Does ablation of atrial fibrillation at the time of septal myectomy improve survival of patients with obstructive hypertrophic cardiomyopathy?

Treatment Strategies for Hypertrophic Cardiomyopathy: Surgical

Septal myectomy is a well-established procedure for septal reduction in patients with obstructive hypertrophic cardiomyopathy (HCM) who have not responded to medical treatment. The surgical approach is tailored to the unique pathophysiology and septal morphology of the patient. Extended transaortic myectomy is the standard procedure for patients with isolated subaortic obstruction, the most common type of HCM. However, transapical myectomy is a useful adjunct for patients with long or midventricular obstruction and is our preferred technique for ventricular enlargement in patients with severe symptomatic diastolic heart failure because of extensive apical hypertrophy. Septal myectomy provides excellent postoperative outcomes as regards symptom relief and functional improvement, and operative morbidity and mortality rates are low in experienced centers. This article summarizes our current surgical management of patients with HCM and details operative methods and outcomes.

Contemporary Surgical Management of Hypertrophic Cardiomyopathy

More than half of symptomatic patients with hypertrophic cardiomyopathy (HCM) have left ventricular outflow tract (LVOT) obstruction. Septal reduction therapy by septal myectomy can dramatically relieve exertional dyspnea, chest pain, and presyncope in properly selected patients and is an important management pathway for many patients. The distribution and degree of hypertrophy in patients with obstructive HCM are variable and, as discussed in this review, can influence clinical manifestations of the disease and surgical management. Subaortic septal hypertrophy is the most common phenotype of obstructive HCM associated with LVOT obstruction, but midventricular obstruction and apical hypertrophy may occur in isolation or in conjunction with subaortic septal hypertrophy. In many comprehensive HCM centers, transaortic septal myectomy is the preferred method of septal reduction therapy for symptomatic patients with obstructive HCM. Early surgical approaches aimed at alleviating left LVOT obstruction were hampered by a lack of understanding of the anatomy and pathophysiology of obstructive HCM. With the advent of Doppler echocardiography and, more recently, cardiac magnetic resonance imaging, surgeons can precisely assess the location and degree of obstruction, left ventricular size and function, and morphology and function of the mitral valve. This review discusses the current understanding of the role of septal myectomy in the management of patients with HCM and details contemporary operative methods.

Evolving Contemporary Management of Atrial Fibrillation in Hypertrophic Cardiomyopathy

Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM) with clinical and subclinical episodes occurring in nearly one-half of patients. AF in HCM historically has been characterized as a decisive disease complication associated with substantial risk for thromboembolic stroke and increased morbidity and mortality. However, there have been many advances in treatment strategy resulting in improved outcomes for this patient group. For example, stroke risk in HCM has been greatly reduced by using systemic oral anticoagulation initiated after the first clinical (symptomatic) AF episode, usually with preference given to direct anticoagulants over warfarin. In contrast, stroke risk scoring systems (such as CHA2DS2-VASc score) are not informative in HCM given the substantial potential for stroke events in patients with low scores, and therefore should not be used for anticoagulation decisions in this disease. A novel risk score specifically designed for HCM (HCM-AF score) can reliably identify most patients with HCM at risk for future AF. Although a strategy focused on controlling ventricular rate is effective in asymptomatic (or minimally symptomatic) patients with AF, restoring and maintaining sinus rhythm is required for most patients with marked AF symptom burden and impaired quality of life. Several antiarrhythmic drugs such as sotalol, disopyramide, and amiodarone, can be effective in suppressing AF episodes; albeit safe, long-term efficacy is supported by only limited data. Catheter AF ablation has emerged as an important treatment option for some patients, although freedom from AF after a single ablation is relatively low (35% at 3 years), multiple ablations and the concomitant use of antiarrhythmic drugs can control AF with more than two-thirds of patients maintaining sinus rhythm at 5 years. Surgical AF ablation with biatrial Cox-Maze IV performed as an adjunctive procedure during myectomy can reduce symptomatic AF episodes (70% of patients free from AF at 5 years). For the vast majority of patients who have HCM with AF, the implementation of contemporary therapies has allowed for improved quality of life and low HCM-related mortality.

