In-Hospital Postoperative Atrial Fibrillation Indicates a Poorer Clinical Outcome after Myectomy for Obstructive Hypertrophic Cardiomyopathy

Major adverse cardiovascular events after modified morrow surgery in hypertrophic obstructive cardiomyopathy: A 12-year cohort study

OBJECTIVE

This study investigates the incidence and risk factors for major adverse cardiovascular events (MACE) in patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing modified Morrow surgery. It also aims to develop a predictive model for MACE to improve clinical risk assessment.

METHODS

This retrospective cohort study included 292 HOCM patients who underwent modified Morrow surgery. The primary endpoint was the incidence of MACE. Univariate and multivariate logistic regression were used to identify independent risk factors for MACE, and a predictive model was developed.

RESULTS

MACE occurred in 39.04 % of patients (114/292), with 4.7 % mortality (14/292), 3.1 % cardiac arrest, 2.7 % requiring intra-aortic balloon pump (IABP) support, and 1.0 % requiring extracorporeal membrane oxygenation (ECMO). Low cardiac output syndrome occurred in 19.2 %, atrial fibrillation in 18.2 %, and third-degree atrioventricular block (AVB) in 3.1 %. Key risk factors included age (OR = 1.044), eGFR (OR = 1.025), preoperative pulmonary hypertension >30 mmHg (OR = 2.274), interventricular septal thickness (OR = 1.084), MRI delayed enhancement (OR = 2.021), and postoperative leukocytosis (OR = 1.061). The predictive model demonstrated strong performance (AUC = 0.815, P < 0.001).

CONCLUSION

Patients with HOCM undergoing modified Morrow surgery are at high risk of MACE. Key risk factors include age, eGFR, pulmonary artery pressure, septal thickness, MRI delayed enhancement, and postoperative leukocytosis. A predictive model based on these factors aids in tailoring perioperative management.

Clinical Significance of Postoperative Atrial Fibrillation in Hypertrophic Cardiomyopathy Patients Undergoing Septal Myectomy

BACKGROUND

The optimal management of hypertrophic cardiomyopathy (HCM) patients with postoperative atrial fibrillation (POAF) after surgical myectomy remains unknown. We sought to investigate the association between POAF and atrial fibrillation (AF) or cardioembolic events during follow-up to bridge this gap.

METHODS

Patients undergoing surgical myectomy at 2 HCM referral centres in North America from 2002 to 2020 were included in this study. Patients with preoperative AF were excluded. POAF was defined as any episode of AF within 30 days after surgery.

RESULTS

Of 1176 patients, 375 (31.9%) had POAF. Age (adjusted hazard ratio [HR] 1.05, 95% confidence interval [CI] 1.03-1.06; P < 0.001), premyectomy left atrial diameter (LAD; adjusted HR 1.6, 95% CI 1.32-2.02; P < 0.001), and smoking (adjusted HR 1.60, 95% CI 1.17-2.20; P = 0.001) were associated with POAF on multivariable analysis. Of 934 patients with follow-up data, of duration 4.3 ± 4.1 years, AF was detected in 86 (9.2%). Only POAF (HR 4.20, 95% CI 2.44-7.23; P < 0.001), previous history of stroke (HR 4.81, 95% CI 1.63-14.17; P = 0.01), and postmyectomy LAD (HR 1.80, 95% CI 1.21-2.70; P = 0.004) were associated with AF incidence during follow-up. Cardioembolic events occurred in only 15 patients (1.6%). POAF was not associated with increased cardioembolic risk, with only 3 patients with POAF suffering such an event, all more than 4 years after surgery.

CONCLUSIONS

POAF is common in HCM patients undergoing myectomy and is a predictor of AF during follow-up. Over long-term follow-up, cardioembolic events are uncommon. These findings suggest that routine long-term anticoagulation for all HCM patients with postmyectomy AF is not justified after the initial postoperative period.

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.

Imaging in Hypertrophic Cardiomyopathy: Beyond Risk Stratification

A multimodality imaging evaluation in hypertrophic cardiomyopathy is often used for risk stratification. Recent developments in imaging have allowed for better diagnosis, prognosis, and decision-making for a variety of therapies from medical to interventional. Echocardiography and magnetic resonance have been integral in evaluating subtype, left ventricular function, tissue characterization, left atrial measurements, valvular function, and presence of left ventricular aneurysm and outflow tract obstruction. These factors have helped to quantify risk of atrial fibrillation and determine the likely usefulness of pharmacologic therapy and septal reduction therapy. This review covers these in detail.

