Outcomes of nonpharmacologic treatment of atrial fibrillation in patients with hypertrophic cardiomyopathy

Atrial Fibrillation Substrate and Catheter Ablation Outcomes in MYBPC3- and MYH7-Mediated Hypertrophic Cardiomyopathy

BACKGROUND

The effects of disease-causing MYBPC3 or MYH7 genetic variants on atrial myopathy, atrial fibrillation (AF) clinical course, and catheter ablation efficacy remain unclear.

OBJECTIVES

The aim of this study was to characterize the atrial substrate of patients with MYBPC3- or MYH7-mediated hypertrophic cardiomyopathy (HCM) and its impact on catheter ablation outcomes.

METHODS

A retrospective single-center study of patients with HCM who underwent genetic testing and catheter ablation for AF was performed. Patients with MYBPC3- or MYH7-mediated HCM formed the gene-positive cohort; those without disease-causative genetic variants formed the control cohort. High-density electroanatomical mapping was performed using a 3-dimensional mapping system, followed by radiofrequency ablation.

RESULTS

Twelve patients were included in the gene-positive cohort (mean age 55.6 ± 9.9 years, 83% men, 50% MYBPC3, 50% MYH7, mean ejection fraction 59.3% ± 13.7%, mean left atrial [LA] volume index 51.7 ± 13.1 mL/m2, mean LA pressure 20.2 ± 5.4 mm Hg) and 15 patients in the control arm (mean age 61.5 ± 12.6 years, 60% men, mean ejection fraction 64.9% ± 5.1%, mean LA volume index 54.1 ± 12.8 mL/m2, mean LA pressure 19.6 ± 5.41 mm Hg). Electroanatomical mapping demonstrated normal voltage in 87.7% ± 5.03% of the LA in the gene-positive cohort and 94.3% ± 3.58% of the LA in the control cohort (P < 0.001). Of the abnormal regions, intermediate scar (0.1-0.5 mV) accounted for 6.33% ± 1.97% in the gene-positive cohort and 3.07% ± 2.46% in the control cohort (P < 0.01). Dense scar (<0.1 mV) accounted for 5.93% ± 3.20% in the gene-positive cohort and 2.61% ± 2.19% in the control cohort (P < 0.01). Freedom from AF at 12 months was similar between the gene-positive (75%) and control (73%) cohorts (P = 0.92), though a greater number of procedures were required in the gene-positive cohort.

CONCLUSIONS

Patients with MYBPC3- or MYH7-mediated HCM undergoing AF ablation have appreciably more low-amplitude LA signals, suggestive of fibrosis. However, catheter ablation remains an effective rhythm-control strategy.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

Biatrial arrhythmogenic substrate in patients with hypertrophic obstructive cardiomyopathy

BACKGROUND

Atrial fibrillation (AF) in patients with hypertrophic obstructive cardiomyopathy (HOCM) may be caused by a primary atrial myopathy. Whether HOCM-related atrial myopathy affects mainly electrophysiological properties of the left atrium (LA) or also the right atrium (RA) has never been investigated.

OBJECTIVE

The purpose of this study was to characterize atrial conduction and explore differences in the prevalence of conduction disorders, potential fractionation, and low-voltage areas (LVAs) between the RA and LA during sinus rhythm (SR) as indicators of potential arrhythmogenic areas.

METHODS

Intraoperative epicardial mapping of both atria during SR was performed in 15 HOCM patients (age 50 ± 12 years). Conduction delay (CD) and conductin block (CB), unipolar potential characteristics (voltages, fractionation), and LVA were quantified.

RESULTS

Conduction disorders and LVA were found scattered throughout both atria in all patients and did not differ between the RA and LA (CD: 2.9% [1.9%-3.6%] vs 2.6% [2.1%-6.4%], P = .541; CB: 1.7% [0.9%-3.1%] vs 1.5% [0.5%-2.8%], P = .600; LVA: 4.7% [1.6%-7.7%] vs 2.9% [2.1%-7.1%], P = .793). Compared to the RA, unipolar voltages of single potentials (SPs) and fractionated potentials (FPs) were higher in the LA (SP: P75 7.3 mV vs 10.9 mV; FP: P75 2.0 mV vs 3.7 mV). FP contained low-voltage components in only 18% of all LA sites compared to 36% of all RA sites.

CONCLUSION

In patients with HOCM, conduction disorders, LVA, and FP are equally present in both atria, supporting the hypothesis of a primary atrial myopathy. Conceptually, the presence of a biatrial substrate and high-voltage FP may contribute to failure of ablative therapy of atrial tachyarrhythmias in this population.

