Notes: Introduction: There are currently no studies systematically evaluating pulmonary vein (PV) stenosis following catheter ablation of atrial fibrillation (AF) using the anatomic PV ablation approach. Methods and Results: Forty-one patients with AF underwent anatomic PV ablation under the guidance of a three-dimensional electroanatomic mapping system. Gadolinium-enhanced magnetic resonance (MR) imaging was performed in all patients prior to and 8–10 weeks after ablation procedures for screening of PV stenosis. A PV stenosis was defined as a detectable (≥3 mm) narrowing in PV diameter. The severity of stenosis was categorized as mild (〈50% stenosis), moderate (50–70%), or severe (〉70%). A total 157 PVs were analyzed. A detectable PV narrowing was observed in 60 of 157 PVs (38%). The severity of stenosis was mild in 54 PVs (34%), moderate in five PVs (3.2%), and severe in one PV (0.6%). All mild PV stenoses displayed a concentric pattern. Moderate or severe PV stenosis was only observed in patients with an individual encircling lesion set. Multivariable analysis identified individual encircling lesion set and larger PV size as the independent predictors of detectable PV narrowing. All patients with PV stenosis were asymptomatic and none required treatment. Conclusions: The results of this study demonstrate that detectable PV narrowing occurs in 38% of PVs following anatomic PV ablation. Moderate or severe PV stenosis occurs in 3.8% of PVs. The high incidence of mild stenosis likely reflects reverse remodeling rather than pathological PV stenosis. The probability of moderate or severe PV stenosis appears to be related to creation of individual encircling rather than encircling in pairs lesion.

Notes: Introduction: The aims of this study were to identify predictors of recurrence after catheter ablation of atrial fibrillation (AF) and to report the safety and efficacy of catheter ablation of AF using an irrigated-tip ablation catheter. Methods and Results: Seventy-five consecutive patients (51 men [68%]; age 54 ± 13 years) with symptomatic drug-refractory paroxysmal (42 patients), persistent (21 patients), or permanent (12 patients) AF underwent catheter ablation of AF using an irrigated-tip ablation catheter and a standard ablation strategy, which involved electrical isolation of all pulmonary veins (PVs) and creation of a cavotricuspid linear lesion. At 10.5 ± 7.5 months of follow-up following a single (n = 75) or redo ablation procedure (n = 11), 39 (52%) of the 75 patients were free of AF, 10 were improved (13%), and 26 had experienced no benefit from the ablation procedure (35%). Seventy-six percent of patients with paroxysmal AF were free from recurrent AF. The most significant complications were two episodes of pericardial tamponade, mitral valve injury in one patient, two strokes, and complete but asymptomatic PV stenosis in one patient. Cox proportional hazards multivariate regression analysis identified the presence of persistent AF, permanent AF, and age 〉50 years prior to the ablation are the only independent predictors of AF recurrence after the first PV isolation procedure. Conclusion: Catheter ablation of AF using a strategy involving isolation of all PVs and creation of a linear lesion in the cavotricuspid isthmus using cooled radiofrequency energy is associated with moderate efficacy and an important risk for complications. The best results of this procedure are achieved in the subset of patients who are younger than 50 years and have only paroxysmal AF. (J Cardiovasc Electrophysiol, Vol. 15, pp. 692-697, June 2004)

Notes: Introduction: Typical atrial flutter (AFL) can be cured by catheter ablation of the cavotricuspid isthmus (CTI). The surface electrocardiogram (ECG) is not always diagnostic of isthmus dependence of AFL. The aim of this study was to evaluate clinical parameters for the prediction of isthmus-dependent AFL. Methods and Results: Sixty consecutive adult patients without suspected atriotomy-related AFL, congenital heart disease, or previous AFL ablation, referred for catheter ablation of presumed typical AFL were studied. All patients had distinct flutter waves in the inferior leads, suggestive of CTI-dependent AFL, either on presentation to the electrophysiology (EP) lab or documented on prior ECG. Electrophysiology study was performed in the standard fashion. Patients who presented to the EP laboratory not in AFL underwent arrhythmia induction with a burst pacing protocol.A clinical history of persistent AFL (P = 0.0001) and existence of AFL on presentation to the EP laboratory (P = 0.0001) were strong predictors of CTI dependence. History of atrial fibrillation (P = 0.19), structural heart disease (P = 0.6), hypertension (P = 0.4), and previous cardiac surgery (P = 0.5), as well as the nature of AFL-related symptoms (P = 0.5), were not predictors of CTI-dependent AFL documented during EP study. Conclusion: In patients with ECG suggestive of typical AFL, the presence of persistent rather than paroxysmal AFL and presentation to the EP laboratory in AFL are strong predictors of CTI-dependent AFL. A paroxysmal pattern of AFL predicts noninducibility of CTI-dependent AFL during EP study. CTI ablation may therefore be less effective in these patients.

