Long-term follow-up of patients with obstructive hypertrophic cardiomyopathy treated with dual-chamber pacing

Safety and efficacy of alcohol septal ablation in adolescents and young adults with hypertrophic obstructive cardiomyopathy

INTRODUCTION

Data regarding alcohol septal ablation (ASA) in young patients with hypertrophic obstructive cardiomyopathy (HOCM) are scarce. The purpose of our study is to evaluate the safety and efficacy of ASA in patients ≤ 25 years.

METHODS AND RESULTS

All ASAs between 2002 and 2020 at our institution were assigned to a group of patients 14-25 years of age (group 1) and a reference group > 25 years (group 2). 1,264 procedures were analysed in group 2 (58.6 ± 13.5 years) and 41 procedures in group 1 (20.9 ± 3.3 years). The baseline interventricular septal diameter (IVSD) was higher in group 1 (26.0 ± 6.5 mm vs. 21.3 ± 4.4 mm; p < 0.0001). There was no difference in baseline left ventricular outflow tract gradient (LVOTG) (group 1: 54.4 ± 24.4 mmHg; group 2: 52.4 ± 36.6 mmHg; p = n.s.). A previous cardiac device was more often observed in group 1 (31.7% vs. 9.0%; p < 0.0001). Symptoms were improved after 6 months (group 1: mean NYHA class 2.5 at baseline and 1.3 at FU; p < 0.0001; group 2: mean NYHA class 2.7 at baseline and 1.4 at FU; p <0 .0001). IVSD (group 1: 20.3 ± 8.2 mm; group 2: 16.8 ± 5.7 mm; p < 0.0001 for each group compared to baseline) and LVOTG improved during FU (group 1: 25.5 ± 20.0 mmHg; group 2: 22.1 ± 21.7 mmHg; p < 0.0001 for each group). Intrahospital mortality was 0.0% in patients 14-25 years and 0.9% in the reference group. Persistent AV-block was observed in 12.2% of the group 1 and 15.9% of the group 2 patients (p = n.s.).

CONCLUSION

ASA is safe and effective in HOCM patients 14-25 years of age in experienced centres.

Alcohol-induced right bundle branch block is associated with a benign outcome in HOCM after alcohol septum ablation (ASA)

INTRODUCTION

Alcohol septum ablation (ASA) is a treatment option for hypertrophic obstructive cardiomyopathy (HOCM). We examined the impact of ASA-induced bundle branch block (BBB) on clinical and hemodynamic features.

METHODS AND RESULTS

We retrospectively analysed 98 HOCM patients with regard to ASA-induced BBB. Clinical examination was performed at baseline, early after ASA and at chronic follow-up (FU). ASA reduced left ventricular outflow tract gradient (LVOTG) during chronic FU (69.2 ± 41.6 pre vs. 31.8 ± 30.3 mmHg post ASA; p < 0.05) and interventricular septal diameter (21.7 ± 3.4 pre vs. 18.7 ± 5.0 mm post ASA; p < 0.05). ASA-induced early right BBB (RBBB) until discharge was observed in 44.9% and chronic RBBB at FU in 32.7%. Left BBB (LBBB) occurred in 13.3% early after ASA and in only 4.1% at chronic FU. Chronic RBBB was associated with more pronounced exercise-induced LVOTG reduction (102.1 ± 55.2 with vs. 73.6 ± 60.0 mmHg without; p < 0.05). 6-min-walk-test (6-MWT) and NYHA class were not affected by RBBB. LBBB had no influence on LVOTG, 6-MWT and symptoms. More ethanol was injected in patients with early RBBB (1.1 ± 0.4 vs. 0.8 ± 0.3 ml without; p < 0.05), who also showed higher mean CK release (827 ± 341 vs. 583 ± 279 U/l without; p < 0.05). Pacemaker implantation during FU was necessary in 11.5% of patients with early RBBB, 3.1% with chronic RBBB, 7.7% with early LBBB and 0% with chronic LBBB (p = n.s. for BBB vs. no BBB).

CONCLUSION

ASA-induced RBBB is associated with a higher volume of infused ethanol and higher maximum CK release. RBBB does not adversely affect the clinical outcome or need for pacemaker implantation but was associated with higher exercise-induced LVOTG reduction during chronic FU.

