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

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 less than 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]).(ABSTRACT TRUNCATED AT 250 WORDS)