Atrial Fibrillation in Patients with Hypertrophic Cardiomyopathy and Cardiac Amyloidosis: From Clinical Management to Catheter Ablation Indication

Atrial fibrillation (AF) is the most common arrhythmia in patients affected by cardiomyopathies. Reports estimate a prevalence of 27% in patients with hypertrophic cardiomyopathy (HCM) and 40% in patients with cardiac amyloidosis (CA). The presence of AF typically results in progressive functional decline, an increased frequency of hospitalizations for heart failure, and a higher thromboembolic risk. Medical management using mainly beta-blockers or amiodarone has produced variable outcomes and a high rate of recurrence. Catheter ablation reduces symptom burden and complications despite a moderate rate of recurrence. Recent evidence suggests that an early rhythm control strategy may lead to more favorable short- and long-term outcomes. In this review, we summarize contemporary data on the management of AF in patients with cardiomyopathy (HCM and CA) with particular reference to the timing and outcomes of ablation procedures.

Outcomes of concomitant surgical ablation in patients undergoing surgical myectomy for hypertrophic obstructive cardiomyopathy: A systematic review and meta-analysis

OBJECTIVE

Studies investigating the efficacy of concomitant surgical atrial fibrillation (AF) ablation in hypertrophic obstructive cardiomyopathy (HOCM) patients undergoing myectomy are scarce and limited in terms of sample size. We aim to summarize current outcomes of concomitant surgical AF ablation in HOCM patients undergoing surgical myectomy.

METHODS

This systematic review and meta-analysis was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We included all studies reporting any of the following outcomes of concomitant surgical AF ablation in HOCM patients: freedom from recurrence of AF, overall survival and complications. Outcomes were evaluated using traditional meta-analysis at given time-points and using pooled Kaplan-Meier curves.

RESULTS

A total of 13 studies were included, resulting in a total of 616 individual patients available for analysis. AF was paroxysmal in 68.1% of the patients (95% CI 56.0-78.2%; I2 = 87.1%; 8 studies, 583 participants). The majority of patients (86.2%) underwent either conventional Cox Maze III or IV (95% CI 39.7-98.3%; I2 = 92.4%; 8 studies, 616 patients) procedure. The incidence of early post-operative pacemaker implantation was 6.1% (95% CI 3.1-11.8%). Overall survival at 3, 5 and 7 years was 95.6% (95% CI 93.4-97.9%), 93.6% (95% CI 90.8-96.5%) and 90.5% (95% CI 86.5-94.6%), respectively. Freedom from recurrent AF at 3, 5 and 7 years was 77.6% (95% CI 73.7-81.7%), 70.6% (95% CI 65.8-75.7) and 63.2% (95% CI 56.2-73.8%), respectively.

CONCLUSION

This meta-analysis supports concomitant surgical AF ablation at the time of surgical myectomy in HOCM patients, as it seems to be safe and effective in terminating AF.

Efficacy and safety of dofetilide and sotalol in patients with hypertrophic cardiomyopathy

BACKGROUND

Professional society practice guidelines conflict regarding their recommendations of dofetilide (DOF) and sotalol (STL) for treatment of arrhythmias in hypertrophic cardiomyopathy (HCM), and supporting data is sparse. We aim to assess safety and efficacy of DOF and STL on arrhythmias in HCM.

METHODS

This was an observational study of HCM patients treated with DOF or STL for atrial fibrillation (AF) and ventricular arrhythmias (VA). Outcomes of drug discontinuation and arrhythmia recurrence were compared at 1 year and latest follow-up by Kaplan-Meier analysis. Predictors of drug failure were studied using uni- and multi-variable analyses. Drug-related adverse events were quantitated.

RESULTS

Here we show that of our cohort of 72 patients (54 ± 14 years old, 75% male), 21 were prescribed DOF for AF, 52 STL for AF, and 18 STL for VA. At 1 year, discontinuation and recurrence rates were similar for DOF-AF (38% and 43%) and STL-AF (29% and 44%) groups. Efficacy data was similar at long-term follow-up of 1603 (IQR 994-4131) days, and for STL-VA. Drug inefficacy was the most common reason for discontinuation (28%) followed by side-effects (13%). Incidences of heart failure hospitalization (5%) and mortality (3%) were low. One STL-AF patient developed non-sustained torsades de pointes in the setting of severe pneumonia and acute kidney injury, but there were no other drug-related serious adverse events.

CONCLUSIONS

DOF and STL demonstrate modest efficacy and satisfactory safety when used for AF and VA in HCM patients.

Catheter ablation of atrial fibrillation in hypertrophic cardiomyopathy: A proportional meta-analysis and systematic review of single-arm studies

Background

Atrial fibrillation (AF) is the most common arrhythmia in patients with hypertrophic cardiomyopathy (HCM). Limited data exists about the efficacy and clinical outcomes of AF ablation in HCM.

Objective

The purpose of this meta-analysis was to evaluate the role of catheter-based ablation for treatment of AF in patients with HCM.