Right ventricular pacing for hypertrophic obstructive cardiomyopathy: meta-analysis and meta-regression of clinical trials

Aims

Right ventricular pacing for left ventricular outflow tract gradient reduction in hypertrophic obstructive cardiomyopathy remains controversial. We undertook a meta-analysis for echocardiographic and functional outcomes.

Methods and results

Thirty-four studies comprising 1135 patients met eligibility criteria. In the four blinded randomized controlled trials (RCTs), pacing reduced gradient by 35% [95% confidence interval (CI) 23.2–46.9, P < 0.0001], but there was only a trend towards improved New York Heart Association (NYHA) class [odds ratio (OR) 1.82, CI 0.96–3.44; P = 0.066]. The unblinded observational studies reported a 54.3% (CI 44.1–64.6, P < 0.0001) reduction in gradient, which was a 18.6% greater reduction than the RCTs (P = 0.0351 for difference between study designs). Observational studies reported an effect on unblinded NYHA class at an OR of 8.39 (CI 4.39–16.04, P < 0.0001), 450% larger than the OR in RCTs (P = 0.0042 for difference between study designs). Across all studies, the gradient progressively decreased at longer follow durations, by 5.2% per month (CI 2.5–7.9, P = 0.0001).

Conclusion

Right ventricular pacing reduces gradient in blinded RCTs. There is a non-significant trend to reduction in NYHA class. The bias in assessment of NYHA class in observational studies appears to be more than twice as large as any genuine treatment effect.

Sequential Atrioventricular Pacing in Patients With Hypertrophic Cardiomyopathy: An 18-year Experience

INTRODUCTION AND OBJECTIVES

Controversy persists regarding the role of sequential atrioventricular pacing in patients with obstructive hypertrophic cardiomyopathy and disabling symptoms. The aim of this study was to evaluate the effect of pacing on symptoms, dynamic gradient, and left ventricular function in patients with hypertrophic cardiomyopathy.

METHODS

From 1991 to 2009, dual-chamber pacemakers were implanted in 82 patients with obstructive hypertrophic cardiomyopathy and disabling symptoms despite optimal medical therapy. Sequential pacing was performed with a short atrioventricular delay. Clinical and echocardiographic parameters were measured before and immediately after implantation and after a long follow-up (median, 8.5 years [range, 1-18 years]).

RESULTS

The New York Heart Association functional class was immediately reduced after pacemaker implantation in 95% of patients (P < .0001), and this improvement was maintained until the final follow-up in 89% (P = .016). The gradient was significantly reduced after implantation (94.5 ± 36.5 vs 46.4 ± 26.7mmHg; P < .0001) and at final follow-up (94.5 ± 36.5 vs 35.9 ± 24.0mmHg; P < .0001). Mitral regurgitation permanently improved in 52% of the patients (P < .0001). There were no differences in ventricular thickness or diameters, ejection fraction, or diastolic function.

CONCLUSIONS

Sequential pacing in selected patients with obstructive hypertrophic cardiomyopathy improves functional class and reduces dynamic gradient and mitral regurgitation immediately after pacemaker implantation and at final follow-up. Prolonged ventricular pacing has no negative effects on systolic or diastolic function in these patients.

Dramatic improvement of refractory anemia caused by mechanical hemolysis in a patient with hypertrophic obstructive cardiomyopathy using dual-chamber pacing

A 59-year-old woman with hypertrophic obstructive cardiomyopathy was admitted to our institution with worsening heart failure. She developed mechanical intracardiac hemolysis due to left ventricular outflow tract (LVOT) obstruction. Despite surgical myectomy, the LVOT pressure gradient (PG) remained high and hemolytic anemia recurred. A dual-chamber implantable cardioverter defibrillator was then implanted, which decreased the LVOT-PG and improved hemolysis.