High-Burden Premature Atrial Contractions Predict New-Onset Atrial Fibrillation After Surgical Septal Myectomy

Although increased premature atrial contractions (PACs) reportedly predict atrial fibrillation (AF) in both general and specific (e.g., patients with stroke) populations, early postoperative AF (POAF) risk in patients with increased PAC burden who require cardiac surgery remains unclear. We examined the correlation between different preoperative PAC burdens and POAF in patients with obstructive hypertrophic cardiomyopathy (OHCM) who underwent surgical treatment. We analyzed 304 consecutively admitted patients with OHCM without previous AF who underwent isolated septal myectomy between January 2015 and December 2018. All patients underwent preoperative 24-hour Holter electrocardiogram monitoring. PACs were present in 259 patients (85.20%) and absent in 45 patients (14.80%). According to the cut-off PAC number of 100 beats/24 hours, there were 211 patients (69.41%) with low-burden PACs and 48 patients (15.79%) with high-burden PACs. AF after septal myectomy occurred in 73 patients, which consisted of 3/45 in the non-PAC group (6.67%), 47/211 in the low-PAC-burden group (22.27%), and 23/48 in the high PAC burden group (47.92%). POAF incidence was higher in both low- and high-burden patients than in patients without PAC (p <0.01). Multivariate logistic regression analyses demonstrated that high-burden PACs (p = 0.02) and age (p <0.01) but not low-burden PACs (p = 0.22) independently predicted POAF in patients with OHCM. The area under the receiver operating characteristic curve for preoperative PACs was 0.72 (95% confidence interval 0.66 to 0.79, p <0.01, sensitivity: 68.49%, specificity: 69.26%). In conclusion, POAF incidence was significantly higher in patients with preoperative high-burden PACs and can predict POAF in patients with OHCM.

Ventricular Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy (Analysis Spanning 60 Years Of Practice): AJC Expert Panel

Surgical myectomy remains the time-honored primary treatment for hypertrophic cardiomyopathy patients with drug refractory limiting symptoms due to LV outflow obstruction. Based on >50 years experience, surgery reliably reverses disabling heart failure by permanently abolishing mechanical outflow impedance and mitral regurgitation, with normalization of LV pressures and preserved systolic function. A consortium of 10 international currently active myectomy centers report about 11,000 operations, increasing significantly in number over the most recent 15 years. Performed in experienced multidisciplinary institutions, perioperative mortality for myectomy has declined to 0.6%, becoming one of the safest currently performed open-heart procedures. Extended myectomy relieves symptoms in >90% of patients by ≥ 1 NYHA functional class, returning most to normal daily activity, and also with a long-term survival benefit; concomitant Cox-Maze procedure can reduce the number of atrial fibrillation episodes. Surgery, preferably performed in high volume clinical environments, continues to flourish as a guideline-based and preferred high benefit: low treatment risk option for adults and children with drug refractory disabling symptoms from obstruction, despite prior challenges: higher operative mortality/skepticism in 1960s/1970s; dual-chamber pacing in 1990s, alcohol ablation in 2000s, and now introduction of strong negative inotropic drugs potentially useful for symptom management.

Impact of obstructive sleep apnea on new-set atrial fibrillation after septal myectomy in patients with hypertrophic obstructive cardiomyopathy

Background

Obstructive sleep apnea (OSA) is associated with a higher prevalence of postoperative atrial fibrillation in patients who underwent cardiac surgery. However, whether OSA is a risk factor for postoperative atrial fibrillation after septal myectomy remains unclear. We hypothesized that OSA was associated with postoperative atrial fibrillation after septal myectomy.

Methods

A total of 99 patients with hypertrophic obstructive cardiomyopathy who underwent septal myectomy were included in our manuscript. Polysomnography was performed in all patients, and the heart rhythm was continuously monitored during the perioperative period.

Results

In the present study, 25 (25.3%) patients developed postoperative atrial fibrillation after septal myectomy. The prevalence of postoperative atrial fibrillation was significantly higher in patients with OSA and increased with the worsening severity of OSA. Notably, the apnea-hypoxia index was significantly higher in patients with postoperative atrial fibrillation among the different OSA groups. In receiver operating characteristic analysis, the area under the curve for the apnea-hypopnea index was 0.785 (95% CI: 0.684–0.887, P<0.001); an apnea-hypopnea index of 10.4 was the optimal cutoff point to predict postoperative atrial fibrillation. In the multivariable analysis, apnea-hypopnea index ≥10.4 (odds ratio: 6.29, 95% CI: 2.18–18.14, P=0.001), moderate-to-severe OSA (odds ratio: 4.88, 95% CI: 1.42–16.86, P=0.01), and left atrium diameter (odds ratio: 1.12, 95% CI: 1.03–1.22, P=0.01) were independent risk factors associated with postoperative atrial fibrillation after adjusting for relevant variables. However, the association between the diagnosis of OSA and postoperative atrial fibrillation was no longer statistically significant.

