Routine ambulatory heart rhythm monitoring for detection of atrial arrhythmias in transthyretin cardiac amyloidosis.

BACKGROUND: Atrial fibrillation and flutter (AF/AFL) are common in transthyretin cardiac amyloidosis (ATTR-CM) which in turn is associated with higher risk of thromboembolism. Detecting AF/AFL may be especially important, but the role of routine ambulatory monitoring in ATTR-CM patients is unclear. OBJECTIVE: The objective is therefore to determine prevalence and outcomes of subclinical AF/AFL on routine ambulatory rhythm monitoring. METHODS: We report outcomes of an observational study of patients at our Amyloidosis Center with wild-type or variant ATTR-CM diagnosed between 2005 and 2019. Patients without known AF/AFL at baseline had ambulatory ECG monitoring (duration 2-30 days) every 6 months while those with cardiovascular implantable electronic devices (CIEDs) had device interrogations instead. RESULTS: Eighty-four patients with ATTR-CM (mean age 73.5 ± 9.7 years, 94% male) had mean follow-up 2.3 ± 1.9 years. Forty patients (48%) had AF/AFL before ATTR-CM diagnosis. In the remainder, 21 (48%) were subsequently diagnosed with AF/AFL: 10 (48%) based on symptoms, and 11 (52%) by monitoring. Anticoagulation (AC) was started in 9/11 (82%) patients with incidental AF/AFL. Among the entire cohort, stroke occurred in 9 patients (11%): 1 hemorrhagic and 8 ischemic (7 in patients with AF/AFL). No strokes occurred in patients on AC. CONCLUSION: Almost half of patients in our cohort had AF/AFL diagnosed prior to their ATTR-CM diagnosis. In the remainder, approximately half of AF/AFL diagnoses were established incidentally by routine monitoring, most of whom were promptly anticoagulated. Incidence of stroke was high overall, but no strokes occurred in anticoagulated patients. Optimal frequency and duration of monitoring needs further investigation.

Mode of death and outcomes of implantable cardioverter defibrillators in transthyretin amyloid cardiomyopathy.

INTRODUCTION: Transthyretin cardiac amyloidosis (ATTR-CM) may associate with sudden cardiac death. We report on the mode of death and outcomes with implantable cardioverter defibrillators (ICDs) in a cohort with ATTR-CM. METHODS: A single center observational cohort study of patients with ATTR-CM diagnosed between 2005 and 2019. ICD implant was at discretion of treating cardiologists. Medians are expressed with 25th,75th percentiles. RESULTS: Eighty-four patients with ATTR-CM (age 73.5 ± 9.7 years, 94% male, median follow-up 21.1 months (11.4-38.1). Nineteen patients (23%) underwent ICD implantation - 18 for primary and 1 for secondary prevention. In the primary prevention ICD group, 1 patient had 2 inappropriate shocks, 1 patient had appropriate ATP on 3 occasions. One patient (mixed ischemic cardiomyopathy and ATTR-CM) with secondary prevention ICD had 15 appropriate shocks in 3 episodes of VT storm. In patients without ICD, ambulatory monitoring review (14,764 h) did not reveal sustained ventricular arrhythmia. Excluding the one patient with secondary prevention ICD, 5 (28%) in the primary prevention ICD group and 22 (34%) in the non-ICD group died, p = 0.14. Mode of death did not vary between both groups. CONCLUSIONS: Patients with ATTR-CM and primary prevention ICD infrequently receive appropriate device therapy without differing in mode of death, which was mainly related to progressive heart failure, compared to those without ICD.

Perioperative Amiodarone to Prevent Atrial fibrillation after Septal Myectomy in obstrUctive hypeRtroPHic cardiomyopathy.