Abnormal left ventricular contraction sequence in hypertrophic cardiomyopathy patients: first description of hypersynchrony and invert synchrony

The aim of this study was to compare left ventricular contraction sequence in patients with hypertrophic cardiomyopathy (HCM) and healthy controls. Normal left ventricular contraction sequence in healthy controls exhibits an apex-to-base delay (ABD) contributing to efficient cardiac mechanics (physiologic asynchrony). Echocardiographic data from 20 controls and 40 HCM patients were prospectively analyzed. Endocardial longitudinal and circumferential strains and ABD were measured using custom-built software. HCM patients had increased circumferential (-36.4 ± 6.0 vs. -32.9 ± 5.0, p < 0.01) and decreased longitudinal (-19.3 ± 6.4 vs. -23.4 ± 5.7, p < 0.01) strains. In controls, physiologic ABD was observed (35.7 ± 18.1 ms). This delay was reduced in HCM patients (5.5 ± 22.7 ms, p < 0.01 vs. controls). There was no interaction between ABD and common clinical or echocardiographic parameters in the HCM population. Left ventricular contraction sequence can be modified in HCM patients, with the loss of the physiologic ABD. This phenomenon is independent from commonly measured parameters.

Comparison of long-term effect of dual-chamber pacing and alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy

Introduction. Nonpharmacological treatment of patients with hypertrophic obstructive cardiomyopathy (HOCM) comprises surgical myectomy (SME), alcohol septal ablation (ASA), and dual-chamber (DDD) pacing. The aim of the study was to compare the long-term effect of DDD pacing and ASA in symptomatic HOCM patients. Patients and Methods. We evaluated retrospective data from three cardiocenters; there were 24 patients treated with DDD pacing included and 52 treated with ASA followed for 101 ± 49 and 87 ± 23 months, respectively. Results. In the group treated with DDD pacing, the left ventricle outflow tract gradient (LVOTG) decreased from 82 ± 44 mmHg to 21 ± 21 mmHg, and NYHA class improved from 2.7 ± 0.5 to 2.1 ± 0.6 (both P < 0.001). In the ASA-treated group, a decline in LVOTG from 73 ± 38 mmHg to 24 ± 26 mmHg and reduction in NYHA class from 2.8 ± 0.5 to 1.7 ± 0.8 were observed (both P < 0.001). The LVOTG change was similar in both groups (P = 0.264), and symptoms were more affected by ASA (P = 0.001). Conclusion. ASA and DDD pacing were similarly effective in reducing LVOTG. The symptoms improvement was more expressed in patients treated with ASA.

Pacing for drug-refractory or drug-intolerant hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a genetic disease with an autosomal-dominant inheritance for which negative inotropes are the most widely used initial therapies. Observational studies and small randomised trials have suggested symptomatic and functional benefits using pacing and several theories have been put forward to explain why. Pacing, although not the primary treatment for HCM, could be beneficial to patients with relative or absolute contraindications to surgery or alcohol ablation. Several randomised controlled trials comparing pacing to other therapeutic modalities have been conducted but no Cochrane-style systematic review has been done.

OBJECTIVES

To assess the effects of pacing in drug-refractory or drug-intolerant hypertrophic cardiomyopathy patients.

SEARCH METHODS

We searched the following on the 14/4/2010: CENTRAL (The Cochrane Library 2010, Issue 1), MEDLINE OVID (from 1950 onwards ), EMBASE OVID (from 1980 onwards ), Web of Science with Conference Proceedings (from 1970 onwards). No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials of either parallel or crossover design that assess the beneficial and harmful effects of pacing for hypertrophic cardiomyopathy were included. When crossover studies were identified, we considered data only from the first phase.

DATA COLLECTION AND ANALYSIS

Data from included studies were extracted onto a pre-formed data extraction paper by two authors independently. Data was then entered into Review Manager 5.1 for analysis. Risk of bias was assessed using the guidance provided in the Cochrane Handbook. For dichotomous data, relative risk was calculated; and for continuous data, the mean differences were calculated. Where appropriate data were available, meta-analysis was performed. Where meta-analysis was not possible, a narrative synthesis was written. A QUROUM flow chart was provided to show the flow of papers.

