Nikola Drca

Alcohol consumption and risk of atrial fibrillation: a prospective study and dose-response meta-analysis.

BACKGROUND Although high alcohol consumption has been associated with increased risk of atrial fibrillation (AF), the role of light to moderate drinking remains unclear. OBJECTIVES The study sought to investigate the association between alcohol consumption and AF risk in a prospective study of Swedish men and women and to conduct a meta-analysis of prospective studies to summarize available evidence. METHODS We followed 79,019 men and women who, at baseline, were free from AF and had completed a questionnaire about alcohol consumption and other risk factors for chronic diseases. Incident AF cases were ascertained by linkage to the Swedish Inpatient Register. For the meta-analysis, studies were identified by searching PubMed through January 10, 2014, and by reviewing references of pertinent publications. Study-specific relative risks (RRs) were combined using a random effects model. RESULTS Over 859,420 person-years of follow-up (1998 to 2009), 7,245 incident AF cases were identified in our own cohort study. The association between alcohol consumption and AF did not differ by sex (p for interaction = 0.74). Compared with current drinkers of <1 drink/week (12 g alcohol/drink), the multivariable RRs of AF were 1.01 (95% confidence interval [CI]: 0.94 to 1.09) for 1 to 6 drinks/week, 1.07 (95% CI: 0.98 to 1.17) for 7 to 14 drinks/week, 1.14 (95% CI: 1.01 to 1.28) for 15 to 21 drinks/week, and 1.39 (95% CI: 1.22 to 1.58) for >21 drinks/week. Results were similar after excluding binge drinkers. In a meta-analysis of 7 prospective studies, including 12,554 AF cases, the RRs were 1.08 (95% CI: 1.06 to 1.10) for 1 drink/day, 1.17 (95% CI: 1.13 to 1.21) for 2 drinks/day, 1.26 (95% CI: 1.19 to 1.33) for 3 drinks/day, 1.36 (95% CI: 1.27 to 1.46) for 4 drinks/day, and 1.47 (95% CI: 1.34 to 1.61) for 5 drinks/day, compared with nondrinkers. CONCLUSIONS These findings indicate that alcohol consumption, even at moderate intakes, is a risk factor for atrial fibrillation.

Atrial fibrillation is associated with different levels of physical activity levels at different ages in men

Objective This study examines the influence of physical activity at different ages and of different types, on the risk of developing atrial fibrillation (AF) in a large cohort of Swedish men. Methods Information about physical activity was obtained from 44 410 AF-free men, aged 45–79 years (mean age=60), who had completed a self-administered questionnaire at baseline in 1997. Participants reported retrospectively their time spent on leisure-time exercise and on walking or bicycling throughout their lifetime (at 15, 30 and 50 years of age, and at baseline (mean age=60)). Participants were followed-up in the Swedish National Inpatient Register for ascertainment of AF. Cox proportional hazards regression models were used to estimate relative risks (RR) with 95% CIs, adjusted for potential confounders. Results During a median follow-up of 12 years, 4568 cases of AF were diagnosed. We observed a RR of 1.19 (95% CI 1.05 to 1.36) of developing AF in men who at the age of 30 years had exercised for >5 h/week compared with <1 h/week. The risk was even higher (RR 1.49, 95% CI 1.14 to 1.95) among the men who exercised >5 h/week at age 30 and quit exercising later in life (<1 h/week at baseline). Walking/bicycling at baseline was inversely associated with risk of AF (RR 0.87, 95% CI 0.77 to 0.97 for >1 h/day vs almost never) and the association was similar after excluding men with previous coronary heart disease or heart failure at baseline (corresponding RR 0.88, 95% CI 0.77 to 0.998). Conclusions Leisure-time exercise at younger age is associated with an increased risk of AF, whereas walking/bicycling at older age is associated with a decreased risk.

Physical activity is associated with a reduced risk of atrial fibrillation in middle-aged and elderly women

Objective Previous studies have found that regular participation in intense physical activity increases the risk of developing atrial fibrillation (AF) in men, but it remains unclear how physical activity influences the risk of AF in women. We aimed to examine whether physical activity of different types and at different ages influences the development of AF in women. Methods In the population-based Swedish Mammography Cohort, information about physical activity was obtained from 36 513 AF-free women (49–83 years old, median age 60 years) who had completed a questionnaire at study entry (1997). Participants reported their time spent on leisure-time exercise and on walking or bicycling throughout their lifetime (at study entry, and at 30 and 50 years of age). We used the Swedish National Inpatient Register (IPR) to determine whether the participants were diagnosed with AF. Cox proportional hazards regression models were used to estimate relative risks (RR) with 95% CI, adjusted for potential confounders. Results During a median follow-up of 12 years (10th percentile 7.5 years, 90th percentile 12.0 years), 2915 cases of AF were diagnosed. The risk of AF decreased with increasing levels of leisure-time exercise at study entry (RR 0.85, 95% CI 0.75 to 0.95 for ≥4 h/week vs <1 h/week) and walking/bicycling (RR 0.81, 95% CI 0.72 to 0.92, for ≥40 min/day vs almost never). Conclusions Physical activity is associated with a reduced risk of AF in women. Moderate amount of physical activity was sufficient to significantly reduce AF risk.

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.

