Search

Background Statins have important pleiotropic effects and have been shown to reduce vascular inflammation and the incidence of atrial fibrillation (AF) after cardiac surgery. The role of statins in patients with existing AF is poorly understood. We examined the effect of statins on recurrence of AF in patients after successful cardioversion. Methods Statin use and documented recurrence of AF after successful cardioversion were evaluated in 625 patients with new onset AF who were followed prospectively in the Canadian Registry of Atrial Fibrillation. Logistic regression was used to model the effect of statin use on the recurrence of AF at 1 year while adjusting for potential confounders including concurrent medications. Results In a predominantly male population (62%) with median age 63 years, 12.3% were on statins at baseline. Overall, 32.5% had documented recurrence of AF at 1 year; 23.4% in patients on statins compared to 33.8% in those not on statins ( P = .07). After adjustment for baseline differences and concomitant β-blocker use, statin use was associated with a 74% reduction in AF recurrence, but only in statin users on β-blockers (OR 0.26, 95% CI 0.10-0.66); statin users not on β-blockers (OR 1.07, 95% CI 0.44-2.58). Conclusions In an observational study of patients with new onset AF, statin use was associated with a significant 74% reduction in the odds of recurrent AF, but only in patients also taking β-blockers. Importantly, statin without concomitant β-blocker use was not associated with any changes in AF recurrence.

Azimilide dihydrochloride (azimilide) is an investigational antiarrhythmic drug that has been tested in patients with a variety of arrhythmias. In patients with atrial fibrillation, it has shown excellent efficacy in some previous trials and minimal efficacy in others.Patients who had symptomatic atrial fibrillation for48 hours but6 months were eligible for this multicenter, randomized, placebo-controlled clinical trial. Patients were admitted to a hospital and randomly assigned to receive either azimilide 125 mg or a matched placebo twice daily for 3 days and then once daily. Patients who were in sinus rhythm spontaneously or had sinus rhythm restored by electric cardioversion on day 4 were discharged from the hospital. Recurrence of atrial fibrillation was documented by electrocardiogram. In the primary efficacy analysis, time to recurrence in the 2 treatment groups was compared with the log-rank test in the subgroup of patients with structural heart disease. Safety was assessed as deaths, adverse events, and serious adverse events.A total of 446 patients were randomized in the study; 314 were in the subgroup with structural heart disease. The median time to arrhythmia recurrence in both treatment groups with structural heart disease was 13 days, and the difference between treatments was not significant (P = .4596, n = 314). The relative risk for recurrence (placebo:azimilide) was 1.104 (95% CI 0.849-1.436). There was 1 death in the placebo group and 3 in the azimilide group.Azimilide did not demonstrate clinically important or statistically significant efficacy in reducing the risk for arrhythmia recurrence in patients with structural heart disease who were in atrial fibrillation and converted to sinus rhythm.

The effect of left atrial (LA) dimension on the recurrence of atrial fibrillation (AF) has been examined in small studies. We evaluated the effect of LA dimension on the occurrence of AF using 2- and 4-year echocardiographic data in a large cohort of patients with new onset AF.The Canadian Registry of AF (CARAF) enrolled subjects with AF at the first electrocardiographically confirmed diagnosis. Patients were classified at 2 and 4 years as no recurrent AF (No RAF), paroxysmal AF (PAF), or chronic AF (CAF) based on clinical symptoms and electrocardiographic documentation. The association between baseline, 2-, and 4-year LA dimensions with occurrence of AF as determined by echocardiography was evaluated using a multivariate analysis.The No RAF group (n = 176) had a significantly smaller LA dimension (36.9 +/- 6.8 mm) at baseline compared to the CAF group (n = 227) (42.8 +/- 7.5 mm, P.0001). The No RAF and PAF (n = 153) groups did not have a significant change in LA dimension at 2 or 4 years. Only those with CAF had a significant increase in LA dimension at 2 and 4 years, +1.39 mm (95% CI 0.01-2.8) and +3.48 mm (95% CI 1.8-5.2), respectively.A larger baseline LA dimension is associated with progression to CAF. Patients with no or paroxysmal recurrence had no change in LA dimension over a 4-year period. These findings have implications in tailoring modes of therapy in patients with AF.

