Atrial Tachyarrhythmia Prevalence in Patients with Implantable Cardiac Resynchronization Defibrillators

BackgroundAlthough studied far less extensively than AF, device-detected atrial tachyarrhythmias (AT) have been associated with higher thromboembolism (TE) risk in heart failure (HF) patients. CHA2DS2-VASc is the gold standard for clinical prediction of TE risk in patients with AF. However, as new research defines the relationship between ATs and TE events, it is increasingly important to understand how traditional cardiovascular health factors correlate with AT prevalence and associated TE risk.ObjectiveThe goal of this analysis is to examine the incidence of ATs and TEs in patients with heart failure and identify associations with other cardiovascular health factors.MethodsThe data set was collected as part of the IMPACT study, a multicenter, randomized trial which utilized daily remote monitoring to identify ATs in subjects implanted with ICDs or CRT-Ds. All subjects had a CHADS2 risk score greater than or equal to 1. The analysis described herein utilized the IMPACT study data for HF patients implanted with a CRT-D device. NYHA score was assessed by a qualified clinical investigator at enrollment or within 7 days prior. All potential subjects with permanent AF at time of enrollment were excluded. Subjects were considered to have AT during follow-up if maximum daily burden was equal to or exceeded 1% (equal to 14.4 minutes).ResultsThe overall prevalence of AT was 22.6%, with 209 out of 925 CRT-D subjects evaluated over a mean follow up duration of 1.9 years. In comparison, 14.1% of the subjects had a history of atrial tachyarrhythmias prior to enrollment. The study group was 69% male with a mean age of 66 years and left ventricular ejection fraction (LVEF) of 27%. Subjects with AT had a mean of 45 events per study-year and burden of 5.2% over the study duration. In this data set, AT prevalence during follow-up appears to have a strong positive association with NYHA score, with a correlation coefficient of 0.96 (Figure 1). TE events occurred in 20 subjects (2.1%) at a rate of 1.1 event per 100 subject-years. TE event rate was not positively associated with NYHA score (correlation coefficient of -0.73).ConclusionThe overall trend between NYHA class and AT prevalence is consistent with results demonstrated in previous research findings which link AF prevalence to HF severity. Additional analysis is required to more fully understand the relationship between NYHA class and AT prevalence for HF subjects with an implanted CRT-D device. Although studied far less extensively than AF, device-detected atrial tachyarrhythmias (AT) have been associated with higher thromboembolism (TE) risk in heart failure (HF) patients. CHA2DS2-VASc is the gold standard for clinical prediction of TE risk in patients with AF. However, as new research defines the relationship between ATs and TE events, it is increasingly important to understand how traditional cardiovascular health factors correlate with AT prevalence and associated TE risk. The goal of this analysis is to examine the incidence of ATs and TEs in patients with heart failure and identify associations with other cardiovascular health factors. The data set was collected as part of the IMPACT study, a multicenter, randomized trial which utilized daily remote monitoring to identify ATs in subjects implanted with ICDs or CRT-Ds. All subjects had a CHADS2 risk score greater than or equal to 1. The analysis described herein utilized the IMPACT study data for HF patients implanted with a CRT-D device. NYHA score was assessed by a qualified clinical investigator at enrollment or within 7 days prior. All potential subjects with permanent AF at time of enrollment were excluded. Subjects were considered to have AT during follow-up if maximum daily burden was equal to or exceeded 1% (equal to 14.4 minutes). The overall prevalence of AT was 22.6%, with 209 out of 925 CRT-D subjects evaluated over a mean follow up duration of 1.9 years. In comparison, 14.1% of the subjects had a history of atrial tachyarrhythmias prior to enrollment. The study group was 69% male with a mean age of 66 years and left ventricular ejection fraction (LVEF) of 27%. Subjects with AT had a mean of 45 events per study-year and burden of 5.2% over the study duration. In this data set, AT prevalence during follow-up appears to have a strong positive association with NYHA score, with a correlation coefficient of 0.96 (Figure 1). TE events occurred in 20 subjects (2.1%) at a rate of 1.1 event per 100 subject-years. TE event rate was not positively associated with NYHA score (correlation coefficient of -0.73). The overall trend between NYHA class and AT prevalence is consistent with results demonstrated in previous research findings which link AF prevalence to HF severity. Additional analysis is required to more fully understand the relationship between NYHA class and AT prevalence for HF subjects with an implanted CRT-D device.