed AVI. We manually optimized sub-optimal AVI.

Methods

We analyzed 160 pacemaker patients with complete AVB, both in sinus rhythm (AV-sense; n = 129) and under atrial pacing (AV-pace; n = 31). Using Doppler analyses of the transmitral inflow we classified the nominal AVI as: a) normal, b) too long (E/A wave fusion) or c) too short (A wave truncation). In patients with a sub-optimal AVI, we performed manual optimization according to the recommendations of the American Society of Echocardiography.

Results

All AVB patients with atrial pacing exhibited a normal transmitral inflow under the nominal AV-pace intervals (100%). In contrast, 25 AVB patients in sinus rhythm showed E/A wave fusion under the pre-programmed AV-sense intervals (19.4%; 95% confidence interval (CI): 12.6–26.2%). A wave truncations were not observed in any patient. All patients with a complete E/A wave fusion achieved a normal transmitral inflow after AV-sense interval reduction (mean optimized AVI: 79.4 ± 13.6 ms).

Conclusions

Given the rate of 19.4% (CI 12.6–26.2%) of patients with a too long nominal AV-sense interval, automatic algorithms may prove useful in improving cardiac hemodynamics, especially in the subgroup of atrially triggered pacemaker patients with AV node diseases.

Diastolic Function in Paced Children with Cardiac Defects: Septum vs Apex

In children with structural congenital heart disease (CHD), the effects of chronic ventricular pacing on diastolic function are not well known. On the other hand, the beneficial effect of septal pacing over apical pacing is still controversial.

The aim of this study was to evaluate the influence of different right ventricular (RV) pacing site on left ventricular (LV) diastolic function in children with cardiac defects.

Twenty-nine pediatric patients with complete atrioventricular block (CAVB) and CHD undergoing permanent pacing were prospectively studied. Pacing sites were RV apex (n = 16) and RV septum (n = 13). Echocardiographic assessment was performed before pacemaker implantation and after it, during a mean follow‑up of 4.9 years.

Compared to RV septum, transmitral E-wave was significantly affected in RV apical pacing (95.38 ± 9.19 vs 83 ± 18.75, p = 0.038). Likewise, parameters at the lateral annular tissue Doppler imaging (TDI) were significantly affected in children paced at the RV apex. The E´ wave correlated inversely with TDI lateral myocardial performance index (Tei index) (R²= 0.9849, p ≤ 0.001). RV apex pacing (Odds ratio, 0.648; confidence interval, 0.067-0.652; p = 0.003) and TDI lateral Tei index (Odds ratio, 31.21; confidence interval, 54.6-177.4; p = 0.025) predicted significantly decreased LV diastolic function.

Of the two sites studied, RV septum prevents pacing-induced reduction of LV diastolic function.

The acute and chronic effects of different right ventricular site pacing on left ventricular mechanical synchrony as assessed by phase analysis of SPECT myocardial perfusion imaging

BACKGROUND

This study aimed to assess acute and chronic effects of right ventricular mid-septum (RVS) versus right ventricular apex (RVA) pacing on left ventricular (LV) mechanical dyssynchrony using phase analysis of gated single photon emission computed tomography myocardial perfusion imaging (MPI).

METHODS

Thirty-nine patients with complete atrioventricular (AV) block, who were indicated for permanent pacing, were recruited and randomized to receive RVA (n = 20) or RVS (n = 19) pacing. All patients underwent MPI at 1 week and 6 months after pacemaker implantation. LV dyssynchrony and cardiac function were assessed by MPI and compared between the two groups.

RESULTS

There were no significant differences in baseline characteristics between the RVS and RVA groups. The paced QRS duration was significantly longer in the RVA group than in the RVS group. LV dyssynchrony parameters were not significantly different between the groups at the 1-week follow-up, but they were significantly smaller in the RVS group than in the RVA group at the 6-month follow-up. LV dyssynchrony parameters significantly decreased in the RVS group from the 1-week follow-up to the 6-month follow-up, but were unchanged in the RVA group. No differences in LV function parameters were observed between the groups at the 1-week and 6-month follow-ups.

CONCLUSIONS

RVS pacing produces better electrical and mechanical synchrony than RVA pacing for patients with complete AV block.

