Elsevier

American Heart Journal

Volume 164, Issue 4, October 2012, Pages 616-624
American Heart Journal

Clinical Investigation
Electrophysiology
Burden of atrial fibrillation and poor rate control detected by continuous monitoring and the risk for heart failure hospitalization

https://doi.org/10.1016/j.ahj.2012.06.020Get rights and content

Introduction

Atrial fibrillation (AF) on electrocardiogram has been identified as a risk factor for hospitalizations in patients with heart failure (HF). We investigated whether continuous AF monitoring can identify when patients with HF are at risk for hospitalization.

Methods

In this retrospective analysis of data from 4 studies enrolling patients with HF with cardiac resynchronization therapy defibrillator devices with ≥90 days of follow-up (n = 1561), patients were identified as having AF if they had ≥1 day of >5 minutes of AF and >1 hour of total AF during entire follow-up. In patients with AF, device recorded AF burden (AFb) and ventricular rate during AF (VRAF) over the last 30 days was classified on a monthly basis into 3 evaluation groups: (1) ≥1 day of high burden of paroxysmal AF (≥6 hours) or persistent AF (all 30 days with AFb >23 hours) with poor rate control (VRAF >90 beats/min), (2) ≥1 day of high burden of paroxysmal AF with good rate control (VRAF ≤ 90 beats/min), and (3) no days with high burden of AF (AFb <6 hours) or persistent AF with good rate control. Each group was compared with monthly evaluations in patients without AF using an Anderson-Gill model for occurrence of HF hospitalizations in the next 30 days.

Results

Patients with AF (n = 519, 33%) have a greater risk (hazard ratio [HR] 2.0, P < .001) for impending HF hospitalizations during entire follow-up compared with patients with no AF. One day of high burden of paroxysmal AF with good rate control in the last 30 days increases risk for HF hospitalization in the next 30 days (HR 3.4, P < .001). The risk increases further (HR 5.9, P < .001) with 1 day of poor rate control during persistent AF or high burden paroxysmal AF in last 30 days.

Conclusion

Evaluation of AFb and rate control information on a monthly basis can identify patients at risk for HF hospitalization in the next 30 days.

Section snippets

Background

In the United States, >2.2 million people have atrial fibrillation (AF) and >5.7 million have heart failure (HF).1 In patients hospitalized with AF, the most common primary diagnosis is HF.1 In patients with HF, AF is the most common arrhythmia.2, 3, 4 The Euro Heart Surveys showed that HF is present in 34% of patients with AF3 and AF is present in 42% of patients with HF.4 In patients with AF or HF, subsequent development of the other condition was associated with increased mortality.2 Atrial

Data set and event definitions

The retrospective analysis included data available from the PARTNERS-HF15 (N = 699 patients), FAST16 (N = 146 patients), OFISSER17 (N = 323 patients), Case Study Registry (N = 80 patients), and CONNECT18 (N = 313 patients) studies. PARTNERS-HF was a prospective observational study enrolling patients with CRT-D devices with EF ≤35%, New York Heart Association (NYHA) class III or IV, and QRS duration ≥130 ms. FAST was a prospective double-blinded observational study in patients with CRT-D or ICD

Results

A total of 1,561 patients with an average follow-up duration of 373 ± 146 days were used for this analysis. A total of 326 HF hospitalizations were identified in 207 patients (13%) providing an event rate of 0.2 per patient-year of monitoring. The baseline characteristics of the patients in the study are shown in the Table. Patients in the AF cohort were older and more likely to be males compared with patients with “no-AF.” No significant differences were observed for ejection fraction, history

Discussion

The study presented a retrospective data analysis to evaluate the ability of continuous AF monitoring to predict future HF hospitalizations. One day with high burden (>6 hours) of paroxysmal AF with good rate control in last 30 days (AFb + NVR group) increases the risk for HF hospitalization in the next 30 days. The risk increases further if there is 1 day of poor rate control during persistent AF or high burden paroxysmal AF (AFb + RVR group). Thus, a high burden of paroxysmal AF (>6 hours)

Conclusion

The current study identifies thresholds for creating different AFb and rate control groups and shows that evaluation of AFb and rate control information on a monthly basis can identify patients at risk for HF hospitalization in the next 30 days. Future studies are needed to validate the chosen threshold for categorizing different risk groups in a broader HF patient population and to evaluate whether timely intervention based on AF diagnostics can reduce cardiovascular hospitalizations in

References (35)

Cited by (40)

  • Standardized Definitions for Evaluation of Heart Failure Therapies: Scientific Expert Panel From the Heart Failure Collaboratory and Academic Research Consortium

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    This author group believes that multiple attributes of AF may be appropriate endpoints for use in a HF clinical trial, specifically both the presence of new or recurrent AF and the daily time burden of AF (63). AF lasting more than 6 h in a 24 h period identifies patients at greater risk of HF outcomes (64). Atrial fibrillation burden: Cumulative time spent in AF over a specified time period documented by a validated rhythm monitoring method.

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