Methods

PubMed, SCOPUS, Web of Science, Embase, Cochrane library, and ClinicalTrials.gov were searched for studies discussing outcomes of catheter-based ablation for AF in patients with HCM. Two reviewers independently screened studies and extracted relevant data. Incidence rate estimates from individual studies underwent logit transformation to calculate the weighted summary proportion under the random effect model.

Results

A total of 19 reports met the inclusion criteria (1183 patients). The single ablation procedure was successful in 39% patients. Up to 34% patients underwent a repeat ablation. About 41% patients in normal sinus rhythm after successful AF ablation received postprocedure antiarrhythmic drug (AAD) therapy. Patients undergoing successful AF ablation experienced a significant improvement in the New York Heart Association functional class (standardized mean difference -1.03; 95% confidence interval -1.23 to -0.83; P < .00001).

Conclusion

AF ablation appears to be safe and feasible in patients with HCM. Freedom from AF after undergoing successful ablation is associated with significant improvement in heart failure symptoms.

Efficacy of Catheter Ablation for Atrial Fibrillation in Hypertrophic Cardiomyopathy: A Systematic Review and Meta-Analysis

Atrial fibrillation (AF) is the most common arrhythmia in patients with hypertrophic cardiomyopathy (HCM). Catheter ablation (CA) has emerged as an effective therapy for AF. We conducted a meta-analysis to update the current clinical evidence on the efficacy of CA for AF in patients with HCM. We searched PubMed, Embase, Cochrane and Clinicaltrials.gov for interventional and observational studies assessing single and multiple procedure success rate of CA in HCM patients. Our meta-analysis included 25 studies involving 1817 patients. Success rate following single procedure was 40.4% (95% CI 33.1 to 48.0%) at latest follow-up. The pooled success rate following multiple procedures was 51.4% (95% CI 42.9% to 60.0%) at latest follow-up. In the subgroup analysis for AF subtype, TCA was more successful for paroxysmal AF compared to non-paroxysmal AF. For the subset of studies reporting drug-free success rate, single and multiple procedures had a success rate of 33.4% (95% CI 19.3 to 49.1%) and 51.8% (95% CI 41.3 to 62.2%) at latest follow-up, respectively. CA is a suitable option for AF in patients with HCM. Success rate is greater in paroxysmal AF, after multiple procedures and with antiarrhythmic drugs.

Atrial substrate characterization in patients with atrial fibrillation and hypertrophic cardiomyopathy: Evidence for an extensive fibrotic disease

INTRODUCTION

Data regarding the left atrial (LA) electroanatomical substrate in patients with hypertrophic cardiomyopathy (HCM) and atrial fibrillation (AF) are missing. In this electroanatomical mapping (EAM) study, we evaluated the extent of LA fibrosis and its impact on catheter ablation outcomes in patients with HCM and AF.

MATERIALS AND METHODS

High-density LA EAM was performed during AF in 28 consecutive patients with obstructive HCM and AF (42.9% displayed paroxysmal AF and 57.1% persistent AF). Propensity score (PS) matching analysis was performed to reduce the impact of potential confounding factors. PS were derived to match patients at a 1:1 ratio. Patients were matched according to age, sex and LA diameter. After PS, 28 non-HCM patients with AF were selected, and served as controls. Two different cut-off values of bipolar signal amplitude were investigated for fibrosis characterization (≤0.25 mV and ≤ 0.4 mV). HCM patients underwent pulmonary vein antral isolation (PVAI) and roof line, while non-HCM patients PVAI only.

RESULTS

After the 3-month blanking period, 10 HCM patients (35.7%) displayed atrial arrhythmia recurrence. HCM patients with arrhythmia recurrence showed significantly greater low voltage areas defined as either bipolar voltage ≤0.25 mV (22.5 ± 10% vs. 5.5 ± 6.4%, p = 0.001) or ≤ 0.4 mV (32 ± 13.9% vs. 5.9 ± 5.1%, p < 0.001). The presence of low voltage areas ≤0.4 mV greater than 14.1% of the total LA area also predicted arrhythmia recurrence with excellent sensitivity (100%) and specificity (100%). Univariate analysis revealed that the extent of LA fibrosis was the only predictor of AF recurrence. After PS matching with non-HCM patients, patients with HCM exhibited wider fibrotic regions ≤0.25 mV compared to non-HCM patients (p = 0.016).

CONCLUSIONS

High-density EAM reveals extensive LA fibrotic disease in patients with HCM, an event with certain implications in catheter ablation outcomes.

Atrial fibrillation management during septal myectomy for hypertrophic cardiomyopathy: A systematic review

INTRODUCTION

Atrial fibrillation is common in patients with hypertrophic cardiomyopathy, and significantly impacts mortality and morbidity. In patients with atrial fibrillation undergoing septal myectomy, concomitant surgery for atrial fibrillation may improve outcomes.

METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All studies reporting the outcomes of combined septal myectomy and atrial fibrillation surgery were included.