MAIN RESULTS

Five studies (reported in 10 papers) were identified. However, three of the five studies provided un-usable data. Thus the data from only two studies (reported in seven papers) with 105 participants were included for this review. There was insufficient data to compare results on all-cause mortality, cost effectiveness, exercise capacity, Quality of life and Peak O2 consumption.When comparing active pacing versus placebo pacing on exercise capacity, one study showed that exercise time decreased from (13.1 ± 4.4) minutes to (12.6 ± 4.3) minutes in the placebo group and increased from (12.1 ± 5.6) minutes to (12.9 ± 4.2) minutes in the treatment group (MD 0.30; 95% CI -1.54 to 2.14). Statistically significant data from the same study showed that left ventricular outflow tract obstruction decreased from (71 ± 32) mm Hg to (52 ± 34) mm Hg in the placebo group and from (70 ± 24) mm Hg to (33 ± 27) mm Hg in the active pacing group (MD -19.00; 95% CI -32.29 to -5.71). This study was also able to show that New York Heart Association (NYHA) functional class decreased from (2.5 ± 0.5) to (2.2 ± 0.6) in the inactive pacing group and decreased from (2.6 ± 0.5) to (1.7 ± 0.7) in the placebo group (MD -0.50; 95% CI -0.78 to -0.22).When comparing active pacing versus trancoronary ablation of septal hypertrophy (TASH), data from one study showed that NYHA functional class decreased from (3.2 ± 0.7) to (1.5 ± 0.5) in the TASH group and decreased from (3.0 ± 0.1) to (1.9 ± 0.6) in the pacemaker group. This study also showed that LV wall thickness remained unchanged in the active pacing group compared to reduction from (22 ± 4) mm to (17 ± 3) mm in the TASH group (MD 0.60; 95% CI -5.65 to 6.85) and that LV outflow tract obstruction decreased from (80 ± 35.5) mm Hg in the TASH group to (49.3 ± 37.7) mm Hg in the pacemaker group.

AUTHORS' CONCLUSIONS

Trials published to date lack information on clinically relevant end-points. Existing data is derived from small trials at high risk of bias, which concentrate on physiological measures. Their results are inconclusive. Further large and high quality trials with more appropriate outcomes are warranted.

Interventional treatments for hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disorder. This autosomal dominant condition is defined by left ventricular hypertrophy and associated with functional limitation and premature death. In fact, many individuals are asymptomatic and the annual mortality in most modern series is 1% or less. However, severe symptoms may develop at any age, and the risk of premature death from arrhythmia, stroke, and progressive systolic impairment may complicate asymptomatic disease. The clinical management of patients with HCM therefore encompasses (1) genetic counseling including discussion of indications for genetic testing and cascade family screening, (2) assessment of prognostic risk from ventricular arrhythmia, stroke, and heart failure, and (3) symptom management. This article describes the interventional treatments in the management of severe symptoms associated with left ventricular outflow tract obstruction (LVOTO).

Device therapy in hypertrophic cardiomyopathy

With increasing awareness of the condition and particular attention being paid to family screening, the number of patients being diagnosed with hypertrophic cardiomyopathy is increasing. Although the majority of patients remain at low risk for sudden cardiac death, all patients need to undergo rigorous and ongoing risk factor stratification in order to best identify those at high risk. Although implantable cardioverter-defibrillators have proven to be effective in the prevention of sudden cardiac death, careful consideration of device implantation in high-risk patients is necessary in view of the potential for device complications and their impact on quality of life.

Reviews of Translational Medicine and Genomics in Cardiovascular Disease: New Disease Taxonomy and Therapeutic Implications

The enduring subdivision of cardiomyopathies into hypertrophic (HCM), dilated (DCM), and restrictive (RCM) categories reflects the emphasis of traditional classifications on morphology. Rapid advances in the genetic interrogation of these disorders have redefined their taxonomy and revealed potential conflicts between the old and new classifications. Hypertrophic cardiomyopathy has been redefined as a disease of perturbed sarcomere function. Dilated cardiomyopathy is a disease that results from more varied perturbations, including, but not limited to, defects of the cytoskeleton. Positional cloning and candidate gene approaches have been successful in identifying >40 disease loci, many of which have led to disease genes in HCM, DCM, RCM, and arrhythmogenic right ventricular cardiomyopathy. These findings provide mechanistic insights, permit genetic screening, and to a limited extent, facilitate prognostication. Although single gene analyses rapidly focus down to the underlying mechanistic pathways, they do not take account of all relevant variation in the human genome. Correspondingly, advances in genomics, through microarrays, have facilitated characterization of these broader downstream elements. As well as refining the taxonomic reclassification of cardiomyopathies, these genomic approaches, coupled with functional studies, have identified novel potential therapeutic targets, such as cardiac energetics, calcium handling, and apoptosis. We review the successes and pitfalls of genetic and genomic approaches to cardiomyopathy and their impact on current and future clinical care.