Doppler echocardiographic isovolumetric time intervals in diagnosis of fetal blocked atrial bigeminy and 2:1 atrioventricular block

OBJECTIVE

To distinguish between blocked atrial bigeminy (BB) and incomplete atrioventricular block with 2:1 conduction (2:1 AVB) can be very difficult, especially in the mid-term fetus. Making a correct diagnosis has important clinical implications, as their prognosis and management differ markedly. Our objective was to investigate whether analysis of isovolumetric time intervals could improve Doppler echocardiography in differentiating these conditions.

METHODS

Sixteen fetuses with sustained BB or isolated 2:1 AVB, diagnosed at our tertiary center from 2002 to 2012, were reviewed retrospectively. Doppler recordings of left ventricular in- and outflow, including mitral and aortic valve movements, were used to measure isovolumetric contraction (ICT) and relaxation (IRT) time intervals. ICT reference values obtained from 104 normal pregnancies were used for comparison.

RESULTS

Ten fetuses had BB and six 2:1 AVB. Five of the AVB cases were anti-Ro antibody positive and one had long QT syndrome (LQTS). ICT was systematically shorter in BB than in antibody-mediated 2:1 AVB. Nine of 10 cases with BB had an ICT below -2 SD and the five with antibody-mediated 2:1 AVB had values at or above +2 SD. All 15 fetuses with either BB or antibody-mediated AVB had an IRT of < 70 ms, as opposed to a markedly prolonged IRT (105 ms) in the LQTS case.

CONCLUSION

Measurement of ICT can improve the differential diagnosis between BB and antibody-mediated 2:1 AVB. Fetuses with BB or antibody-mediated AVB are unlikely to have IRT measurements exceeding 70 ms and, when this is observed, LQTS should be considered a more likely diagnosis.

Real-time three-dimensional echocardiographic determination of right ventricular outflow tract high septal pacing sites

OBJECTIVE

To investigate the feasibility of determination of right ventricular outflow tract (RVOT) high septal pacing site visualized by real-time three-dimensional echocardiography (RT3DE).

METHODS

The forty subjects with RVOT pacing were analysed. RT3DE determination of RVOT high septal pacing sites was compared with chest X-ray (CXR).

RESULTS

RVOT septal pacing sites could be obtained in all patients by RT3DE.When pacing sites were categorized as septal or non-septal, there were good agreements between echocardiography and CXR (kappa = 0.745). However, when RVOT pacing sites were categorized as high septal or non-high septal in identifying the exact anatomic location of pacing sites, there was only mild agreement between echocardiography and CXR (kappa = 0.275). Moreover, when RT3DE was used as the gold standard in identifying the exact anatomic location of RVOT, pacing at the RVOT high septal could only be achieved in 37.5% (n= 15) of patients using RT3DE, but in 65% (n= 26) using CXR, because the RVOT septal pacing lead tip found at high septal by CXR is actually found at low septal or free wall by RT3DE.

CONCLUSION

It is limited to accurately locate RVOT high septal pacing site only by CXR, RT3DE allows to determinate the RVOT high septal pacing sites helpfully.

Mechanisms in fetal bradyarrhythmia: 65 cases in a single center analyzed by Doppler flow echocardiographic techniques

OBJECTIVE

Fetal bradyarrhythmias have various underlying mechanisms. As blocked atrial bigeminy (BB) generally resolves spontaneously, but incomplete atrioventricular block (AVB) might respond to steroid treatment, correct diagnosis is of major importance. Our objectives were to assess the underlying mechanisms in fetal bradyarrhythmia and the accuracy of Doppler techniques in differentiating between them.

METHODS

Seventy-eight patients referred to our tertiary center between 1990 and 2007 for evaluation of fetal bradycardia were analyzed retrospectively. Besides Doppler recordings from the mitral valve/aorta, superior vena cava/aorta and pulmonary vein/peripheral pulmonary artery, we used recordings from the pulmonary trunk and ductus venosus. We calculated the ratio of the time interval between conducted and consecutive blocked atrial contractions divided by the interval between two conducted atrial beats (a(cb) /a(cc) ), to analyze more meticulously the atrial rhythm in BB and second-degree AVB.