RESULTS

A total of 10 observational studies were identified, including 644 patients. Most patients had paroxysmal atrial fibrillation. The proportion with prior unsuccessful ablation ranged from 0 to 19%, and preoperative left atrial diameter ranged from 44 ± 17 to 52 ± 8 mm. Cox-Maze IV (n = 311) was the most common technique used, followed by pulmonary vein isolation (n = 222) and Cox-Maze III (n = 98). Patients with persistent or longstanding atrial fibrillation more frequently received Cox-Maze III/IV. Ranges of early postoperative outcomes included: mortality 0 to 7%, recurrence of atrial tachyarrhythmias 4.4 to 48%, cerebrovascular events 0 to 1.5%, and pacemaker insertion 3 to 21%. Long-term data was limited. Freedom from atrial tachyarrhythmias at 1 year ranged from 74% to 96%, and at 5 years from 52% to 100%. Preoperative predictors of late atrial tachyarrhythmia recurrence included left atrial diameter >45 mm, persistent or longstanding preoperative atrial fibrillation and longer atrial fibrillation duration.

CONCLUSION

In patients with atrial fibrillation undergoing septal myectomy, the addition of ablation surgery adds low overall risk to the procedure, and likely reduces the risk of recurrent atrial fibrillation in the long term. Future randomised studies comparing septal myectomy with or without concomitant AF ablation are needed.

Concomitant Cox-Maze IV and Septal Myectomy in Patients With Hypertrophic Obstructive Cardiomyopathy

BACKGROUND

In patients with hypertrophic obstructive cardiomyopathy, atrial fibrillation is associated with heart failure and increased late mortality. However, the role of surgical ablation in these patients is not well defined. The aim of this study was to evaluate the efficacy of the concomitant Cox-Maze IV procedure in patients undergoing septal myectomy for hypertrophic obstructive cardiomyopathy.

METHODS

Between 2005 and 2019, 347 patients who underwent septal myectomy at a single institution (Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, MO) were retrospectively reviewed. For patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation who underwent a concomitant Cox-Maze IV procedure, freedom from atrial tachyarrhythmias (ATAs) on or off antiarrhythmic drugs (AADs) was evaluated annually. Predictors of ATA recurrence were identified using Fine-Gray regression, with death as a competing risk.

RESULTS

A total of 42 patients underwent concomitant septal myectomy and Cox-Maze IV procedures. The majority of patients, 69% (29 of 42), had paroxysmal atrial fibrillation with a 2.5-year median duration. Operative mortality was 7% (3 of 42). New York Heart Association functional class was reduced after surgery (P < .01). Rates of freedom from recurrent ATAs at 1- and 5-year intervals were 93% (27 of 29) and 100% (14 of 14), respectively. Rates of freedom from ATAs and AADs were 83% (24 of 29) and 100% (14 of 14) at the same time points, respectively. Increased left atrial diameter predicted first ATA recurrence (P < .01). Cerebrovascular accident risk was lower in patients with atrial fibrillation who underwent concomitant Cox-Maze IV and septal myectomy relative to myectomy only (P = .02).

CONCLUSIONS

Late freedom from ATAs on or off AADs was excellent after Cox-Maze IV and septal myectomy. Although there was a higher than expected rate of perioperative complications, the study results suggest that concomitant surgical ablation should be considered in selected patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation.

Transcatheter ablation for atrial fibrillation in patients with hypertrophic cardiomyopathy: Long-term results and clinical outcomes

INTRODUCTION

Radiofrequency transcatheter ablation (RFCA) for atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM) has been proven feasible. However, the long-term results of RFCA and its impact on clinical course of HCM are unknown. The aim of this study was to analyse clinical outcomes and long-term efficacy of RFCA in a multicentre cohort of patients with HCM and concomitant AF.

METHODS

Patients with HCM and AF consecutively undergoing RFCA were included. Ablation failure was defined as recurrence of AF, atrial tachycardia, or flutter lasting more than 3 min and occurring after the blanking period.

RESULTS

Overall, 116 patients with symptomatic AF refractory to antiarrhythmic drugs were included. Over a median follow-up of 6.0 years (interquartile range: 3.0-8.9 years) recurrence rate after a single RFCA was 32.3 per 100 patient/years with 26% of patients free from AF relapses at 6-year follow-up. Among patients experiencing AF recurrence, 51 (66%) underwent at least one redo-procedure. The overall recurrence rate considering redo-procedures was 12.6 per 100 patients/years with 53% of patients free from AF relapses at 6 years. At last follow-up, with an average of 1.6 procedures, 67 (61%) patients were in sinus rhythm (SR). Patients remaining in SR showed better functional status compared with those experiencing arrhythmic recurrences (NYHA Class 1.6 ± 0.1 vs. 2.0 ± 0.1, p = .009).

