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.

Emerging Therapies for Transthyretin Amyloidosis.

PURPOSE OF REVIEW: This review provides an overview of the available therapies for treating neuropathic and/or cardiac manifestations of transthyretin amyloidosis (ATTR), as well as investigational therapeutic agents in ongoing clinical trials. We discuss additional emergent approaches towards thwarting this life-threatening disease that until recently was considered virtually untreatable. RECENT FINDINGS: Advances in noninvasive diagnostic methods for detecting ATTR have facilitated easier diagnosis and detection at an earlier stage of disease when therapeutic interventions are likely to be more effective. There are now several ATTR-directed treatments that are clinically available, as well as investigational agents that are being studied in clinical trials. Therapeutic strategies include tetramer stabilization, gene silencing, and fibril disruption. ATTR has been historically underdiagnosed. With advances in diagnostic methods and the advent of disease-modifying treatments, early diagnosis and initiation of treatment is revolutionizing management of this disease.

Ventricular Septal Myectomy Decreases Long-Term Risk for Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy.

Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM) and is an important cause of morbidity and embolic stroke. The impact of outflow obstruction and the influence of surgical septal myectomy on the development of new-onset AF has not been well described. Consecutive patients with HCM without previous AF were followed for 5.0 ± 3.6 years for new-onset AF, including 717 with obstruction who did not undergo surgical myectomy (outflow gradients ≥30 mm Hg at rest or after provocation), 555 with nonobstructive HCM (outflow gradients <30 mm Hg), and 503 who underwent surgical myectomy. Patients with obstructive HCM who did not undergo myectomy had a 1.5-fold increased risk for new-onset AF compared with nonobstructive HCM (26% vs 16% at 10 years, hazard ratio = 0.69, p = 0.02). Patients who underwent myectomy had more advanced heart failure (95% vs 18% New York Heart Association class III, p <0.001) and had larger left atrium dimension (42 ± 7 vs 41 ± 7 mm; p <0.01) as compared with patients with obstructive HCM who did not undergo myectomy. However, after myectomy, the risk of new-onset AF was significantly lower than nonoperated obstructive (17% vs 26% at 10 years, p = 0.04) and no different from the risk of AF in patients with nonobstructive HC (hazard ratio 0.95, p = 0.81). In conclusion, patients with HCM with outflow obstruction are at a higher risk for AF compared with patients with nonobstructive HCM. However, after surgical myectomy, the risk for new-onset AF is substantially reduced. In addition to the known benefits of myectomy to permanently relieve outflow tract obstruction and mitral regurgitation, reverse heart failure symptoms, and increase longevity, myectomy is now shown to decrease susceptibility to AF in HCM.

Conduction Disturbances and Permanent Pacemaker Implantation After Transcatheter Aortic Valve Replacement: Predictors and Prevention.

Conduction disturbances and permanent pacemaker implantation (PPMI) remain a frequent and important consequence of transcatheter aortic valve replacement (TAVR). Understanding risk factors for TAVR-related conduction disturbances could improve patient selection, procedural techniques, and periprocedural efforts for monitoring and treatment of heart block. Several studies have identified patient-related and procedural factors associated with new-onset left bundle branch block, high-degree atrioventricular block, and the need for PPMI after TAVR. Notable patient-related predictors include preexisting right bundle branch block, membranous septal length, and calcification of the left ventricular outflow tract. Modifiable procedural predictors include device implantation depth, prosthesis oversizing, and valve type. This review aims to summarize the current literature examining predictors of conduction disturbances and PPMI after TAVR, particularly with regard to the newer-generation valve types. We also propose a management algorithm for the management of conduction disturbances postprocedure.

Novel Anatomic Predictors of New Persistent Left Bundle Branch Block After Evolut Transcatheter Aortic Valve Implantation.

New persistent left bundle branch block (NP-LBBB) has been associated with adverse outcomes after TAVI but few predictors thus far reported. We sought to identify predictors of NP-LBBB after TAVI with EvolutR/PRO (ER/EP). From 1/2016 to 4/2019, 544 patients from 2 centers underwent TAVI with Evolut (54% ER, 46% EP) for severe native aortic stenosis. Patients with previous LBBB and pacemaker were excluded. Aortic root analysis was performed using 3Mensio Valves Software and membranous septal length (MSL) was determined using the standard coronal view. Clinical, anatomic and procedural characteristics of 396 Evolut were analyzed and predictors of NP-LBBB were identified. Valve Academic Research Consortium-2 outcomes were reported. At discharge, NP-LBBB was seen in 76(19.2%) patients. NP-LBBB in Evolut was associated with implant depth at left coronary cusp (p = 0.004) and 34 mm ER (p = 0.026). Independent predictors of NP-LBBB in Evolut were shorter MSL (odds ratio [OR] = 0.82 per mm septum, 95% confidence interval [CI] = 0.68 to 0.98,p = 0.030), left ventricular outflow tract (LVOT) eccentricity (OR = 1.04 per %, 95% CI = 1.01 to 1.06,p = 0.002), implant depth at noncoronary cusp (NCC) (OR = 1.28 per mm ventricular, 95% CI = 1.11 to 1.48,p = 0.001) and annular perimeter oversizing ≥20% (OR = 2.38, 95% CI = 1.20 to 4.72, p = 0.013). On ROC curve analysis, MSL ≤6.5 mm, NCC depth ≥3 mm and LVOT eccentricity ≥35% were optimal threshold values to predict NP-LBBB. In Conclusion, shorter MSL, LVOT eccentricity, annular oversizing and deeper implant depth are novel predictors of NP-LBBB in Evolut TAVI. Preprocedural CT assessment of aortic root anatomy may help identify patients at risk for NP-LBBB. In such patients, modifying procedural factors such as higher implant and less annular oversizing may reduce the risk of NP-LBBB. Further evaluation of our hypothesis is warranted.