Background After its initial diagnosis, atrial fibrillation (AF) may progress from paroxysmal to chronic AF (CAF). The rate of progression and risk factors for progression are not clearly defined. Methods The Canadian Registry of Atrial Fibrillation (CARAF) enrolled patients from 6 Canadian cities at the time of their first electrocardiographic diagnosis of AF. Comprehensive clinical and echocardiographic data were collected and patients were followed annually, carefully documenting clinical outcomes, recurrence of paroxysmal AF, and progression to CAF. Baseline clinical, electrocardiographic, and echocardiographic variables were evaluated by univariate Cox proportionate hazards analysis. A stepwise approach was used to model the association between echocardiographic and clinical variables with progression to CAF. Results A total of 757 patients with a baseline diagnosis of paroxysmal AF were evaluated. Median follow-up was 8.0 years (range 2 days to 11.1 years). The probability of progression to CAF by 1 year was 8.6% and thereafter there was a slow but steady progression to 24.7% by 5 years. By 5 years, the probability of documented recurrence of any AF (chronic or paroxysmal) was 63.2%. Increasing age, significant aortic stenosis or mitral regurgitation, left atrial enlargement, and diagnosis of cardiomyopathy were independently associated with progression to CAF. A more rapid heart rate during AF was associated with decreased risk of progression. Conclusions After the initial diagnosis of paroxysmal AF, there is a slow but steady progression to CAF. Baseline echocardiographic variables, age, cardiomyopathy, and heart rate were independently associated with progression to CAF.

Background Both “physiologic” (dual-chamber or atrial only) or ventricular-pacing-only permanent pacemakers provide chronotropic competence, with unknown health-related quality of life (QOL) differences between these options. The QOL studies within the Canadian Trial of Physiologic Pacing were performed to assess whether QOL differences exist in patients randomized to these 2 pacing modes. Methods Two QOL protocols were performed: 1) a substudy of 269 patients with detailed QOL measures (The Medical Outcomes Study, Short-Form [SF-36], the Pacemaker Syndrome Scale, an activity scale, and a pacemaker-specific scale) at baseline and 6 months after implantation; and 2) a parent study assessment of QOL in 1721 patients with a 12-item QOL instrument package (SF-6, “ladder of life,” and pacemaker syndrome scale) given 6 months after implantation only. Results In the substudy, pacing was associated with an average significant (P < .05) 0.36 SD unit improvement in QOL across all domains (SF-36: 38 ± 9 to 41 ± 11 for physical scores, 47 ± 11 to 52 ± 9 for mental health scores, both P < .001). Similar improvements were seen with the pacemaker-specific scales. There were no significant differences in the absolute or relative improvement in QOL between assigned pacing modes. The parent study similarly showed no differences in QOL between pacing modalities. Presyncope occurred in 31% of patients in the physiological pacing group, compared with 38% of the patients in the ventricular pacing group (P < .01). No other symptoms were different between the 2 groups. Pacemaker dependency, defined as an escape heart rate

Accelerated junctional rhythm following open heart surgery may lead to hemodynamic impairment due to loss of synchronized atrial contraction. Therefore, in this study we evaluated the frequency, duration, and hemodynamic effects of accelerated junctional rhythm in 30 patients undergoing coronary artery bypass (CAB) and in 30 undergoing valve replacement (VR). Accelerated junctional rhythm was defined as a rate greater than 55 bpm. Patients were continuously monitored postoperatively and rhythm strips obtained at least every 4 hours. Ten VR patients (33%) and four CAB patients (13%) exhibited accelerated junctional rhythm, the difference between these groups being significant (p less than 0.02). Nine of the 14 were hemodynamically compromised requiring inotropic support (9) and/or pacemaker insertion (2). The time of appearance of accelerated junctional rhythm ranged from immediate to 6 days (mean 26 +/- 52 hours, SD) and it lasted a mean of 16 +/- 22 hours. The rate ranged from 62 to 150 bpm. The sinus rate prior to the onset of accelerated junctional rhythm was significantly lower than the sinus rate in those not developing accelerated junctional rhythm. In conclusion, accelerated junctional rhythm is seen frequently following open heart surgery and may lead to hemodynamic deterioration. It is seen more frequently following VR, in approximately 33% of patients. Its manifestation appears to result from a combination of acceleration of junctional focus and slowing of sinus node discharge.