CONCLUSIONS

RFCA of AF in HCM patients is an effective and safe strategy favoring long-term SR maintenance, reduction of atrial arrhythmic events, and improved functional status. However, most patients need repeat procedures and continuation of antiarrhythmic drugs.

Ablation of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy: Treatment Strategy, Characteristics of Consecutive Atrial Tachycardia and Long-Term Outcome

Background

Atrial fibrillation (AF) is common in patients with hypertrophic cardiomyopathy (HCM) and is associated with a deterioration of clinical status. Ablation of symptomatic AF is an established therapy, but in HCM, the characteristics of recurrent atrial arrhythmias and the long‐term outcome are uncertain.

Methods and Results

Sixty‐five patients with HCM (aged 64.5±9.9 years, 42 [64.6%] men) underwent AF ablation. The ablation strategy included pulmonary vein isolation in all patients and ablation of complex fractionated atrial electrograms or subsequent atrial tachycardias (AT) if appropriate. Paroxysmal, persistent AF, and a primary AT was present in 13 (20.0%), 51 (78.5%), and 1 (1.5%) patients, respectively. Twenty‐five (38.4%) patients developed AT with a total number of 54 ATs. Stable AT was observed in 15 (23.1%) and unstable AT in 10 (15.3%) patients. The mechanism was characterized as a macroreentry in 37 (68.5%), as a localized reentry in 12 (22.2%), a focal mechanism in 1 (1.9%), and not classified in 4 (7.4%) ATs. After 1.9±1.2 ablation procedures and a follow‐up of 48.1±32.5 months, freedom of AF/AT recurrences was demonstrated in 60.0% of patients. No recurrences occurred in 84.6% and 52.9% of patients with paroxysmal and persistent AF, respectively (P<0.01). Antiarrhythmic drug therapy was maintained in 24 (36.9%) patients.

Conclusions

AF ablation in patients with HCM is effective for long‐term rhythm control, and especially patients with paroxysmal AF undergoing pulmonary vein isolation have a good clinical outcome. ATs after AF ablation are frequently observed in HCM. Freedom of atrial arrhythmia is achieved by persistent AF ablation in a reasonable number of patients even though the use of antiarrhythmic drug therapy remains high.

2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This executive summary of the hypertrophic cardiomyopathy clinical practice guideline provides recommendations and algorithms for clinicians to diagnose and manage hypertrophic cardiomyopathy in adult and pediatric patients as well as supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from January 1, 2010, to April 30, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases.

STRUCTURE

Many recommendations from the earlier hypertrophic cardiomyopathy guidelines have been updated with new evidence or a better understanding of earlier evidence. This summary operationalizes the recommendations from the full guideline and presents a combination of diagnostic work-up, genetic and family screening, risk stratification approaches, lifestyle modifications, surgical and catheter interventions, and medications that constitute components of guideline directed medical therapy. For both guideline-directed medical therapy and other recommended drug treatment regimens, the reader is advised to follow dosing, contraindications and drug-drug interactions based on product insert materials.

2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

Aim This executive summary of the hypertrophic cardiomyopathy clinical practice guideline provides recommendations and algorithms for clinicians to diagnose and manage hypertrophic cardiomyopathy in adult and pediatric patients as well as supporting documentation to encourage their use. Methods A comprehensive literature search was conducted from January 1, 2010, to April 30, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Structure Many recommendations from the earlier hypertrophic cardiomyopathy guidelines have been updated with new evidence or a better understanding of earlier evidence. This summary operationalizes the recommendations from the full guideline and presents a combination of diagnostic work-up, genetic and family screening, risk stratification approaches, lifestyle modifications, surgical and catheter interventions, and medications that constitute components of guideline directed medical therapy. For both guideline-directed medical therapy and other recommended drug treatment regimens, the reader is advised to follow dosing, contraindications and drug-drug interactions based on product insert materials.

Utilization and Complications of Catheter Ablation for Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy

Background

Atrial fibrillation (AF) is common and bears a major clinical impact in patients with hypertrophic cardiomyopathy (HCM). We aimed to investigate the use and real‐world safety of catheter ablation for AF in patients with HCM.

Methods and Results

We drew data from the US National Inpatient Sample to identify cases of AF ablation in HCM patients between 2003 and 2015. Sociodemographic and clinical data were collected, and incidence of catheter ablation complications, mortality, and length of stay were analyzed, including trends between the early (2003–2008) and later (2009–2015) study years. Among a weighted total of 1563 catheter ablation cases in patients with HCM, the median age was 62 (interquartile range, 52–72), 832 (53.2%) were male, and 1150 (73.6%) were white. The average annual volume of AF ablations in patients with HCM doubled between the early and the later study period (79–156). At least 1 complication occurred in 16.1% of cases, and the in‐hospital mortality rate was 1%. Cardiac and pericardial complications declined from 8.8% to 2.3% and from 2.8% to 0.9%, respectively, between the early and the later study years (P<0.01). Independent predictors of complications included female sex (odds ratio [OR], 4.81; 95% CI, 2.72–8.51), diabetes mellitus (OR, 6.57; 95% CI, 2.68–16.09) and obesity (OR, 3.82; 95% CI, 1.61–9.06).