Notes: Introduction: Catheter ablation of the pulmonary veins (PVs) for prevention of recurrent atrial fibrillation requires precise anatomic information. We describe the characteristics of a new anatomic variant of PV anatomy using magnetic resonance angiography. Methods and Results: A 1.5-T magnetic resonance imaging system with a body coil or a torso phased-array coil was used before and after gadolinium injection. Magnetic resonance angiograms were acquired with a breath-hold three-dimensional fast spoiled gradient-echo imaging sequence in the coronal plane. Three-dimensional reconstruction with maximum intensity projections and multiplanar reformations was performed. A newly described variant PV ascending from the roof of the left atrium was found in 3 of 91 subjects. The mean ostial diameter of the roof PV was 7 ± 2 mm, the mean distance from the ostium to the first branching point was 22 ± 8.5 mm, and the mean distance to the right superior PV was 3.3 ± 0.6 mm. Conclusion: We refer to the newly described variant of PV anatomy as the “right top pulmonary vein.” It is important to be aware of this anatomic pattern to avoid inadvertent catheter intubation, which can result in misleading mapping results and PV stenosis. (J Cardiovasc Electrophysiol, Vol. 15, pp. 538-543, May 2004)

Notes: Introduction: Delineation of pulmonary vein (PV) anatomy is an integral part of the PV isolation procedure. The aims of the present study were to (1) describe the technique of selective PV angiography, (2) show the typical fluoroscopic locations and appearance of the PVs, and (3) compare the ostial diameters of PVs measured by angiography and magnetic resonance imaging (MRI). Methods and Results: Twenty consecutive patients undergoing a PV isolation procedure underwent selective PV angiography using a deflectable 8-French lumened catheter (Naviport, Cardima). The left superior PV (LSPV) runs upward and away from the spine in the right anterior oblique (RAO) projection and upward and toward the spine in the left anterior oblique (LAO) projection. The opposite is true for the right superior PV (RSPV). The left inferior PV (LIPV) has a bull's-eye appearance in the RAO projection, and the right inferior PV (RIPV) has a bull's-eye appearance in the LAO projection due to their end-on trajectories. The LIPV in the LAO projection and the RIPV in the RAO projection run horizontally toward the spine. An excellent correlation was noted in PV ostial size as assessed by angiography and MRI (r2 〈 0.90, P 〈 0.0001). Conclusion: This study describes the technique and results of PV angiography and fluoroscopy. The study also demonstrates good correlation of PV ostial diameters by contrast venography and MRI. PV angiography can be used as an alternate to MRI or computed tomographic imaging, particularly when these tests are unavailable or are contraindicated in the patient. (J Cardiovasc Electrophysiol, Vol. 15, pp. 21-26, January 2004)

Notes: SHUKLA, H.H., et al. : High Defibrillation Thresholds in Transvenous Biphasic Implantable Defibrillators: Clinical Predictors and Prognostic Implications. The aim of this study was to identify clinical characteristics that distinguish patients with high DFTs and assess the prognostic implication. DFTs testing is a lengthy, potentially painful, and a hazardous process. Little information is available concerning the identification of patients with high DFT who undergo ICD surgery with transvenous leads and biphasic energy. This study analyzed 968 patients from two separate clinical studies who received a Medtronic cardioverter defibrillator from January 1995 through November 1999 and who had DFT testing measured by a binary search protocol. Compared to 865 patients with low defibrillation thresholds (〈18 J), the 103 patients with high thresholds (≥18 J) had a lower LVEF (34 ± 16.7 vs 38.3 ± 16.2%, P = 0.01) , a worse NYHA functional class (23% Class I, 43% Class II, 29% Class III, 5% Class IV vs. 27% Class I, 55% Class II, 17% Class III, 1% Class IV, P 〈 0.0001), had bypass surgery less often (10.7 vs 27.5%,P 〈 0.0001), used amiodarone within the past 6 weeks(42.7 vs 27.2%, P = 0.002), and had a history of ventricular fibrillation more often(44.7 vs 33.1%, P = 0.02). Information concerning the number of shocks delivered was available in 345 (35%) patients; 23 were in the high DFT group and 322 were in the low DFT group. Twelve (52%) of the 23 patients in the high DFT arm received3.6 ± 2.7shocks (median 2.5) and 106 (33%) of the 322 patients with low DFT received4.9 ± 9.5shocks (median 2). After 6 months the mortality rate of patients with high thresholds was 11.7 vs 7.8% in patients with low thresholds(P = 0.118). Using a multivariate logistic regression model the significant predictors of death were older age, higher NYHA class, lower LVEF, amiodarone use, had a presenting arrhythmia of ventricular fibrillation and CHF but not initial high defibrillation thresholds. The study found that (1) 11% of patients have high DFTs, (2) clinical characteristics that identify high defibrillation thresholds are NYHA Class III, IV, low ejection fraction, no previous history of bypass surgery, prior amiodarone use preoperatively, and presenting with ventricular fibrillation, and (3) while high DFTs were associated with a more ill patient population, there was no difference in survival in a 6-month follow-up. Patients with a predicted low DFTs may be eligible for abbreviated ICD testing while high risk patients require formal testing. (PACE 2003; 26[Pt. I]:44–48)