Atrial pacing minimization in sinus node dysfunction and risk of incident atrial fibrillation: a randomized trial.

BACKGROUND AND AIMS: High percentages of atrial pacing have been associated with an increased risk of atrial fibrillation. This study is aimed at evaluating whether atrial pacing minimization in patients with sinus node dysfunction reduces the incidence of atrial fibrillation. METHODS: In a nationwide, randomized controlled trial, 540 patients with sinus node dysfunction and an indication for first pacemaker implantation were assigned to pacing programmed to a base rate of 60 bpm and rate-adaptive pacing (DDDR-60) or pacing programmed to a base rate of 40 bpm without rate-adaptive pacing (DDD-40). Patients were followed on remote monitoring for 2 years. The primary endpoint was time to first episode of atrial fibrillation longer than 6 min. Secondary endpoints included longer episodes of atrial fibrillation, and the safety endpoint comprised a composite of syncope or presyncope. RESULTS: The median percentage of atrial pacing was 1% in patients assigned to DDD-40 and 49% in patients assigned to DDDR-60. The primary endpoint occurred in 124 patients (46%) in each treatment group (hazard ratio [HR] 0.97, 95% confidence interval [CI] 0.76-1.25, P = .83). There were no between-group differences in atrial fibrillation exceeding 6 or 24 h, persistent atrial fibrillation, or cardioversions for atrial fibrillation. The incidence of syncope or presyncope was higher in patients assigned to DDD-40 (HR 1.71, 95% CI 1.13-2.59, P = .01). CONCLUSIONS: Atrial pacing minimization in patients with sinus node dysfunction does not reduce the incidence of atrial fibrillation. Programming a base rate of 40 bpm without rate-adaptive pacing is associated with an increased risk of syncope or presyncope.

Risk profile, antithrombotic treatment and clinical outcomes of patients in Nordic countries with atrial fibrillation - results from the GARFIELD-AF registry.

AIMS: The objective was to evaluate the clinical characteristics, management and two-year outcomes of patients with newly diagnosed non-valvular atrial fibrillation at risk for stroke in Nordic countries. METHODS: We examined the baseline characteristics, antithrombotic treatment, and two-year clinical outcomes of patients from four Nordic countries. RESULTS: A total of 52,080 patients were enrolled in the GARFIELD-AF. Out of 29,908 European patients, 2,396 were recruited from Nordic countries. The use of oral anticoagulants, alone or in combination with antiplatelet (AP), was higher in Nordic patients in all CHA2DS2-VASc categories: 0-1 (72.8% vs 60.3%), 2-3 (78.7% vs 72.9%) and ≥4 (79.2% vs 74.1%). In Nordic patients, NOAC ± AP was more frequently prescribed (32.0% vs 27.7%) and AP monotherapy was less often prescribed (10.4% vs 18.2%) when compared with Non-Nordic European patients. The rates (per 100 patient years) of all-cause mortality and non-haemorrhagic stroke/systemic embolism (SE) were similar in Nordic and Non-Nordic European patients [3.63 (3.11-4.23) vs 4.08 (3.91-4.26), p value = .147] and [0.98 (0.73-1.32) vs 1.02 (0.93-1.11), p value = .819], while major bleeding was significantly higher [1.66 (1.32-2.09) vs 1.01 (0.93-1.10), p value < .001]. CONCLUSION: Nordic patients had significantly higher major bleeding than Non-Nordic-European patients. In contrast, rates of all-cause mortality and non-haemorrhagic stroke/SE were comparable. CLINICAL TRIAL REGISTRATION: Unique identifier: NCT01090362. URL: http://www.clinicaltrials.gov. KEY MESSAGE: Nordic countries had significantly higher major bleeding than Non-Nordic-European countries. Rates of mortality and non-haemorrhagic stroke/SE were similar .

QT interval dynamics predict mortality in high-risk patients after myocardial infarction.

OBJECTIVE: The purpose of this study was to evaluate the prognostic properties of the QT/RR relationship in survivors of myocardial infarction with severe left ventricular dysfunction. DESIGN: The QT/RR interval slope was assessed from 24-h electrocardiographic recordings obtained from 241 patients representative of survivors of an acute myocardial infarction with an ejection fraction < or =35%. During a median follow-up of 752 days, 63 patients died. RESULTS: In a multivariate analysis QT/RR at night-time was an independent predictor of all-cause mortality. A linear all-cause mortality predictor score was calculated from age, ejection fraction, QRS duration and QT/RR night, allowing identification of a high-risk one-third of the patients with a relative risk of death at 4.0. CONCLUSION: This study demonstrates independent prognostic information of night-time QT/RR dynamics in patients at high risk after myocardial infarction. A linear predictor score calculated from age, ejection fraction, QRS duration and QT/RR night identifies a high-risk one-third of the patients with a 1-year mortality of 36% vs 9% in the remaining patients.