Pacing in adults with congenital heart disease

Adults with congenital heart disease constitute one of the fastest growing populations in cardiology. Pacing is an integral part of their therapy and may reduce their morbidity and mortality significantly. The current generation of pacemakers is more sophisticated and complex, and they are being utilized for indications other than conduction abnormalities, such as termination of tachycardia and improvement of heart failure. The complex anatomy and history of multiple previous surgeries in adults with congenital heart disease, however, pose many limitations and technical challenges related to the placement of a pacemaker. Unique and innovative approaches to endocardial lead placement and improved epicardial leads is making pacemaker implantation more feasible in these patients.

Junctional rhythm in hypertrophic cardiomyopathy: a case report

We observed a case of a 47-year-old male patient with hypertrophic cardiomyopathy and family history of sudden death. During cardiac catheterization, the patient presented spontaneous intermittent atrioventricular junctional rhythm without significant changes related to sinus heart rate. The gradient was absent with sinus beats, but the junctional rhythm induced the appearance of a left ventricular-aorta gradient, with parallel reduction of aortic pressure from 156 to 120 mm Hg. Subsequently, a couple of pre-mature ventricular beats induced an important post-extrasystolic potentiation of the gradient, followed in the last beats by sinus rhythm with disappearance of the gradient. Our case suggests that the decrease of left ventricular volume, due to the absence of an effective atrial systole, leads to left ventricular increased gradient, not imputable to an increased inotropic effect or heart rate modifications but to the decrease of pre-load.

Surgical outcomes and strategy of hypertrophic obstructive cardiomyopathy

OBJECTIVE

To evaluate the surgical clinical results of hypertrophic obstructive cardiomyopathy.

METHODS

We retrospectively collected data on 24 patients who underwent surgical management in the past ten years in two hospitals in China and Madras Medical Mission in India. Myomectomy was carried out on all patients. Among them 3 patients underwent mitral valve replacement; 2 patients underwent mitral valve repair (anterior mitral leaflet plication); 2 patients underwent aortic valve replacement; 1 patient underwent aortic valve repair; 2 patients underwent aortic root replacement; 1 patient underwent Bentall's procedure and 1 patient underwent coronary artery bypass grafting because of a breached muscle bridge.

RESULTS

One patient died of post-operative heart failure. The mean follow-up time was 4.3 years. There was significant improvement in the symptomatic status. Sixteen patients were asymptomatic with good effort tolerance and only four patients had New York heart association (NYHA) Classes I-II due to associated valvular lesions.

CONCLUSION

Our experience proved that symptomatic hypertrophic obstructive cardiomyopathy or non-symptomatic hypertrophic obstructive cardiomyopathy with combined heart disease is indication for surgery as surgical intervention could get better clinical results in this kind of patients compared with other non-surgical method because it beneficially reduces the systolic anterior motion (SAM) of the mitral valve leaflet, which could not be avoided by other non-surgical treatment.

Pacemaker-induced mitral regurgitation as a cause of refractory congestive heart failure during pacing therapy in a patient with hypertrophic obstructive cardiomyopathy

This report describes a woman with hypertrophic obstructive cardiomyopathy in whom initial hemodynamic improvement by dual chamber (DDD) pacing with short atrioventricular delay was excellent, but severe mitral regurgitation developed during the subsequent follow-up period, resulting in refractory congestive heart failure. There were two possible explanations for the origin of the complicating mitral regurgitation in this patient: pacing-induced semiclosure of the mitral valve, or left ventricular asynchrony caused by right ventricular pacing. Heart failure in patients with hypertrophic obstructive cardiomyopathy who undergo placement of a DDD pacemaker to improve not only mitral regurgitation but also heart failure symptoms can be associated with systolic mitral regurgitation as the cause of failure in DDD pacing therapy.