Improvement in left ventricular systolic function after successful radiofrequency his bundle ablation for drug refractory, chronic atrial fibrillation and recurrent atrial flutter

Abstract

Incessant supraventricular tachyarrhythmia may lead to a reversible impairment of left ventricular (LV) function. This issue was investigated in 10 patients (aged 64 ± 13 years) who underwent radiofrequency His bundle ablation for control of drug refractory, chronic atrial fibrillation (n = 9) and recurrent atrial flutter (n = 1). LV function was assessed by 2-dimensional guided M-mode echocardiography within 24 hours (baseline) and 49 ± 18 days (follow-up) after successful ablation, both during VVI pacing at 70 beats/min. Fractional shortening increased from 28 ± 9% at baseline to 35 ± 8% at follow-up (p = 0.006). This increase in fractional shortening was due to a significant reduction of end-systolic diameter from 41 ± 10 to 36 ± 10 mm (p = 0.02), whereas there was no appreciable change in end-diastolic diameter (56 ± 7 to 55 ± 10 mm; p = 0.5). These changes were substantially greater in patients with baseline impairment of LV function (fractional shortening <27%). Fractional shortening increased by 12% (p = 0.14) in patients with normal LV function (n = 5) and by 44% (p = 0.02) in those with impaired LV function at baseline (n = 5). The greater increase in fractional shortening in patients with preexisting LV impairment was due to a more pronounced decline in end-systolic dimensions (−11.9%; p = 0.08) compared with that of patients with normal LV function at baseline (−9.21%; p = 0.2). End-diastolic diameter showed no significant change in either group (−3.53% [p = 0.8] and −0.58% [p = 0.4]). These data show that chronic, rapid atrial fibrillation and flutter may lead to impairment of LV systolic function, which is reversible on control of the tachycardia by radiofrequency His ablation. The recovery of LV mechanics is substantially greater in patients with the more profoundly depressed LV function at initial evaluation.