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.

Patient-Reported Atrial Fibrillation Following Septal Myectomy for Hypertrophic Cardiomyopathy

BACKGROUND

Patient-reported outcomes are important metrics of medical and surgical care. In this study, we investigated the prevalence and risk factors of patient-reported postdischarge atrial fibrillation (AF) following septal myectomy for obstructive hypertrophic cardiomyopathy.

METHODS

Patients undergoing transaortic septal myectomy from August 2001 to January 2017 were contacted regarding postdischarge AF through questionnaire-based surveys sent at 3, 5, and 10 years post procedure. For each patient, the most recent survey response was analyzed.

RESULTS

Among 949 patients, 248 (26.1%) last responded at 3 years post procedure, 353 (37.2%) at 5 years, and 348 (36.7%) at 10 years. The overall incidence of patient-reported postdischarge AF was 34.4% (n=326), and at 3, 5, and 10 years, the incidences were 22.2%, 34.8%, and 42.5% (P<0.001). After multivariable adjustment, history of preoperative AF (OR 5.566, P<0.001), early postoperative AF within the first 30 days (OR 2.211, P<0.001), preoperative left atrial volume index (OR 1.014, P=0.005), postoperative right ventricular systolic pressure (OR 1.021, P=0.013), postoperative moderate or greater mitral valve regurgitation (OR 1.893, P=0.022), and preoperative septal thickness (OR 1.043, P=0.036) were independently associated with patient-reported postdischarge AF.

CONCLUSIONS

The incidence of patient-reported postdischarge AF increases with increasing length of follow-up after septal myectomy. We identified several risk factors for late postdischarge AF that were associated with chronicity of left ventricular outflow tract obstruction, and earlier intervention may mitigate late atrial arrhythmias.

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.

Clinical Efficacy and Safety of Cox-Maze IV Procedure for Atrial Fibrillation in Patients With Hypertrophic Obstructive Cardiomyopathy

Objective: Atrial fibrillation is the most prevalent persistent arrhythmia in patients with hypertrophic obstructive cardiomyopathy. Comparative analyses of the safety and effectiveness of septal myectomy with and without surgical ablation are limited. This study aimed to compare the outcomes of septal myectomy with and without the Cox-maze IV procedure in patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation. Methods: Ninety-four patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation who underwent septal myectomy were analyzed, we divided it into concomitant Cox maze surgery (Cox-maze group) and no concomitant Cox maze operation (no Cox-maze group). Freedom from atrial fibrillation recurrence and all-cause mortality after surgery were assessed. Results: Freedom from all-cause mortality after septal myectomy at 1, 3, and 5 years was 98.5 ± 1.5% each in the Cox-maze group and 90.8 ± 6.3%, 85.1 ± 8.1%, and 85.1 ± 8.1%, respectively, in the no Cox-maze group. Patients in the no Cox-maze group had lower survival, freedom from atrial fibrillation recurrence off antiarrhythmic drugs, and arrhythmia control rate (including patients with successful antiarrhythmic drug conversion) than those in the Cox-maze group (P = 0.046, P = 0.040, and P = 0.012, respectively). Patients who underwent the Cox-maze IV procedure had lower atrial fibrillation recurrence rate than those who did not (hazard ratio, 0.141; 95% confidence interval, 0.042-0.479; P = 0.002). Post-operative increases in left atrial diameters (hazard ratio, 1.099; 95% confidence interval, 1.024-1.179; P = 0.009) were associated with atrial fibrillation recurrence. Conclusions: The Cox-maze IV procedure combined with septal myectomy improved mid-term survival and reduced mid-term atrial fibrillation recurrence in patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation. The concomitant Cox-maze IV procedure was associated with a lower atrial fibrillation recurrence in patients with surgical hypertrophic obstructive cardiomyopathy and atrial fibrillation.

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.