AIMS: Amiodarone reduces the incidence of atrial fibrillation (AF) following coronary artery bypass surgery; however, the benefit of perioperative amiodarone in patients undergoing septal myectomy (SM) for obstructive hypertrophic cardiomyopathy (oHCM) has not been studied. We hypothesized that prophylactic amiodarone would reduce the incidence of postoperative AF (POAF) following SM for oHCM. METHODS AND RESULTS: A single-centre, pre-post intervention open-label study of oral amiodarone (200 mg twice daily starting 7 days preoperatively and 200 mg once daily continuing for 30 days postoperatively) in patients without prior AF undergoing SM for oHCM from 2014 to 2018. The primary outcome was incident AF within 30 days. Secondary outcomes were unplanned readmission, AF treatment, total and intensive care unit (ICU) length of stay (LOS), and pacemaker implantation for high-grade atrioventricular (AV) block. 61 patients met inclusion criteria with 34 (55.8%) in the pre-intervention (control) group and 27 (44.2%) in the post-intervention (amiodarone) group. The incidence of POAF was 11.0% in the amiodarone group compared with 38.2% in the control group (P = 0.017). After adjusting for age, amiodarone was associated with less POAF [adjusted odds ratio (aOR) 0.21; 95% confidence interval (CI) 0.05, 0.76; P = 0.016]. ICU (2 days [IQR 1, 4] vs. 3 days [IQR 2, 4]; P = 0.165) and total (6 days [IQR 5, 6] vs. 6 days [IQR 5, 7]; P = 0.165) LOS were similar, as was the rate of pacemaker implantation (7.4% vs. 8.3%, P > 0.999). There were no adverse events associated with amiodarone. CONCLUSIONS: Perioperative oral amiodarone is safe and was associated with lower incidence of POAF following SM for oHCM.

Management Strategies for Atrial Fibrillation and Flutter in Patients with Transthyretin Cardiac Amyloidosis.

Atrial fibrillation (AF) and flutter (AFL) frequently complicate transthyretin cardiac amyloidosis (ATTR-CM). Management poses challenges as rate control drugs are poorly tolerated and data addressing tolerability and efficacy of rhythm control is limited. We report outcomes of AF/AFL in ATTR-CM in a single center observational study of patients seen at our Amyloidosis Center with wild-type or hereditary ATTR-CM diagnosed between 2005-2019 including 84 patients (average age 74 ± 10 years, 94% male) with 27.6 ± 22.8 months follow-up. AF/AFL occurred in 61 patients (73%). Rapid ventricular response was common as was attempted rate control. However, discontinuation of rate control drugs was frequent (80%), often for adverse effects. Rhythm control was attempted in 64%, usually with cardioversion (DCCV) or ablation. Post-DCCV recurrence was common (91%) and time to recurrence was similar with or without anti-arrhythmic drugs (5.8 months (IQR 1.9-12.5) vs 6.2 months (IQR 1.9-12.5) p = 0.83). Ablation was performed in 23% with AFL (all for typical AFL) with 14% recurrence after mean of 60.9 months. Ablation for AF was performed in 12% with 86% recurrence after median of 6.2 months (IQR 5.6-12.3). Most patients (62%) with rhythm control had subjective improvement (≥1 NYHA class or resolved palpitations). In conclusion, AF/AFL was common in our cohort. Rate control was poorly tolerated and often abandoned. Rhythm control led to symptomatic improvement in a majority of cases, but durable success was limited. DCCV was modestly successful and not significantly improved with anti-arrhythmics. Ablation was successful with typical AFL but had limited success in AF.

Prevalence and Outcomes of p.Val142Ile TTR Amyloidosis Cardiomyopathy: A Systematic Review.

BACKGROUND: The p.Val142Ile variant, predominantly found among people of African descent, is the most common cause of variant transthyretin amyloidosis and carriers predominantly develop a cardiomyopathy (variant transthyretin amyloidosis cardiomyopathy) phenotype. Yet, there are conflicting data on the prevalence and outcomes of p.Val142Ile variant carriers. METHODS: We performed a systematic review of the prevalence and outcomes of p.Val142Ile variant transthyretin amyloidosis cardiomyopathy among subjects of African descent. We found 62 relevant articles after searching the MEDLINE databases from 1980 to 2020 that reported data for ≈150 000 subjects. RESULTS: The reported worldwide prevalence of the p.Val142Ile variant is 0.3% to 1.6% in the general population. Among people of African descent, the reported prevalence from all studies ranges from 1.1% to 9.8%, but for studies with >1000 subjects, it is 3% to 3.5%. The prevalence of the p.Val142Ile variant in a region is dependent on the reported percentage of subjects who are of African descent in that region. p.Val142Ile variant transthyretin amyloidosis cardiomyopathy typically presents in the seventh to eighth decade of life and the majority of cases reported were male, with 25% to 38% diagnosed with atrial fibrillation. It was associated with a longitudinally worse quality of life and a lower adjusted survival compared with other types of transthyretin amyloidosis cardiomyopathy. CONCLUSIONS: The p.Val142Ile variant is the most common variant of the transthyretin gene with most carriers being of African descent. The true penetrance is unknown but the p.Val142Ile variant is associated with increased rates of incident heart failure and portends a lower overall survival. Increased awareness could lead to earlier diagnosis and improved heart failure outcomes among those of African descent, which is of increasing importance given the advent of novel therapeutics for this disease.