Mapping potentials adjacent to the cavo-tricuspid isthmus ablation line during incremental pacing: A feasible and highly accurate maneuver to confirm complete CTI conduction block.

BACKGROUND: The diagnostic accuracy of incremental atrial pacing (IP) to determine complete cavo-tricuspid isthmus (CTI) block during typical atrial flutter (AFL) ablation is limited by both an extensive/nonlinear ablation and/or the presence of intra-atrial conduction delay elsewhere in the right atrium. We examined the diagnostic performance of an IP variant based on the assessment of the atrial potentials adjacent to the ablation line which aims at overcoming both limitations. METHODS: From a prospective population of 108 consecutive patients, 15 were excluded due to observation of inconclusive CTI ablation potentials precluding for a straight comparison between the IP maneuver and its variant. In the remaining 93, IP was performed from the low lateral right atrium and the coronary sinus ostium, with the ablation catheter positioned both at the CTI line and adjacent (<5 mm) to its septal and lateral aspect. The IP variant consisted of measuring the interval between the two atrial electrograms situated on the same side of the ablation line, opposite to the pacing site, a ≤10 ms increase indicating complete CTI block. RESULTS: The IP maneuver and its variant were consistent with complete CTI block in 82/93 (88%) and 87/93 (93%) patients, respectively. Four patients had AFL recurrence during follow-up: 2/4 and 4/4 had been adequately classified as incomplete block by the IP maneuver and its variant, respectively. Twenty-three patients (24%) had significant intra-atrial conduction delay elsewhere in the right atrium. The IP maneuver and its variant were suggestive of an incomplete CTI block in 11/23 and 4/23 in this setting (P = .028), with the later best predicting subsequent AFL relapses (2/12 vs 2/4, P = .01). CONCLUSIONS: The IP variant, which was designed to overcome the limitations of the conventional IP maneuver, accurately distinguishes complete from incomplete CTI block and helps to predict AFL recurrences after ablation.

Long-term mortality predictors in patients with chronic bifascicular block.

AIMS: To evaluate the long-term mortality rate and to determine independent mortality risk factors in patients with bifascicular block (BFB). Patients with BFB are known to have a higher mortality risk than the general population, not only related to progression to atrio-ventricular block but also due to the presence of malignant ventricular arrhythmias. Previous observational and epidemiological studies including a high proportion of patients with structural heart disease have shown an important cardiac mortality rate and may not reflect the real outcome of patients with BFB. METHODS AND RESULTS: From March 1998 until December 2006, we prospectively studied 259 consecutive BFB patients, 213 (82%) of whom presenting with syncope/pre-syncope, undergoing electrophysiological study. After a median follow-up of 4.5 years (P25:2.16-P75:6.41), 53 patients (20.1%) died, 19 (7%) of whom due to cardiac aetiology. Independent total mortality predictors were age [hazard ratio (HR) 1.04, 95% confidence interval (CI) 1.01-1.09], NYHA class>or=II (HR 2.17, 95% CI 1.05-4.5), atrial fibrillation (HR 2.96, 95% CI 1.1-7.92), and renal dysfunction (HR 4.26, 95% CI 2.04-9.01). An NYHA class of >or=II (HR 5.45, 95% CI 2.01-14.82) and renal failure (HR 3.82, 95% CI 1.21-12.06) were independent predictors of cardiac mortality. No independent predictors of arrhythmic death were found. CONCLUSION: Total mortality, especially of cardiac cause, is lower than previously described in BFB patients. Advanced NYHA class and renal failure are predictors of cardiac mortality.

Double factor single shot to diminish complications in cryoballoon ablation procedures for atrial fibrillation.

PURPOSE: Cryoballoon ablation (CBA) has become a standard treatment for recurrent atrial fibrillation (AF). There is need for improved CBA protocols. We aimed to demonstrate that a new protocol including minimum temperature (minT) reached could reduce procedure times and complications. METHODS: A new double factor protocol (DFP), based on the performance of one single shot per vein with variable duration, and conditional bonus shot, determined by time-to-effect (TTE) and minT, was compared with the conventional protocol (CP), with at least two shots per vein. Procedure parameters, complications, and efficacy were compared. RESULTS: We prospectively included 88 consecutive patients treated with the DFP. These were compared to the previous consecutive 69 patients treated with CP. All procedures were performed with 28-mm second-generation balloon. Acute pulmonary vein (PV) isolation was similar (98.6% vs. 98.9% in CP vs. DFP, p = 0.687). Procedure and ablation times favored DFP over CP (120 vs. 134 min, p = 0.003; and 1051 vs. 1475 s, p < 0.001; respectively). A composite of major and minor complications was significantly reduced in the DFP compared to the CP (18.8% vs. 6.8%, p = 0.02; respectively). Within a follow-up of 18 months, freedom from AF was 79.7% in CP and 78.4% in DFP (Log-rank 0.501). Paroxysmal AF and absence of PV potentials predicted better arrhythmia outcomes (HR 2.14 for paroxysmal vs. persistent, p = 0.031; and HR 1.61 for absence vs. presence of PV potentials, p = 0.01). CONCLUSIONS: The novel DFP results in reduced complication rates and procedure times, with similar success rates compared with a conventional strategy.

