Differentiating macroreentrant from focal atrial tachycardias occurred after circumferential pulmonary vein isolation.

BACKGROUND: Atrial tachycardias (ATs) are commonly observed following catheter ablation of atrial fibrillation (AF). The aim of this study was to identify ECG characteristics that differentiate focal from macroreentrant ATs after circumferential pulmonary vein isolation (CPVI). METHODS AND RESULTS: One hundred and twenty ATs that occurred after CPVI were mapped using a 3-dimensional mapping system in 87 patients with AF. Further ablation was performed to eliminate the ATs. The surface ECGs of 68 ATs in 41 consecutive patients (Group 1) were analyzed retrospectively to create diagnostic algorithms. The algorithms were tested in the second 46 consecutive patients (Group 2). Patients with macroreentrant AT had lower left atrial (LA) voltage than those with focal AT (1.3 ± 0.3 vs 1.5 ± 0.2 mV, P = 0.01). Focal AT had a higher incidence of a positive polarity in V6 compared with macroreentrant AT (88% vs 55%, P = 0.03). The positive amplitude of the flutter/P waves in V6 was higher for focal AT than macroreentrant AT. The cycle lengths of the focal ATs were longer than those for macroreentrant AT (296 ± 107 vs 244 ± 25 ms, P < 0.001). Right atrial macroreentrant AT had a higher incidence of a negative polarity in at least 1 precordial lead compared with LA macroreentry. The positive flutter waves in V1 could differentiate roof/mitral isthmus dependent from non-roof/mitral isthmus dependent macroreentry. This algorithm correctly differentiated the focal from macroreentrant ATs with a sensitivity of 94%, specificity of 91%, and predictive accuracy of 92% in Group 2. CONCLUSION: Different electrophysiological properties may facilitate the differentiation between macroreentrant and focal ATs after CPVI.

Comparison of cooled-tip versus 4-mm-tip catheter in the efficacy of acute ablative tissue injury during circumferential pulmonary vein isolation.

INTRODUCTION: Although several studies have reported the benefits of cooled-tip ablation for circumferential pulmonary veins isolation (CPVI), the acute change of substrate property and acute PV reconnection have not been well demonstrated. The aim of this study was to compare the cooled-tip with regular 4-mm-tip catheter in acute substrate change after CPVI and long-term efficacy. METHODS AND RESULTS: One hundred and fifty-six patients (115 males, age 53 +/- 12 years) who underwent CPVI for treatment of atrial fibrillation (AF) were included. Group A consisted of 52 patients with cooled-tip ablation, and group B consisted of 104 patients with 4-mm-tip catheter ablation. The bipolar voltage of circumferential lesions was obtained using a 3-dimensional (3D) mapping system (NavX) before and after CPVI. The electrical reconnections of 4 PVs were evaluated 30 minutes after CPVI using a circular catheter. Cooled-tip catheter caused more reduction of the electrical voltage in PV antrum, lower incidence of acute PV reconnection, inducibility of AF, and gap-related atrial tachyarrhythmia (AT). Less number of left atrial (LA) ablation line and ablation applications and less procedure time were found in cooled-tip group compared to 4-mm-tip group. No significant difference in the incidence of pain sensation and complication was observed between the 2 groups. At a 14-month follow-up, the recurrence rate in the cooled-tip group was lower than in the 4-mm group (13.5% vs 33.7%, P = 0.009). CONCLUSION: Cooled-tip catheter has a superior long-term outcome than the 4-mm-tip catheter in CPVI, which may be associated with the efficacy of transmural block and electrical isolation in PV antrum.

Comparison of outcome in catheter ablation of atrial fibrillation in patients with versus without the metabolic syndrome.

Previous studies have reported that metabolic syndrome (MS) is associated with the development of atrial fibrillation (AF). However, its impact on the atrial substrate properties and catheter ablation in patients with AF is still unclear. This study consisted of 282 patients with AF (216 with paroxysmal AF and 66 with nonparoxysmal AF) who underwent catheter ablation using a 3-dimensional mapping system (NavX). Detailed AF mapping (frequency analysis and complex fractionated electrographic mapping) was performed in 59 patients. The patients were classified on the basis of MS, which was defined according to the guidelines of the National Cholesterol Education Program Adult Treatment Panel III. Patients with MS had larger left atrial sizes, shorter fractionated intervals, and higher dominant frequencies compared with those without it. Higher incidences of complex fractionated atrial electrographic sites located in the left atrial appendage base, coronary sinus, and crista terminalis regions were found in patients with MS. Patients with MS had a higher incidence of recurrent AF compared with those without MS (55% vs 24%, p <0.001). A higher incidence of recurrent AF from non-pulmonary vein origins was observed in patients with MS compared with those without it (45% vs 20%, p = 0.037). In conclusion, MS is associated with larger left atrial size and an arrhythmogenic substrate, which may increase the risk for recurrence after the ablation of AF. Close follow-up with good control of any metabolic disturbances may be needed in patients with MS to improve their outcomes after AF ablation.