Combined impact of healthy lifestyle factors on risk of atrial fibrillation: Prospective study in men and women

BACKGROUND The combined impact of multiple lifestyle factors on risk of atrial fibrillation (AF) remains unclear. We investigated the joint association of four modifiable lifestyle factors on incidence of AF in a prospective study of men and women. METHODS The study cohort comprised 39 300 men in the Cohort of Swedish Men and 33 090 women in the Swedish Mammography Cohort who were 45-83 years of age and free from atrial fibrillation at baseline. Healthy lifestyle was defined as body mass index <25 kg/m(2), regular exercise for ≥ 20 min/day, no or light-to-moderate alcohol consumption (≤ 2 drinks/day for men and ≤ 1 drink/day for women), and not smoking. Incident AF cases were identified through linkage with the Swedish National Inpatient Register. RESULTS During a mean follow-up of 10.9 years, AF occurred in 4028 men and 2539 women. Compared with men and women with no healthy lifestyle factors, the multivariable relative risks (95% confidence interval) of AF were 0.83 (0.65-1.07) for one, 0.74 (0.58-0.94) for two, 0.62 (0.49-0.79) for three, and 0.50 (0.39-0.64) for four healthy lifestyle factors (P for trend <0.0001). The inverse association was similar in men and women. CONCLUSIONS Four healthy lifestyle factors combined were associated with a halving of the risk of AF.

Cryoablation of substrates adjacent to the atrioventricular node: acute and long-term safety of 1303 ablation procedures

AIMS Radiofrequency (RF) ablation is effective for ablation of atrial arrhythmias. However, RF ablation in the vicinity of the atrioventricular (AV) node is associated with a risk of inadvertent, irreversible high-grade AV block, depending on the type of substrate. Cryoablation is an alternative method. The objective was to investigate the acute and long-term risks of AV block during cryoablation. METHODS AND RESULTS We studied 1303 consecutive cryoablations of substrates in the vicinity of the AV node in 1201 patients (median age 51 years, range 6-89 years) on acute and long-term impairment to the AV nodal conduction system. The arrhythmias treated were AV nodal reentrant tachycardias (n=1116), paraseptal and superoparaseptal accessory pathways (n=100), and focal atrial tachycardias (n=87). In 158 (12%) procedures, cryomapping (38 cases) or cryoablation (120 cases) were stopped due to transient AV block (first-degree AV block 74 cases, second-degree AV block 67 cases, and third-degree AV block 17 cases) after which another site was tested. Transient AV block occurred within seconds of mapping up to 3 min of ablation. The incidence of AV block was similar for different substrates. In most cases, AV nodal conduction was restored within seconds but in two cases transient AV block lasted 21 and 45 min, respectively. There were no cases of acute permanent AV blocks. No late AV blocks occurred during follow-up (mean 24 months, range 6-96 months). CONCLUSION Cryoablation adjacent to the AV node carries a negligible risk of permanent AV block. Transient AV block during ablation is a benign finding.

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.

Incidence of atrial fibrillation in relation to birth weight and preterm birth

BACKGROUND Hypertension, type 2 diabetes and other cardiovascular diseases, all risk factors for atrial fibrillation, are associated with birth weight. It remains unclear, however, whether risk of atrial fibrillation is also associated with birth weight. We investigated the associations of birth weight and preterm birth (i.e., born more than one month before term) with risk of atrial fibrillation (AF). METHODS The study population comprised 29551 men and 23454 women who were free from AF at baseline. Information on birth weight, preterm birth, and risk factors for AF was obtained from a questionnaire. Incident AF cases were ascertained by linkage to the Swedish Inpatient Register. RESULTS During 12years of follow-up, AF developed in 2711 men and 1491 women. High birth weight (≥5000g) was associated with an increased risk of AF after adjustment for age and other risk factors for AF, but the association did not persist after further adjustment for adult height. In men but not in women, low birth weight was associated with an increased risk of AF. Compared with men weighing 2500-3999g at birth, the multivariable RR was 1.86 (95% CI, 1.15 to 3.00) for those weighing <1500g. This association was stronger in men who were born full-term (RR 2.53; 95% CI, 1.35 to 4.73). CONCLUSIONS Both high birth weight and low birth weight (in men), in particular in men born full-term, were associated with an increased risk of AF. The association with high birth weight appeared to be mediated through adult height.

Cryoablation of atrioventricular nodal re-entrant tachycardia: 7-year follow-up in 515 patients—confirmed safety but very late recurrences occur

Aims Cryoablation is an alternative method to radiofrequency ablation for treatment of atrioventricular nodal re-entrant tachycardia (AVNRT). This study investigates the long-term safety and efficacy of cryoablation in AVNRT. Methods and results We studied 515 consecutive patients (317 women, mean age 50 years, range 13-89 years) undergoing a first cryoablation for AVNRT between 2003 and 2008. Ablations were performed with a 6-mm Freezor Xtra catheter. Six patients were acute failures; 494 out of 509 (97%) primarily successfully ablated patients were followed up for a mean of 7.1 years (range 2-12 years). About 11% (54/494 patients) of patients had recurrences of the index arrhythmia. Time to recurrence varied from days to 9 years; 14 patients (3%) had recurrences later than 2 years, 8 patients (2%) later than 3 years, and 6 patients (2%) later than 4 years. Recurrence rate was higher in patients with slow-slow or fast-slow AVNRT (n = 24) compared with the common slow-fast variant (25 vs. 10%; P = 0.04). Recurrence rate was not higher in patients with residual slow pathway conduction (jump with or without echo beat, n = 199, 39%). Transient atrioventricular (AV) block of the first-, second-, or third-degree during ablation was observed in 45 patients but had no impact on the risk of AVNRT recurrence. No late AV block occurred. Single vs. multiple applications or total amount of cryoenergy delivered did not differ between patients with and without recurrences. Conclusion Cryoablation in AVNRT is safe with a long-term efficacy of 88%; however, very late recurrences occur.