RESULTS

Fetal bradycardia ( ≤ 110 bpm) was confirmed in 65 of the 78 referred cases. Twenty-five had AVB (of which 20 were complete AVB), 29 had BB (of which 23 were intermittent) and 11 had sinus bradycardia. The bradyarrhythmic mechanism was identified correctly in all but one fetus with an atrial ectopic rhythm. Heart rates < 65 bpm were not seen in fetuses diagnosed with BB and rates < 60 bpm were seen only in cases with complete AVB, but heart rate did not distinguish between BB and AVB in the 60-75 bpm range. The a(cb) /a(cc) ratio clearly differentiated between fetsues with BB and those with second-degree AVB, including during midgestation, when it was difficult to distinguish these fetuses.

CONCLUSIONS

Using Doppler flow recordings, the mechanism causing fetal bradycardia can be clarified. In most cases this can be accomplished by visual validation only, and meticulous measurements are needed mainly to distinguish midterm fetuses with BB from those with second-degree AVB.

Diagnostic precision of Doppler flow echocardiography in fetuses at risk for atrioventricular block

OBJECTIVE

To investigate the diagnostic precision of three Doppler methods in their ability to predict postnatal first-degree atrioventricular (AV) block.

METHODS

This was a prospective, observational study carried out from December 1999 to March 2008, including 95 fetuses of anti-SSA/Ro positive mothers undergoing weekly fetal echocardiograms at 18-24 weeks' gestation. Doppler-derived AV time intervals for left ventricular inflow (MV), inflow and outflow (MV-Ao) and superior vena cava a-wave to aortic flow (SVC-Ao) were compared with the PR interval on postnatal electrocardiography. Reference values for MV intervals were established from 102 healthy fetuses, with previously published reference ranges used for the two other methods. Bayesian and receiver-operating characteristics (ROC) curve analyses were performed.

RESULTS

The prevalence of first-degree AV block at birth was 13.8%. Using a cut-off at the upper 95% confidence limit, MV-Ao and SVC-Ao time intervals had a sensitivity of 91.7%, and negative predictive value and negative likelihood ratio of 98.4% and 0.10, respectively. The corresponding positive predictive value/positive likelihood ratio for MV-Ao and SVC-Ao were 42.3%/4.5 and 47.8%/5.7, respectively. The areas under the ROC curve (AUC) for MV-Ao and SVC-Ao were 0.87 and 0.89, respectively (both P < 0.001), with generated cut-offs for abnormal AV time intervals at 134-138 and 132-138 ms. MV time intervals using a cut-off at the upper 95% confidence limit had a sensitivity of just 50% and an AUC of 0.74 (P < 0.01).

CONCLUSION

The MV-Ao and SVC-Ao Doppler methods make it possible to identify nearly all fetuses with first-degree AV block at birth and to exclude conduction disturbances in the case of a normal AV time measurement but at the cost of a positive predictive value of 50%.

Ultrasonographic diagnosis of delayed atrioventricular conduction during fetal life: a reliability study

OBJECTIVE

The objective of the study was to evaluate the reliability of the 2 most commonly used ultrasonographic approaches for monitoring fetal atrioventricular conduction time (AVCT): (1) superior vena cava/ascending aorta (SVC/AA), and (2) left ventricular inflow/outflow tract (LVI/O) Doppler recordings.

STUDY DESIGN

Echographic studies from fetuses followed up for first-degree atrioventricular block (AVB-1) between 1998 and 2008 were reviewed. The ability to identify atrial contractions in the same fetuses by the SVC/AA and LVI/O approaches was analyzed.

RESULTS

Sixty-six studies of 13 fetuses with AVB-1 were available. Atrial contractions were visible in all SVC/AA studies. With the LVI/O approach, atrial contractions could not be identified in 26 studies (39%). AVCT delay was significantly greater in the nonidentifiable compared with the identifiable atrial contraction group (P < .001). Differences in heart rate and gestational age were not significant.

CONCLUSION

The LVI/O is unsuitable for prenatal screening of conduction system anomalies.

Clinical and angiographic findings of complete atrioventricular block in acute inferior myocardial infarction

INTRODUCTION

The angiographic findings and prognosis of patients with complete atrioventricular block (AVB) complicating acute inferior myocardial infarction (MI) remain unclear.

