Use of different catheter ablation technologies for treatment of typical atrial flutter: acute results and long-term follow-up.

OBJECTIVES: We report the acute success and long-term follow-up in consecutive patients undergoing catheter ablation of typical right atrial flutter (AFL) using different ablation technologies. METHODS: One hundred and two patients presenting for treatment of AFL to our laboratory were included in the study. Based on availability and physician preference, ablation was performed with either a cooled-tip catheter (39 patients, group I), an 8- or 10-mm tip catheter connected to a high-power radiofrequency (RF) generator (25 patients, group II), or a 4- or 5-mm tip catheter (38 patients, group III). Acute ablation success was achieved in all group II and group III patients. Among the 38 patients undergoing ablation with the conventional catheter tip (group I), crossover to an 8-mm tip or a cooled tip ablation catheter was required in 11 patients (29%). The mean fluoroscopy time was significantly higher in group I (54.3 +/- 26.4 minutes) when compared to group II (39.6 +/- 19.6 minutes; P < 0.05) and group III (40 +/- 16 minutes; P = 0.0.5). After a mean follow up of 20 +/- 5 months no patient in group II experienced recurrence of AFL, whereas 18.4% (7 of 38 patients; P < 0.05) in group I and 10% (4 of 39 patients; P < 0.05) in group III had recurrence of AFL. Ablation technologies designed to obtain larger size lesions appeared to be more effective in achieving acute ablation success of AFL and in limiting the long-term recurrence rate of this arrhythmia.

Nonexcitatory stimulus delivery improves left ventricular function in hearts with left bundle branch block.

INTRODUCTION: Preliminary data in a heart failure animal model and isolated muscle preparation have suggested that nonexcitatory stimulation (NES) improves left ventricular (LV) function. METHODS AND RESULTS: We compared biventricular (BV) pacing with NES in an animal model with left bundle branch block (LBBB). The left bundle branch (LBB) was ablated in eight normal heart pigs and led to >50% increase in QRS duration (mean 100 +/- 15 msec). End-diastolic LV pressure, end-systolic LV pressure, LV pressure (LV dP/dtmax), aortic pulse pressure, and LV ejection fraction were measured before pre-LBB ablation and compared with post-LBB ablation (AAI pacing), BV pacing, NES delivery, and BV+NES. Moreover, to evaluate LV diastolic function, we measured the early (E wave) and late flows (A wave) through the mitral valve using spectral Doppler. Compared with post-LBB ablation, NES led to a significant increase in LV dP/dtmax (1,047 +/- 224 mmHg/sec vs 897 +/- 116 mmHg/sec; P < 0.05), LV ejection fraction (64% +/- 18% vs 49% +/- 17%; P < 0.05), and aortic pulse pressure (18 +/- 3.6 mmHg vs 16 +/- 2.8 mmHg; P < 0.05). Moreover, improvement in LV hemodynamic parameters was significantly higher during NES delivery when compared with BV pacing. No significant changes in E wave, A wave, and E/A were recorded during NES, NES+BV, and BV pacing. CONCLUSION: Our preliminary data demonstrate that NES is superior to BV pacing in improving LV function in an animal model with LBBB. Moreover, we demonstrated that NES does not affect transmitral valve flow and subsequently LV diastolic function.

Circular mapping and ablation of the pulmonary vein for treatment of atrial fibrillation: impact of different catheter technologies.

OBJECTIVES: We conducted this study to compare the efficacy and safety of different catheter ablation technologies and of distal versus ostial pulmonary veins (PV) isolation using the circular mapping technique. BACKGROUND: Electrical isolation of the PVs in patients with atrial fibrillation (AF) remains a technical challenge. METHODS: Two hundred eleven patients (163 men; mean age 53 +/- 11 years) with symptomatic AF were included in this study. In the first 21 patients (group 1), distal isolation (> or = 5 mm from the ostium) was achieved targeting veins triggering AF. In the remaining 190 patients (group 2), ostial isolation of all PVs was performed using 4-mm tip (47 patients), 8-mm tip (21 patients), or cooled-tip (122 patients) ablation catheters. RESULTS: Distal isolation was able to eliminate premature atrial contractions (PACs) and AF in six of 21 patients (29%) and 10 of 34 PVs. After a mean follow-up time of 6 +/- 4 months, no patients treated with the 8-mm tip catheter experienced recurrence of AF, whereas 21% (10 of 47 patients) and 15% (18 of 122 patients) of the patients ablated with the 4-mm tip and the cooled-tip ablation catheters experienced recurrence of AF after a mean follow-up of 10 +/- 3 and 4 +/- 2 months, respectively. Significant complications including stroke, tamponade, and severe stenosis occurred in 3.5% (8/211) of patients. CONCLUSIONS: Catheter technologies designed to achieve better lesion size appeared to have a positive impact on procedure time, fluoroscopy time, number of lesions, and overall efficacy. Although distal isolation can be achieved with fewer lesions, ostial isolation is required in the majority of patients to eliminate arrhythmogenic PACs and AF.