Pulmonary vein isolation for the treatment of atrial fibrillation in patients with impaired systolic function.

OBJECTIVES: We aimed to determine the safety and efficacy of pulmonary vein isolation (PVI) in atrial fibrillation (AF) patients with impaired left ventricular (LV) systolic function. BACKGROUND: To date, PVI has been performed primarily in patients with normal LV function. Yet, many AF patients have impaired LV systolic function. The outcomes of PVI in patients with impaired LV systolic function are unknown. METHODS: We included 377 consecutive patients undergoing PVI between December 2000 and January 2003. Ninety-four patients had impaired LV function (ejection fraction [EF] <40%), and they comprised the study group. The control group was the remaining 283 patients who had a normal EF. End points included AF recurrence and changes in EF and quality of life (QoL). RESULTS: Mean EF was 36% in our study group, compared with 54% in controls. After initial PVI, 73% of patients with impaired EF and 87% of patients with normal EF were free of AF recurrence at 14 +/- 6 months (p = 0.03). In the study group, there was a nonsignificant increase in EF of 4.6% and significant improvement in QoL. Complication rates were low and included a 1% risk of pulmonary vein stenosis. CONCLUSIONS: Although the AF recurrence rate after initial PVI in impaired EF patients was higher than in normal EF subjects, nearly three-fourths of patients with impaired EF remained AF-free. Although our sample size was nonrandomized, our results suggest PVI may be a feasible therapeutic option in AF patients with impaired EF. Randomized studies with more patients and longer follow-up are warranted.

Evidence of specialized conduction cells in human pulmonary veins of patients with atrial fibrillation.

UNLABELLED: Specialized Conducting Cells in Human PV. INTRODUCTION: Depolarizations similar to those from the sinus node have been documented from the pulmonary veins after isolation procedures. We assessed the hypothesis that sinus node-like tissue is present in the pulmonary veins of humans. METHODS AND RESULTS: Pulmonary vein tissue was obtained from five autopsies (four individuals with a history of atrial fibrillation and one without a history of atrial arrhythmias) and five transplant heart donors. Autopsy veins were fixed in formaldehyde and processed for light microscopy to identify areas having possible conductive-like tissue. Areas requiring additional study were extracted from paraffin blocks and reprocessed for electron microscopy. Donor specimens were fixed in formaldehyde for histologic sections and glutaraldehyde for electron microscopy. Myocardial cells with pale cytoplasm were identified by light microscopy in 4 of the 5 autopsy subjects. Electron microscopy confirmed the presence of P cells, transitional cells, and Purkinje cells in the pulmonary veins of these cases. CONCLUSION: Our report is the first to show the presence of P cells, transitional cells, and Purkinje cells in human pulmonary veins. Whether these cells are relevant in the genesis of atrial fibrillation requires further study.

Three-dimensional reconstruction of pulmonary veins in patients with atrial fibrillation and controls: morphological characteristics of different veins.

Multidetector computed tomography can be used to evaluate the anatomy of pulmonary veins (PVs) in patients with AF. The study evaluated two groups. Group 1 included 61 patients assessed following PV ablation with ultrasound of RF energy. Group 2 included 15 patients undergoing ablation for AF and 14 control subjects without a history of AF matched for age and sex. The anatomy of the PVs was analyzed in this group prior to the ablation and compared to controls. Computed tomography was used to measure the ostium of the left superior, left inferior, right superior, right inferior PVs, and the left atrial appendage size. In group 1, PV stenosis was seen in 14 (30%) of 46 patients undergoing ablation with RF energy and in none of the 15 patients receiving ablation with ultrasound energy. In group 2, the ostium size was not different between patients with AF and controls. Similarly, the ostium of the PV that appeared to trigger AF was not larger than the ostium of the remaining veins. A "clustering pattern" of PV branches near the right inferior PV ostium was seen in almost every patient, independent of the presence of the arrhythmia. Computed tomography frequently detects PV stenosis following RF ablation. Ultrasound ablation does not appear to result in PV narrowing. Overall, patients with AF do not have larger sizes of PV ostia. Multiple ramifications from the right inferior PV ostium is a common pattern and may represent a protective anatomic variant.

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.

Use of intracardiac echocardiography for prediction of chronic pulmonary vein stenosis after ablation of atrial fibrillation.

INTRODUCTION: Measurements of pulmonary vein (PV) flow with intracardiac echocardiography (ICE) immediately before and after PV isolation may be a useful method for predicting which patients will develop chronic PV stenosis. METHODS AND RESULTS: We assessed preablation and postablation flows in each of the four PVs using a phase-array ICE catheter in 95 patients (mean age 52 +/- 13) undergoing atrial fibrillation ablation. The ostium of each of the PVs was defined using angiography, electrical mapping, and ICE imaging. Ostial electrical isolation of all PVs was achieved using a 4-mm cooled-tip radiofrequency ablation catheter. Change in PV flow, when present, was examined as both an absolute value and as a percentage of the baseline flow. All patients underwent spiral computed tomography (CT) scans of the PVs 3 months after the procedure for detection of stenosis. The average preablation diastolic flows for the left superior, left inferior, right superior, and right inferior veins were 0.56, 0.54, 0.47, and 0.45 m/sec, respectively. These values increased to 0.74, 0.67, 0.58, and 0.59 m/sec postablation (P < 0.001). Of 380 PVs ablated, the CT scans revealed 2 (1%) with severe (>70%) stenosis, 13 (3%) with moderate (51%-70%) stenosis, and 62 (16%) with mild (< or = 50%) stenosis. The r value between flow and stenosis was only 0.09 (P = NS). CONCLUSION: Acute changes in PV flow immediately after ostial PV isolation do not appear to be a strong predictor of chronic PV stenosis.