Conclusions

The severity of OSA reflected by the apnea-hypopnea index in patients with obstructive hypertrophic cardiomyopathy who underwent surgery is an independent risk factor for postoperative atrial fibrillation, which is associated with adverse clinical outcomes.

Triglyceride-Glucose Index Independently Predicts New-Onset Atrial Fibrillation After Septal Myectomy for Hypertrophic Obstructive Cardiomyopathy Beyond the Traditional Risk Factors

The triglyceride-glucose index is a valuable marker of insulin resistance. However, the predictive value of this index for postoperative atrial fibrillation in patients undergoing septal myectomy remains unclear. A total of 409 patients with hypertrophic obstructive cardiomyopathy who underwent septal myectomy were recruited in this study. The triglyceride-glucose index was calculated for all patients preoperatively. All patients underwent clinical data collection, blood sampling, and standard echocardiographic examinations during hospitalization. The prevalence of postoperative atrial fibrillation was approximately 15% in the present study. Multivariate logistic regression revealed that age (odds ratio [OR]: 1.053, 95% CI: 1.016-1.090, P = 0.004), hypertension (OR: 2.399, 95% CI: 1.228-4.686, P = 0.010), left atrial diameter (OR: 1.101, 95% CI: 1.050-1.155, P < 0.001), and triglyceride-glucose index (OR: 4.218, 95% CI: 2.381-7.473, P < 0.001) were independent risk factors for postoperative atrial fibrillation in patients undergoing septal myectomy. In receiver operating characteristic curve analysis, the triglyceride-glucose index could provide a moderate predictive value for postoperative atrial fibrillation after septal myectomy 0.723 (95% CI: 0.650-0.796, P < 0.001). Moreover, adding the triglyceride-glucose index to conventional risk factor model could numerically but not significantly increase our ability to predict postoperative atrial fibrillation (area under the receiver: 0.742 (0.671-0.814) vs. 0.793 (0.726-0.860), p = 0.065) after septal myectomy. In our retrospective cohort study, the triglyceride-glucose index was identified as an independent predictor of postoperative atrial fibrillation in patients undergoing septal myectomy.

State-of-the-Art Treatments for Atrial Fibrillation in Patients with Hypertrophic Cardiomyopathy

Atrial fibrillation (AF) and hypertrophic cardiomyopathy (HCM) are two very common clinical entities, which often occur simultaneously, giving a hard time to both patients and cardiologists. Myocyte hypertrophy, myocyte disarray and interstitial fibrosis in the left atrium (LA) predisposes to atrial arrhythmias due to modifications of the substrate that promote re-entry. AF is usually poorly tolerated due to the shortening of the diastolic time with rapid heart rates and the lack of the atrial contribution to the diastolic filling in patients who often have a previous diastolic dysfunction. AF onset frequently results in exercise intolerance and recurrent heart failure admissions and also has prognostic implications. Early maintenance of sinus rhythm appears as a worthy approach in these patients, especially when started early in the course of the disease. However, treatment with antiarrhythmic (AA) agents in HCM patients is less effective than in patients without the disease, and concerns regarding safety frequently limit the long-term adherence. Catheter ablation has limited efficacy in patients with persistent AF but can play an important role in patients with paroxysmal AF, emphasizing the importance of an accurate patient selection. The aim of this review is to provide an overview of the pathophysiology of combined HCM and AF and the principal pharmacological and non-pharmacological treatments recommended in this complex clinical scenario.

The preoperative glomerular filtration rate predicts new-onset postoperative atrial fibrillation in patients with hypertrophic obstructive cardiomyopathy who undergo isolated septal myectomy

Background

Few studies have focused on new-onset postoperative atrial fibrillation in patients with hypertrophic obstructive cardiomyopathy who have undergone septal myectomy. Therefore, we investigated the incidence and prognosis effects of postoperative atrial fibrillation following septal myectomy in patients with hypertensive obstructive cardiomyopathy. Additionally, we investigated the relationship of estimated glomerular filtration rate and postoperative atrial fibrillation.

Methods

Data from 300 patients with hypertrophic obstructive cardiomyopathy who underwent isolated surgical septal myectomy were collected from January 2012 to March 2018.