Conclusions

Despite some decline in procedural complications over the years, catheter ablation for AF is still associated with a relatively high periprocedural morbidity and even mortality in patients with HCM. This emphasizes the importance of careful clinical consideration, by an experienced electrophysiologist, in referring patients with HCM for an AF ablation.

Atrial Fibrillation in Hypertrophic Cardiomyopathy: Evidence-based Review About Mechanism, Complications and Management

Hypertrophic cardiomyopathy (HCM) is 1 of the most frequent genetic cardiovascular diseases affecting 1 out of every 500 individuals in general population. Atrial Fibrillation incidences were 3.8% per 100 patients per year and overall prevalence among HCM patients are 27.09%. Higher risk of death noted in HCM patients with atrial fibrillation. Stroke and other thrombo embolic risks are increased in such patients. Medical management using mainly betablockers or amiodarone produced variable results and high rate of recurrence. Catheter ablation reduced symptom burden and complications despite moderate recurrence. Patients with multiple repeated procedures found to have better success rate and outcomes. The complications are not high leading to increased feasibility of the procedure. More research using latest techniques in catheter ablation need to be studied.

Targeted Medical Therapies for Hypertrophic Cardiomyopathy

PURPOSE OF REVIEW

The management of hypertrophic cardiomyopathy (HCM) has changed considerably over the years, although molecular therapies targeting core mechanisms of the disease are still lacking. This review provides an overview of the contemporary medical approach to patients with HCM, and of promising novel developments hopefully soon to enter the clinical arena.

RECENT FINDINGS

Our perception of therapeutic targets for medical therapy in HCM is rapidly evolving. Novel approaches include myocardial metabolic modulation, late sodium current inhibition, and allosteric myosin inhibition, actively pursued to reduce and hopefully prevent the development of severe HCM phenotypes, improve symptom control, and preserve patients from disease-related complications. Clinical management of patients with HCM should be guided by in-depth knowledge of the complex mechanisms at the energetic, metabolic, and electrophysiologic level. Until new experimental therapies become available, tailored management of modifiable disease manifestations should be pursued, including lifestyle counseling and prevention of comorbidities.

Hypertrophic cardiomyopathy: the future of treatment

Hypertrophic cardiomyopathy (HCM) is a heterogeneous genetic disorder most often caused by sarcomeric mutations resulting in left ventricular hypertrophy, fibrosis, hypercontractility, and reduced compliance. It is the most common inherited monogenic cardiac condition, affecting 0.2% of the population. Whereas currently available therapies for HCM have been effective in reducing morbidity, there remain important unmet needs in the treatment of both the obstructive and non-obstructive phenotypes. Novel pharmacotherapies directly target the molecular underpinnings of HCM, while innovative procedural techniques may soon offer minimally-invasive alternatives to current septal reduction therapy. With the advent of embryonic gene editing, there now exists the potential to correct underlying genetic mutations that may result in disease. This article details the recent developments in the treatment of HCM including pharmacotherapy, septal reduction procedures, mitral valve manipulation, and gene-based therapies.

Research Needs and Priorities for Catheter Ablation of Atrial Fibrillation: A Report From a National Heart, Lung, and Blood Institute Virtual Workshop

Catheter ablation has brought major advances in the management of patients with atrial fibrillation (AF). As evidenced by multiple randomized trials, AF catheter ablation can reduce the risk of recurrent AF and improve quality of life. In some studies, AF ablation significantly reduced cardiovascular hospitalizations. Despite the existing data on AF catheter ablation, numerous knowledge gaps remain concerning this intervention. This report is based on a recent virtual workshop convened by the National Heart, Lung, and Blood Institute to identify key research opportunities in AF ablation. We outline knowledge gaps related to emerging technologies, the relationship between cardiac structure and function and the success of AF ablation in patient subgroups in whom clinical benefit from ablation varies, and potential platforms to advance clinical research in this area. This report also considers the potential value and challenges of a sham ablation randomized trial. Prioritized research opportunities are identified and highlighted to empower relevant stakeholders to collaborate in designing and conducting effective, cost-efficient, and transformative research to optimize the use and outcomes of AF ablation.

Atrial Fibrillation in Hypertrophic Cardiomyopathy: Diagnosis and Considerations for Management

Atrial fibrillation is common in hypertrophic cardiomyopathy with a prevalence of 22-32 %. The impact of atrial fibrillation on overall survival, left ventricular function, thromboembolic stroke and quality of life is crucial. This review enlightens incidence, pathophysiology, and clinical symptoms. Early recognition of atrial fibrillation is essential. Monitoring methods for early detection are described. Finally effective therapy options are discussed including oral anticoagulation and the role of interventional catheter-based ablation in the treatment of atrial fibrillation in HCM patients.

