Radiofrequency catheter modification of atrioventricular conduction successfully controlled ventricular rate without pathologic AV block in 74% of patients with refractory atrial fibrillation.
Observational (n=19)
Does radiofrequency catheter modification of atrioventricular conduction improve ventricular rate control in patients with atrial fibrillation refractory to drug therapy?
Radiofrequency modification of AV conduction is a feasible technique to control ventricular rate in refractory atrial fibrillation, though it carries a 21% risk of inadvertent complete AV block requiring pacing.
BACKGROUND: In some patients with atrial fibrillation, the ventricular rate may be difficult to control with medications. We evaluated a radiofrequency catheter technique to modify atrioventricular conduction in atrial fibrillation in order to control the ventricular rate without creating pathologic atrioventricular block. METHODS: We studied 19 consecutive patients with atrial fibrillation and uncontrolled ventricular rates refractory to drug therapy. They had had atrial fibrillation for a mean (+/- SD) of 5.5 +/- 4.9 years, had had 4.9 +/- 0.9 unsuccessful drug trials, and were 62 +/- 15 years old. Before the procedure, the maximal ventricular rate during exercise was 180 +/- 39 beats per minute. A total of 11 +/- 5 radiofrequency-energy applications were delivered to the posterior septal or midseptal right atrium, near the ostium of the coronary sinus. RESULTS: Successful control of the ventricular rate without pathologic atrioventricular block was achieved in 14 of the 19 patients (74 percent). Persistent third-degree atrioventricular block requiring a permanent pacemaker occurred inadvertently in four patients (21 percent). Atrioventricular conduction was intentionally ablated in one patient. The 14 patients who had successful modification of conduction had persistent reductions in maximal ventricular rate during exercise (rate at three months, 126 +/- 24 beats per minute; P < 0.01). These patients had resolution of symptoms related to rapid rates during 8 +/- 2 months of follow-up. One patient had a recurrence of a rapid ventricular rate but was again asymptomatic after a second modification procedure. One patient with dilated cardiomyopathy died suddenly, five months after a successful procedure. CONCLUSIONS: A catheter technique to modify atrioventricular conduction without creating pathologic atrioventricular block is feasible in the majority of patients with symptomatic atrial fibrillation and a rapid ventricular rate refractory to drug therapy.
Williamson et al. (1994) conducted an observational in Atrial fibrillation with uncontrolled ventricular rates (n=19). Radiofrequency catheter modification of atrioventricular conduction was evaluated on Successful control of the ventricular rate without pathologic atrioventricular block. Radiofrequency catheter modification of atrioventricular conduction successfully controlled ventricular rate without pathologic AV block in 74% of patients with refractory atrial fibrillation.