Abstract 2314: Don’t Be Fooled by CRT Device Counters in Patients with AF: Common Presence of Ineffective Biventricular Capture as Determined by Sophisticated Holter Monitoring
BACKGROUND: Atrial fibrillation (AF) is present in a substantial minority of patients with advanced heart failure(HF). Despite special efforts in the setting of CRT devices, loss of sinus rhythm may result in a loss of resynchronization and contribute to non-response after CRT. In addition, the degree of effective biventricular(BIV) pacing may be overestimated by device counters due to presence of fusion and pseudofusion beats after loss of atrial synchronous pacing. The objective of this study was to determine the incidence of effective and ineffective paced beats in patients with AF and CRT devices with apparent high rates of capture, using a novel 12-lead Holter analysis program.
METHODS AND RESULTS: 8 unselected HF patients with chronic and rate-controlled AF and CRT device with > 90% BIV capture were fitted to a 12-lead Holter system (ROZINN Electronics, Inc.) for 24 hours. The Holter analysis program was capable of differentiating all forms of paced and spontaneous beats. The patients were 74±4.5 years, 80% male, NYHA class 3.0±1.2 and ischemic CM in 60%. All 8 patients had chronic AF and were treated with beta -blockers, digoxin and amiodarone. The CRT device counters revealed chronic BIV pacing of 95±4.8% (range 91–100%). After template-matched analysis of the entire 24 hours monitoring period (96089±7546 QRS complexes), the beats were categorized as complete capture, fused capture and pseudofusion. Only 3 of the 8 patients (37.5%) had >90% complete capture, and 5(82.5%) had <90% capture. Of these, 2 had 10.6 ± 6.7% fusion beats and 3 had 30.4 ± 10.9 % pseudofusion beats. The average ventricular response rate was 65±9 bpm. No demographic, clinical or treatment variable predicted incomplete capture.
CONCLUSIONS: Despite aggressive medical therapy and attention to careful CRT programming(rate smoothing, sensed RV pacing), a large proportion of patients with AF and HF have incomplete BIV capture due to fusion and pseudofusion beats. This pattern is not identified by the CRT device programmers, which give falsely elevated pacing percentages. It is likely that this pattern of ineffective pacing can contribute to poor response to CRT. AV junctional ablation may be needed in many patients with chronic AF and HF who require CRT in an effort to optimize clinical outcome