Clinical Profile and Consequences of Atrial Fibrillation in Hypertrophic Cardiomyopathy

Background:

Atrial fibrillation (AF), the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM), is capable of producing symptoms that impact quality of life and is associated with risk for embolic stroke. However, the influence of AF on clinical course and outcome in HCM remains incompletely resolved.

Methods:

Records of 1558 consecutive patients followed at the Tufts Medical Center Hypertrophic Cardiomyopathy Institute for 4.8±3.4 years (from 2004 to 2014) were accessed.

Results:

Of the 1558 patients with HCM, 304 (20%) had episodes of AF, of which 226 (74%) were confined to symptomatic paroxysmal AF (average, 5±5; range, 1 to >20), whereas 78 (26%) developed permanent AF, preceded by 7±6 paroxysmal AF episodes. At last evaluation, 277 patients (91%) are alive at 62±13 years of age, including 89% in New York Heart Association class I or II. No difference was found in outcome measures for patients with AF and age- and sex-matched patients with HCM without AF. Four percent of patients with AF died of HCM-related causes (n=11), with annual mortality 0.7%; mortality directly attributable to AF (thromboembolism without prophylactic anticoagulation) was 0.1% per year (n=2 patients). Patients were treated with antiarrhythmic drugs (most commonly amiodarone [n=103] or sotalol [n=78]) and AF catheter ablation (n=49) or the Maze procedure at surgical myectomy (n=72). Freedom from AF recurrence at 1 year was 44% for ablation patients and 75% with the Maze procedure ( P <0.001). Embolic events were less common with anticoagulation prophylaxis (4/233, 2%) than without (9/66, 14%) ( P <0.001).

Conclusions:

Transient symptomatic episodes of AF, often responsible for impaired quality of life, are unpredictable in frequency and timing, but amenable to effective contemporary treatments, and infrequently progress to permanent AF. AF is not a major contributor to heart failure morbidity or a cause of arrhythmic sudden death; when treated, it is associated with low disease-related mortality, no different than for patients without AF. AF is an uncommon primary cause of death in HCM virtually limited to embolic stroke, supporting a low threshold for initiating anticoagulation therapy.

Concomitant ablation for atrial fibrillation during septal myectomy in patients with hypertrophic obstructive cardiomyopathy

OBJECTIVE

The appearance of atrial fibrillation is associated with significant clinical deterioration in patients with obstructive hypertrophic cardiomyopathy; therefore, maintenance of sinus rhythm is desirable. Guidelines and most articles have reported the results of catheter ablation and pharmacologic atrial fibrillation treatment; nevertheless, data regarding concomitant procedures during septal myectomy are limited. The aim of this study was to assess the outcomes of concomitant atrial fibrillation treatment in patients with obstructive hypertrophic cardiomyopathy.

METHODS

Between 2010 and 2013 in our clinic, 187 patients with obstructive hypertrophic cardiomyopathy underwent extended myectomy. In 45 cases, concomitant Cox-Maze IV procedure was performed; however, obstructive hypertrophic cardiomyopathy was the primary indication for surgery. Atrial fibrillation was paroxysmal in 26 patients (58%) and nonparoxysmal in 19 patients (42%). The mean age of patients was 52.8 ± 14.2 years (range, 22-74 years). Mean peak gradient was 90.7 ± 24.2 mm Hg, and interventricular septum thickness was 26.1 ± 4.3 mm. Mean atrial fibrillation duration was 17.3 ± 8.5 months.

RESULTS

There were no early deaths. No procedure-related complications occurred with regard to ablation procedure. Complete atrioventricular block was achieved in 2 patients (4.0%). Mean crossclamping time was 61 ± 36 minutes. Peak left ventricular outflow tract gradient was 12.6 ± 5.5 mm Hg based on transesophageal echocardiography. The Maze IV procedure was used for ablation in all patients (radiofrequency ablation with bipolar clamp + cryolesion for mitral and tricuspid lines). Because of the atrial wall thickness (5-6 mm), applications were performed 8 to 10 times on each line. There were no cases of pacemaker implantation due to sinus node dysfunction. All patients were discharged in stable sinus rhythm. Mean follow-up was 23.7 ± 1.3 months. The rate of atrial fibrillation freedom was 100% (45 patients) at 6 months, 89% (40 patients) at 1 year, and 78% (35 patients) at 24 months.

CONCLUSIONS

Concomitant ablation atrial fibrillation during septal myectomy in patients with obstructive hypertrophic cardiomyopathy is a safe and effective procedure and should be considered carefully in this patient group.