Pulmonary hemorrhage after cryoballoon ablation for pulmonary vein isolation in the treatment of atrial fibrillation.

Pulmonary vein isolation has evolved over the past years as an alternative for the treatment of symptomatic recurrences of atrial fibrillation refractory to antiarrhythmic drug treatment. Both radiofrequency energy and cryoballoon ablation have proven useful in this setting. We present the case of a 55-year-old male patient undergoing cryoballoon ablation complicated with pulmonary hemorrhage. The cause of this rare complication may be found in the damage of vascular venous structures near the ablation zone or, alternatively, in hemorrhagic damage of the pulmonary vein surrounding tissue (or less probably to direct injury of the lingular bronchus). The extremely low temperatures achieved in this case (which are often associated with deep balloon position inside the veins) are alarming and should alert the physician about the possibility of an excessively intrapulmonary vein deployment of the cryoablation balloon.

Incremental His-to-coronary sinus maneuver: a nonlocal electrogram-based technique to assess complete cavotricuspid isthmus block during typical flutter ablation.

BACKGROUND: Achievement of complete cavotricuspid isthmus (CTI) conduction block reduces typical atrial flutter recurrences after ablation. The lack of increase in the His-to-coronary sinus ostium atrial interval during incremental pacing (IP) from the low lateral right atrium may distinguish slow conduction from complete CTI conduction block. METHODS AND RESULTS: Sixty-six consecutive patients (age, 65±13 years; 18% female) were prospectively included. A <10 ms increase in the His-to-coronary sinus ostium atrial timing during low lateral right atrium IP at cycle length of 600 ms through 300 ms was compared with the previously reported IP maneuver for the confirmation of complete CTI block. On the basis of the IP maneuver, complete CTI block (phase 2) was achieved in 59 patients, in 13 of whom an intermediate phase of functional CTI block (phase 1) was observed. In the remaining 7 patients, the IP maneuver did not allow for assessment of complete CTI block because of the presence of inconclusive potentials in the CTI ablation line. As compared with the IP maneuver, the incremental His-to-coronary sinus ostium maneuver was consistent with functional CTI block during phase 1 in all cases and conclusive of complete CTI block in 98% of cases during phase 2. CONCLUSIONS: The incremental His-to-coronary sinus ostium maneuver is analogous to the IP maneuver in distinguishing complete CTI block from persistent CTI conduction. This maneuver may provide confirmation of CTI block in those patients in whom assessment of local electrogram-based criteria is not feasible because of inconclusive potentials in the CTI ablation line.

[Novel predictors of progression of atrioventricular block in patients with chronic bifascicular block]. / Nuevos predictores de evolución a bloqueo auriculoventricular en pacientes con bloqueo bifascicular.

INTRODUCTION AND OBJECTIVES: Patients with chronic bifascicular block (BFB) can progress to advanced atrioventricular block (AVB), especially when syncope or a prolonged HV interval is present. It is possible that other variables could help identify patients who would benefit from prophylactic pacemaker implantation. METHODS: The study involved 263 consecutive BFB patients seen at a single center between 1998 and 2006. Clinical, electrocardiographic and electrophysiologic variables were analyzed to identify predictors of progression to significant AVB (i.e. second or third grade). Cardiac pacemakers were implanted in accordance with European Society of Cardiology guidelines. Pacemakers were programmed in the VVI mode with a minimum frequency of 40 beats/min. A pacemaker was required if there was significant AVB or a ventricular pacing percentage >10%. RESULTS: In total, the study included 249 patients (mean age, 73.4+/-9.3 years, 82 female). After a median follow-up period of 4.5 years (2.16-6.41 years), a pacemaker was required by 102 patients: 45 had a ventricular pacing percentage >10% and 57 had significant AVB. Factors predictive of the need for a pacemaker were: the presence of syncope or presyncope (hazard ratio [HR]=2.06; 95% confidence interval [CI], 1.03-4.12), QRS width >140 ms (HR=2.44; 95% CI, 1.59-3.76), renal failure (HR=1.86; 95% CI, 1.22-2.83), and an HV interval >64 ms (HR=6.6; 95% CI, 4.04-10.80). The presence of all four risk factors was associated with a 95% probability of needing a pacemaker within 1 year of follow-up. CONCLUSIONS: The presence of syncope or presyncope, a QRS width >140 ms, renal failure, and an HV interval >64 ms were independent predictors of progression to AVB in patients with BFB.