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Impact of PFO on LA Linear Ablation. Introduction: We investigated the impact of the mode of left atrial (LA) access via patent foramen ovale (PFO) versus transseptal (TS) puncture on LA linear lesions during atrial fibrillation (AF) ablation. Methods and Results: We investigated 139 (PFO: 25) consecutive patients who underwent mitral isthmus (MI) and/or LA roof linear ablation. Technical endpoint was completeness of linear lesions and duration of radiofrequency (RF) application. During the initial procedure, complete MI and LA roof blocks were created in 13 of 19 (68%) and 14 of 17 (82%) patients in the PFO group, and in 57 of 94 (61%) and 54 of 70 (74%) patients in the TS group, respectively (P = NS). There was no significant difference in RF durations at MI (11.1 ± 8.9 and 15.1 ± 7.6 minutes, P = 0.11), and LA roof (10.1 ± 3.5 and 8.3 ± 5.0 minutes, P = 0.21) between the 2 groups. Among 28 patients who underwent repeat linear ablation, complete MI and LA roof blocks were created in 3 of 4 (75%) and 0 of 1 (0%) patients in the PFO group, and in 16 of 21 (76%) and 7 of 10 (70%) patients in the TS group, respectively (P = NS). There was no significant difference in RF durations at MI (15.3 ± 8.3 and 19.5 ± 18.3 minutes, P = 0.71), and LA roof (19.0 and 10.3 ± 5.4 minutes, P = 0.19) between the 2 groups. Clinical outcomes at 12 months were also similar. Conclusion: There were no significant differences in the procedural success rates, durations of RF application, 12-month clinical outcomes, and complication rates of LA linear ablation between the PFO and TS groups. Accessing the LA via a PFO is not an unfavorable approach toward LA linear ablation. © 2011 Wiley Periodicals, Inc.

Background-Achievement of complete conduction block across left mitral isthmus (MI) is challenging. Anticipation of perimitral conduction time (PMCT) associated with MI block may expedite this procedure. We evaluated the relationship between the preprocedural variables and the quantum of PMCT in patients with bidirectionally blocked MI. Methods and Results-We reviewed clinical and echocardiographic parameters in 290 consecutive patients with confirmed bidirectional MI block during atrial fibrillation (AF) ablation. PMCT was defined as the temporal delay to the latest of the double potentials on the line of block while pacing posteroseptal to it in the left atrium (LA). LA size and type of AF significantly influenced PMCT in multivariate analysis. A cumulative score based on LA size (0≦45 mm; 1>45 mm) and type of AF (0: paroxysmal; 1=nonparoxysmal) ranged from 0 to 2. PMCT was directly correlated to the cumulative score (0: 169 ms; n=78; 95% confidential interval, 156 to 181); 1: 187 ms; n=103; 95% confidential interval, 178 to 196; 2: 209 ms; n=109; 95% confidential interval, 200 to 217). In 61 patients who underwent AF ablation twice, the difference between 2 PMCT values was <30 ms in 75% patients. Another consecutive 143 patients with and without MI block after at least 15 minutes of radiofrequency application were analyzed. Perimitral conduction delay <130 ms ruled out bidirectional MI block. Perimitral conduction delay >173 ms predicted bidirectional block with an accuracy of 86%. Conclusions-LA size and AF type significantly influence PMCT in patients undergoing successful MI ablation. These parameters can be used to predict the time value associated with MI block, preprocedurally. © 2011 American Heart Association, Inc.

Atrial fibrillation (AF) is the most common heart rhythm problem and a leading cause of morbidity and mortality. Serious complications associated with this disorder include cardioembolic stroke, heart failure, and death. The worldwide prevalence of AF is rapidly increasing owing to aging of the population. Abnormal impulse formation in the pulmonary veins is known to trigger paroxysmal AF and radiofrequency isolation of these veins is recommended in drug-refractory AF. Active pharmacological research is directed towards selectively targeting the culprit venous cells. Persistent AF is more likely to be an atrial disease. Intrinsic and extrinsic stressors are believed to cause electrostructural alterations in the atrial tissue leading to profibrillatory state. Further research will elucidate the role of stressors and help develop biomarkers to guide early management of AF. An ideal therapy for AF aims at prevention of onset and progression of AF and reduction of AF-related symptoms, hospitalization, stroke, and mortality.