Atrial Fibrillation in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is an inherited cardiac disorder with a spectrum of clinical manifestations. Patients with HCM are predisposed to developing atrial fibrillation (AF) due primarily to advanced diastolic dysfunction and left atrial (LA) dilatation and remodelling. Atrial fibrillation causes a progressive symptomatic and functional decline, as well as increased thromboembolic risk and mortality, particularly in the setting of rapid ventricular rates and left ventricular outflow tract (LVOT) obstruction. The mainstay of management of AF in HCM is a combination of non-pharmacological lifestyle and risk factor modification, long-term anticoagulation, and rhythm control with antiarrhythmic medications. There is a growing body of evidence indicating that an early and aggressive rhythm control strategy may result in more favourable outcomes.

Outcomes in hypertrophic cardiomyopathy patients with and without atrial fibrillation: a survival meta-analysis

BACKGROUND

Atrial fibrillation (AF) is a frequent occurrence in patients with hypertrophic cardiomyopathy (HCM). It is associated with worsening symptoms, cardiovascular events, and mortality. We conducted a meta-analysis of studies reporting on mortality in patient with HCM and AF.

METHODS

We searched PubMed, Medline, Embase, Ovid and Cochrane for studies which reported cardiovascular events and mortality in patients with HCM and AF. Outcome was a composite of cardiac mortality and/or all-cause mortality. Mantel Haenszel odds ratio (OR) or hazard ratio (HR) were calculated using random-effects meta-analysis for the prespecified outcome. Heterogeneity was assessed using I² statistics.

RESULTS

Six studies met the inclusion criteria. There were 6,858 patients; 1,314 (19%) had history of AF. During a mean follow up that ranged between 4 and 8 years, 405 (30.8%) patients with AF died as compared to 1,011 (18.2%) patients without AF (OR =2.49, 95% CI: 1.85-3.35, P<0.00001, I²=57%). Results persisted with inclusion of studies only reporting specifically on cardiac mortality (OR =2.80, 95% CI: 1.79-4.39, P<0.00001, I²=56%). Also, the mortality difference persisted after exclusion of deaths secondary to stroke in both groups (2 studies, 1,398 patients, OR =2.57, 95% CI: 1.57-4.20, P=0.0002, I²=31%). In three studies (5,857 patients); the presence of AF was associated with a pooled HR of 1.66 (95% CI: 1.29-2.13, P<0.0001, I²=41%).

CONCLUSION

Patients with HCM who develop AF have higher risk of mortality and cardiac deaths as compared to HCM patients without AF.

Who Needs Catheter Ablation And Which Approach?

Catheter ablation therapy for atrial fibrillation (AF) has gained a significant role during maintenance of sinus rhythm compared to anti-arrhythmic medication. Catheter ablation techniques are also improved and progressed over years in parallel to better understanding of disease mechanisms and technological advancements. However, due to invasive nature of the therapy with its pertinent procedural risks, both appropriate patient selection and use of relevant approach should be considered by all electrophysiologists before decide to perform catheter ablation.

Impact of Genotype on the Occurrence of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy

Genes associated with hypertrophic cardiomyopathy (HC) are not uniformly expressed in the atrial myocardium. Whether this may impact susceptibility to atrial fibrillation (AF) is unresolved. To analyze the prevalence and clinical correlates of AF in relation to genotype in a large HC cohort, prevalence and clinical profile of AF were assessed in 237 patients with HC, followed for 14 ± 10 years. Patients were divided into 3 genetic subgroups: (1) MYBPC3 (58%), (2) MYH7 (28%), and (3) "other genotypes" (14%; comprising TNNT2, TNNI3, TPM1, MYL2, complex genotypes, Z-line, and E-C coupling genes). Left atrial size was similar in the 3 subsets. AF occurred in 74 patients with HC (31%), with no difference among groups (31% in MYBPC3, 37% in MYH7 and 18% in other genotypes, p = 0.15), paroxysmal/persistent AF (12%, 18%, and 12%, respectively; p = 0.53), paroxysmal/persistent evolved to permanent (12%, 12%, and 3%, p = 0.36) or permanent AF (7%, 7%, and 3%, p = 0.82). Age at AF onset was younger in the group with other genotypes (37 ± 10 years) compared to the first 2 groups (53 ± 14 and 51 ± 17, respectively; p = 0.05) because of early onset associated with complex genotypes and a specific JPH2 mutation associated with abnormal intracellular calcium handling. At multivariate analysis, independent predictors of AF were atrial diameter (p ≤0.05) and age at diagnosis (p = 0.09), but not genetic subtype (p = 0.35). In conclusion, in patients with HC, genetic testing cannot be used in clinical decision making with regard to management strategies for AF. Genotype is not predictive of onset or severity of AF, which appears rather driven by hemodynamic determinants of atrial dilatation. Exceptions are represented by rare genes suggesting specific molecular pathways for AF in genetic cardiomyopathies.