Fariborz Tabrizi

Comorbidity and Myocardial Dysfunction Are the Main Explanations for the Higher 1-Year Mortality in Acute Myocardial Infarction With Left Bundle-Branch Block

Background—The purpose of this study was to assess the independent contribution of left bundle-branch block (LBBB) on cause-specific 1-year mortality in a large cohort with acute myocardial infarction (MI). Methods and Results—We studied a prospective cohort of 88 026 cases of MI from the Register of Information and Knowledge about Swedish Heart Intensive care Admissions in 72 hospitals in 1995 to 2001. Long-term mortality was calculated by Cox regression analysis, adjusted for multiple covariates that affect mortality by calculation of a propensity score. LBBB was present in 9% (8041 of 88 026) of the MI admissions. Patients with LBBB were older and had a higher prevalence of comorbid conditions than patients with no LBBB. The unadjusted relative risk of death within 1 year was 2.16 (95% CI, 2.08 to 2.24; P<0.001) for LBBB (42%, 3350 of 8041) compared with those with no LBBB (22%, 17 044 of 79 011). After adjustment for a propensity score that takes into account differences in risk factors and acute intervention, LBBB was associated with a relative risk of death of 1.19 (95% CI, 1.14 to 1.24; P<0.001). In a subgroup of 11 812 patients for whom left ventricular ejection fraction was available and could be added to the analysis, the contributing relative risk of LBBB for death was only 1.08 (95% CI, 0.93 to 1.25; P=0.33). The most common cause of death in both groups was ischemic heart disease. Conclusions—MI patients with LBBB have more comorbid conditions and an increased unadjusted 1-year mortality. When adjusted for age, baseline characteristics, concomitant diseases, and left ventricular ejection fraction, LBBB does not appear to be an important independent predictor of 1-year mortality in MI.

Acute and long-term outcome of cryoablation therapy of typical atrioventricular nodal reentrant tachycardia

AIMS The purpose of this study was to evaluate the safety and efficacy of cryoablation in a large series of patients with typical (slow-fast) atrioventricular nodal reentrant tachycardia (AVNRT). METHODS AND RESULTS Between 2003 and 2007, 312 patients with typical AVNRT--median age of 53 years (range 10-92), 200 women (64%)--underwent cryoablation, using exclusively a 6 mm tip catheter tip. Acute success was achieved in 309 of 312 patients (99%). The overall recurrence rate was 18 of 309 (5.8%) during a mean follow-up of 673 +/- 381 days. Sixteen of these patients (89%) were successfully reablated. The recurrence rate was 9% in patients with residual dual atrioventricular (AV) nodal pathway post-ablation compared with 4% in those with complete elimination of slow pathway conduction (P = 0.05). No patient developed permanent AV block. CONCLUSION Cryoablation of AVNRT can be achieved with a high acute success rate and a reasonable recurrence rate at long-term follow-up. Complete abolition of slow pathway conduction seems to predict better late outcome.

High success rate with cryomapping and cryoablation of atrioventricular nodal reentrytachycardia.

Introduction: Cryoablation is a new alternative to radiofrequency (RF) ablation for treatment of atrioventricular nodal reentry tachycardias (AVNRT). Mapping with reversible effect on the arrhythmia substrate or the AV node can be done before irreversible ablation is performed. This study evaluates an approach with systematic cryomapping, ablating only in areas with prompt effect on the arrhythmia substrate and evaluates whether the success rates and procedure times are similar to RF ablation.

Cryoablation of superoparaseptal and septal accessory pathways: a single centre experience

AIMS Radiofrequency (RF) catheter ablation in the septum close to the atrioventricular (AV) node or His bundle has an increased risk of irreversible complications. Cryothermal energy has the advantages of reversible cryomapping and increased catheter stability. This study evaluates the usefulness of cryoablation in superoparaseptal and septal accessory pathways (APs). METHODS AND RESULTS Twenty-seven consecutive patients (16 men, 11 women, median age 29 years, range 15-65) underwent cryoablation for APs either located in the superoparaseptal (n=18) or septal (n=9) area. Cryomapping, using exclusively a 6 mm tip catheter, at -30 degrees C was performed before ablation with a goal temperature of -80 degrees C for 240 s. Acute success was achieved in 26 out of 27 patients (96%). Total procedure and fluoroscopy time was 163+/-61 and 30+/-22 min, respectively. During a follow-up for a mean of 996+/-511 days, seven patients (27%) had recurrences of arrhythmia. Five out of these seven underwent a second cryoablation with successful results, giving a total success rate of 89%. Two patients developed transient second degree AV block during cryoablation; however, no permanent AV block was observed. The recurrence rate was significantly higher in patients with procedure-related transient mechanical AP block (6/7; 86%) due to catheter trauma compared with those without mechanical block (5/20; 25%; P=0.006). CONCLUSION Cryoablation of the superoparaseptal and septal APs is a safe and effective alternative to RF therapy. Procedure-related transient mechanical AP block predicts worse late outcome.

Safety and efficacy of cryoablation of atrial tachycardia with high risk of ablation-related injuries

AIMS The purpose of this study was to evaluate the safety and efficacy of cryoablation as an alternative to radio frequency (RF) ablation in high-risk-located atrial tachycardia (AT). METHODS AND RESULTS Between 2004 and 2007, 164 patients underwent catheter ablation due to AT at our institution. Twenty-six of these patients (22 women and 4 men), median age 58 years (range 14-76), were considered having high-risk-located AT and were treated by cryoablation. Seven patients had failed prior RF ablation due to high risk of complications. The AT foci distribution was: close to the AV node (n = 14), vicinity of the sinus node (n = 7), and crista terminalis adjacent to the phrenic nerve (n = 5). Cryomapping, using a 6 mm tip catheter, at -30 degrees C was performed before ablation with a goal temperature of -80 degrees C for 240 s. Acute success rate was achieved in 25/26 patients (96%). During a follow-up of 493 +/- 258 days, three patients had recurrences. Two of these underwent a second successful cryoablation procedure. Long-term success rate was 92%. Phrenic nerve palsy occurred in two patients with complete recovery after 1 day and 5 months, respectively. CONCLUSION Cryoablation of high-risk-located AT foci is a safe and effective alternative to RF therapy.

Cryoballoon ablation: a novel technique for treating focal atrial tachycardias from the pulmonary veins.

AIMS Cryothermic ablation using a cryoballoon is a novel technique which has been used to treat paroxysmal atrial fibrillation. In this study, we wanted to test this technique to treat focal atrial tachycardias (ATs) from the pulmonary veins (PV). METHODS AND RESULTS Five patients (four women, one man, mean age 43 +/- 16 years) with severe symptoms due to focal AT originating from a PV were studied. A single transseptal puncture was done. After confirmation of the diagnosis by conventional mapping, a 23 or 28 mm cryoballoon catheter was positioned in the PV of interest. Freezing was done for 300 s and repeated at least once before attempts to induce arrhythmia. All patients were successfully treated. Total procedure and fluoroscopy time was 138 +/- 55 and 26 +/- 21 min, respectively. During a follow-up of 10 +/- 7 months no clinical recurrences occurred. CONCLUSION Cryoablation using a cryoballoon might be an easy and safe tool to treat ATs originating from the PV with reasonable procedure time.