MATERIALS AND METHODS

The clinical and angiographic findings of 70 consecutive patients with complete AVB were compared with those of 319 patients with inferior MI without AVB (control group) admitted within the same study period.

RESULTS

Patients with complete AVB were older (68 +/- 12 vs 63 +/- 13 years; P = 0.004) and clustered with clinical features indicative of larger infarct size, such as right ventricular infarction, cardiogenic shock, or low left ventricular ejection fraction (LVEF). The onset of the complete AVB was observed within 24 hours in 62 (88.6%), preceded by second-degree AVB in 26 (37.1%) and the escape QRS complex was wide in 8 (11.4%) patients. In patients with complete AVB, a dominant right coronary artery occlusion was found in >95% of cases and in-hospital mortality was increased (27.1% vs 10.7%; P = 0.000), especially in those with widen QRS escape rhythm (75.0%). Reperfusion therapy had a positive impact on the natural course of complete AVB.

CONCLUSIONS

Complete AVB in acute inferior MI was associated with advanced age and larger infarct size. Complete AVB was virtually always caused by dominant right coronary artery occlusion. The in-hospital mortality was significantly higher, but improved by reperfusion therapy. No permanent pacemaker is performed at a mean follow-up of 47 months.

Sinoatrial node artery arising from posterolateral branch of right coronary artery: definition by screening consecutive 1500 coronary angiographies

OBJECTIVE

Sinoatrial node (SAN) artery originates from proximal segment of right coronary artery (RCA) or from left circumflex artery. Sinoatrial node artery artery originating from posterolateral (PL) branch of RCA is very rare. Only several cases have been reported. The study was performed to seek the frequency of this variation, evaluate clinical relevance, and describe electrocardiographic, angiographic characteristics of patients.

METHODS

Consecutive 1500 coronary angiography were screened to detect specifically SAN artery originating from PL branch of RCA. Patients with this variation were followed-up for one year regarding the arrhythmic events.

RESULTS

The origin of SAN artery was proximal RCA in 1280 (85%), circumflex artery in 208 (14%), and PL branch of RCA in 12 (0.8%) patients (8 male, 4 female, mean age 64+/- 9 years). There was no history of arrhythmia in all patients. One patient presented with atrioventricular block. Indications of angiography were stable angina in 5, unstable angina in 5, and acute myocardial infarction in 2 patients. The patient with inferior myocardial infarction due to RCA total occlusion did not develop bradycardia or conduction defect. In four patients (33%) there was another artery originating from proximal RCA, ending at same territory with the variant artery suggesting dual blood supply. During one-year follow-up none of the patients experienced arrhythmic event.

CONCLUSIONS

Sinoatrial node artery originating from distal RCA is very rare. This variation, even in patients with severe RCA disease is not associated with severe arrhythmia. Dual blood supply may be a protective factor in this subgroup of patients from arrhythmic events. To be aware of the origin and course of variant SAN artery may provide safe approach to interventional cardiologist and cardiac surgeon during percutaneous and surgical coronary and atrial interventions.

FDG-PET and MIBI-Tc SPECT as follow-up tools in a patient with cardiac sarcoidosis requiring a pacemaker

A 63-year-old man presented with recent-onset symptoms secondary to third-degree atrio-ventricular block, for which a dual-chamber pacemaker was inserted. Additional investigations resulted in the diagnosis of cardiac sarcoidosis. FDG-PET and MIBI-technetium SPECT were used as follow-up tools for monitoring active granulomatous myocardial infiltration.