Results

The overall incidence of postoperative atrial fibrillation during hospitalization was 22.67% (68 of 300 patients). Patients with postoperative atrial fibrillation were older (P<0.001), had lower preoperative estimated glomerular filtration rate (P<0.001), and a larger preoperative left atrial diameter (P=0.038) compared to patients without. The preoperative estimated glomerular filtration rate predicted postoperative atrial fibrillation with sensitivity and specificity of 0.824 and 0.578 (P<0.001), respectively. Multivariate regression analyses showed that age [odds ratio (OR) =1.090, 95% confidence interval (CI): 1.034-1.110], an New York Heart Association functional class ≥ III (OR =2.985, 95% CI: 1.349-6.604), hypertension (OR =2.212, 95% CI: 1.062-4.608), a history of syncope (OR =3.890, 95% CI: 1.741-8.692), and the preoperative estimated glomerular filtration rate (OR =0.981, 95% CI: 0.965-0.996) were independent risk factors associated in the development of postoperative atrial fibrillation. Survival analysis showed that the incidence of long-term cardiovascular events was higher in the patients with postoperative atrial fibrillation than that in the patients without the condition (P<0.001).

Conclusions

The preoperative estimated glomerular filtration rate was a moderate predictor of postoperative atrial fibrillation after septal myectomy. Postoperative atrial fibrillation affected the early recovery and the long-term prognoses of patients with hypertrophic obstructive cardiomyopathy who underwent septal myectomy.

Early and late post-operative arrhythmias after surgical myectomy: 45 years of follow-up

AIMS

The aims of this study are to investigate the incidence and determinants of post-operative atrial arrhythmias, conduction disorders and mortality in hypertrophic obstructive cardiomyopathy (HOCM) patients undergoing transaortic myectomy.

METHODS AND RESULTS

This retrospective single-center study was conducted in 249 patients (median age 54 years [40-64], 42% female) undergoing transaortic myectomy. Post-operative atrial fibrillation (AF) was reported in 84 patients (33.7%), including 56 patients (22.5%) with de novo AF. Older age (HR = 1.027 (1.003-1.052), p = 0.029) and hypercholesterolemia (HR = 2.296 (1.091-4.832) p = 0.029) were independent predictors for de novo post-operative AF. Late post-operative AF and atrial flutter (AFL) occurred in 18.9% and 6.8% of the patients, respectively. De novo early post-operative AF increased the risk of late post-operative AF (HR = 3.138 (1.450-6.789), p = 0.004). Patients with a right bundle branch block had a higher risk of early-postoperative pacemaker implantation (p = 0.003, HR = 9.771 (2.195-43.505)). Higher age at time of surgery (HR = 1.053 (1.026-1.081), p < 0.001) was a predictor for late mortality (n = 47, 18.9%).

CONCLUSION

Early and late post-operative AF, AFL and other SVTs are common sequelae after myectomy and are associated with older age at surgery, history of AF and early post-operative AF. Early post-operative arrhythmias are not transient and periodic rhythm monitoring is therefore essential to initiate therapy as soon as possible.

Changes in left atrial function, left ventricle remodeling, and fibrosis after septal myectomy for obstructive hypertrophic cardiomyopathy

BACKGROUND

This study aimed to investigate the impact of septal myectomy on left atrial function, left ventricle remodeling, and fibrosis in patients with obstructive hypertrophic cardiomyopathy.

METHOD

From May 2012 to September 2016, preoperative cardiac magnetic resonance imaging of 507 adult patients who underwent septal myectomy at Fuwai Hospital was retrospectively collected. Until October 2019, 57 patients were followed up with postoperative cardiac magnetic resonance imaging at 11.9 months (interquartile range, 6.4-25.3). Preoperative and postoperative left atrium and left ventricle changes, as well as late gadolinium enhancement as a surrogate of myocardial fibrosis, were analyzed.

RESULTS

Patients with hypertrophic cardiomyopathy requiring myectomy showed increased left atrium volume, stroke volume, left ventricular ejection fraction, and left ventricle mass, as well as decreased left ventricle end-systolic volume. Echocardiography demonstrated that myectomy decreased the left ventricle outflow tract gradient, left atrium diameter, left ventricular ejection fraction, and posterior wall thickness. Postoperative cardiac magnetic resonance imaging showed that the minimal left atrium volume (P < .001), stroke volume (P = .009), left ventricle ejection fraction (P < .001), and left ventricle mass (166.9 [interquartile range, 135.8] vs 149.3 [interquartile range, 100.5] g, P < .001) decreased, whereas the left ventricle end-systolic volume (P = .001) and left atrium ejection fraction (37.9% ± 14.6% vs 47.8% ± 14%, P < .001) increased. However, left ventricle myocardial fibrosis, as detected by late gadolinium enhancement, still progressed after myectomy in patients with obstructive hypertrophic cardiomyopathy (15.2% ± 9.6% vs 18.6% [interquartile range, 21.6], P = .009).

CONCLUSIONS

Septal myectomy alleviated left ventricle hypertrophy and reversed left atrium and left ventricle remodeling in patients with obstructive hypertrophic cardiomyopathy. Late gadolinium enhancement in the left ventricle increased despite myectomy in patients with obstructive hypertrophic cardiomyopathy.