Myocardial scintigraphy after pacemaker implantation for congenital complete atrioventricular block

Patients with isolated congenital complete atrioventricular block (CCAVB) occasionally develop dilated cardiomyopathy (DCM), despite early pacemaker implantation. However, the etiology of the DCM and its relationship to permanent ventricular pacing are not fully understood. Twenty-five patients with CCAVB underwent (99m) technetium (Tc) myocardial perfusion scintigraphy. Five patients were studied before and after pacing, providing a total of 30 image sets, which were divided into three groups; group 1: CCAVB before pacemaker implantation (PMI) (n = 11); group 2: CCAVB after PMI who did not subsequently develop DCM (n = 13); group 3: CCAVB after PMI who subsequently developed DCM (n = 6). Perfusion defects on single-photon-emission computed tomography (SPECT) were identified in group 1, 0 of 11 patients; group 2, 85% of patients; and group 3, 100% of patients. In groups 2 and 3, in patients with right ventricular pacing, the perfusion defects were mainly in the septum or between the apex and septum. On 20 segments' polar maps, the distribution of %uptake showed a similar pattern in groups 2 and 3, the degree of decreased %uptake and the number of segments with decreased %uptake being more severe in group 3. "Artificial" left bundle branch block (LBBB) pattern myocardial contraction induced by right ventricular pacing decreased myocardial perfusion around the apex and septum. Some patients with CCAVB will develop left ventricular dysfunction caused by artificial LBBB-induced interventricular asynchrony.

Pacemaker-mediated tachycardia induced by left ventriculography during diagnostic catheterisation: a rare event

Pacemaker-mediated tachycardia (PMT) is an arrhythmia seen in patients implanted with dual-chamber pacemakers. It occurs when ventricular contraction is followed by retrograde conduction to the atrium, which is sensed by the pacemaker, leading to ventricular triggering. A vicious re-entry cycle is set up, leading to incessant tachycardia unless appropriately terminated. A common precipitant is a premature ventricular contraction (PVC). Although PVCs are frequently generated during ventriculography, PMT is an extremely rare event during cardiac catheterisation despite the fact that a large number of patients with implanted pacemakers do undergo the procedure. We report on a case and hope to highlight the possibility of PMT occurring during catheterisation, as well on therapeutic options.

Atrioventicular block in familial amyloidosis; revisiting an old debate

Familial amyloidosis with polyneuropathy (FAP) is the rarest of the cardiac amyloidoses, with less than 200 cases diagnosed each year. In this disease, cardiac involvement is characterized by extracellular amyloid infiltration throughout the heart, usually resulting in sinoatrial nodal dysfunction, cardiomyopathy, and congestive heart failure. While cardiac conduction disturbances are a common feature of FAP, the mechanism of these disturbances seems to be a point of contention among researchers. We present a case of a 78-year-old man with a history of FAP admitted with the diagnosis of atrial fibrillation/flutter. After failing to convert to normal sinus rhythm despite medical therapy, an electrical cardioversion was performed. Following the procedure, the patient converted to symptomatic Mobitz type two second-degree atrioventricular block and required dual chamber pacemaker placement. Our case emphasizes the potential consequences of cardioversion in this progressive condition and the need for further studies on the pathophysiology of cardiac involvement in FAP.

Safety of and tolerance to adenosine infusion for myocardial perfusion single-photon emission computed tomography in a Japanese population

BACKGROUND

Adenosine has been available for use in myocardial perfusion single-photon emission computed tomography (SPECT) in Japan since 2005. The purpose of this study was to evaluate the safety of and tolerance to thallium-201 myocardial perfusion SPECT with intravenous adenosine infusion in Japanese patients with suspected coronary artery disease.

METHODS AND RESULTS

Two hundred and six consecutive patients who underwent an adenosine infusion (120 mug . kg(-1) . min(-1)) SPECT at Sumitomo Besshi Hospital (Niihama, Japan) were investigated. The effects of adenosine infusion were monitored for each patient. A coronary angiography was performed in 81 patients. Adenosine infusion significantly decreased blood pressure and increased heart rate. Adverse reactions were observed in 161 patients (78.2%). Most reactions were transient, disappearing soon after the termination of adenosine infusion. No serious adverse reactions, such as acute myocardial infarction or death, occurred. Adenosine infusion was terminated in 3 patients (1.5%) because of near syncope or sustained 2:1 atrioventricular block. Electrocardiographic changes occurred in 15 patients (7.3%). Self-assessed scoring after SPECT showed that the patients were very tolerant (74.6% of 177 patients) of adenosine infusion myocardial SPECT. The sensitivity and specificity were 75.0% and 69.7%, respectively.

CONCLUSIONS

Adenosine infusion myocardial SPECT is safe and well tolerated in the Japanese population, despite the frequent occurrence of minor adverse reactions.