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.

Wolff-Parkinson-White in patient with permanent AFLI.

A 63-year-old mand with permanent atrial fibrillation through five years presents to the emergency room with dyspnea and an ECG showing pre-excited afib. The ECG was initially perceived as afib with bundle branch block and treated with digoxin. After that, treatment with amiodaron was given; also without success. After DC-conversion, multiple times and relapse, the patient was transferred to a highly specialised hospital, and an accessory pathway was performed ablated. This is a case report of a patient who had permanent atrial fibrillation and whose initial presentation of Wolff-Parkinson White syndrome was pre-excited atrial fibrillation.

Anterior-Lateral Versus Anterior-Posterior Electrode Position for Cardioverting Atrial Fibrillation.

BACKGROUND: Smaller randomized studies have reported conflicting results regarding the optimal electrode position for cardioverting atrial fibrillation. However, anterior-posterior electrode positioning is widely used as a standard and believed to be superior to anterior-lateral electrode positioning. Therefore, we aimed to compare anterior-lateral and anterior-posterior electrode positioning for cardioverting atrial fibrillation in a multicenter randomized trial. METHODS: In this multicenter, investigator-initiated, open-label trial, we randomly assigned patients with atrial fibrillation scheduled for elective cardioversion to either anterior-lateral or anterior-posterior electrode positioning. The primary outcome was the proportion of patients in sinus rhythm after the first shock. The secondary outcome was the proportion of patients in sinus rhythm after up to 4 shocks escalating to maximum energy. Safety outcomes were any cases of arrhythmia during or after cardioversion, skin redness, and patient-reported periprocedural pain. RESULTS: We randomized 468 patients. The primary outcome occurred in 126 patients (54%) assigned to the anterior-lateral electrode position and in 77 patients (33%) assigned to the anterior-posterior electrode position (risk difference, 22 percentage points [95% CI, 13-30]; P<0.001). The number of patients in sinus rhythm after the final cardioversion shock was 216 (93%) assigned to anterior-lateral electrode positioning and 200 (85%) assigned to anterior-posterior electrode positioning (risk difference, 7 percentage points [95% CI, 2-12]). There were no significant differences between groups in any safety outcomes. CONCLUSIONS: Anterior-lateral electrode positioning was more effective than anterior-posterior electrode positioning for biphasic cardioversion of atrial fibrillation. There were no significant differences in any safety outcome. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03817372.

Role for machine learning in sex-specific prediction of successful electrical cardioversion in atrial fibrillation?

OBJECTIVE: Electrical cardioversion is frequently performed to restore sinus rhythm in patients with persistent atrial fibrillation (AF). However, AF recurs in many patients and identifying the patients who benefit from electrical cardioversion is difficult. The objective was to develop sex-specific prediction models for successful electrical cardioversion and assess the potential of machine learning methods in comparison with traditional logistic regression. METHODS: In a retrospective cohort study, we examined several candidate predictors, including comorbidities, biochemistry, echocardiographic data, and medication. The outcome was successful cardioversion, defined as normal sinus rhythm immediately after the electrical cardioversion and no documented recurrence of AF within 3 months after. We used random forest and logistic regression models for sex-specific prediction. RESULTS: The cohort comprised 332 female and 790 male patients with persistent AF who underwent electrical cardioversion. Cardioversion was successful in 44.9% of the women and 49.9% of the men. The prediction errors of the models were high for both women (41.0% for machine learning and 48.8% for logistic regression) and men (46.0% for machine learning and 44.8% for logistic regression). Discrimination was modest for both machine learning (0.59 for women and 0.56 for men) and logistic regression models (0.60 for women and 0.59 for men), although the models were well calibrated. CONCLUSIONS: Sex-specific machine learning and logistic regression models showed modest predictive performance for successful electrical cardioversion. Identifying patients who will benefit from cardioversion remains challenging in clinical practice. The high recurrence rate calls for thoroughly informed shared decision-making for electrical cardioversion.

Cardioversion of atrial fibrillation in a real-world setting: non-vitamin K antagonist oral anticoagulants ensure a fast and safe strategy compared to warfarin.

Aims: Non-vitamin K antagonist oral anticoagulants (NOACs) are increasingly used as thromboembolic prophylaxis in cardioversion. We examined the waiting time to cardioversion and the outcomes in patients with non-valvular atrial fibrillation (AF) of > 48 h of duration who were treated with either NOACs or warfarin. Methods and results: Anticoagulation was handled in a structured, multidisciplinary AF-clinic. The objectives were the waiting time to cardioversion, and thromboembolism and major bleeding events within 60 days. In total, 2150 electrical cardioversions were performed; 684 (31.8%) of patients were on NOACs and 1466 (68.2%) were on warfarin. The waiting time to non-TOE-guided cardioversion was significantly shorter in the NOAC group compared with the warfarin group for all cardioversions (P < 0.001 for log-rank test) and for first-time cardioversions (P < 0.001 for log-rank test). For all non-TOE-guided cardioversions, 80% of procedures on NOACs and 67% of procedures on warfarin were performed within 25 days (P < 0.001). Thromboembolism occurred in one patient (0.15%) receiving NOAC and in two patients (0.14%) receiving warfarin (risk ratio (RR) 1.07; 95% confidence interval (CI) 0.10-11.81). Major bleeding events occurred in four patients (0.58%) in the NOAC group and 11 patients (0.75%) in the warfarin group (RR 0.78; 95% CI 0.25-2.43). Conclusion: In a real-world clinical setting with anticoagulation handled in a structured multidisciplinary AF clinic, the waiting time to cardioversion was shorter with NOACs compared to warfarin. The rates of thromboembolism and major bleeding events were low, with NOACs shown to be as effective and safe as warfarin.

[A structured multidisciplinary approach ensures correct anticoagulation therapy to patients with atrial fibrillation]. / En struktureret tværfaglig tilgang sikrer patienter med atrieflimren korrekt antikoagulationsbehandling.

Atrial fibrillation (AF) is associated with an increased risk of stroke and mortality. Anticoagulation therapy reduces the risk of stroke in patients with AF. In a structured multidisciplinary AF-clinic correct anticoagulation treatment according to guidelines was achieved in 99% (170 out of 172 patients) compared to 79% (143 out of 179 patients) in the "usual care" period (p < 0.001). We propose establishment of structured multidisciplinary AF-clinics in Denmark to ensure optimal antithrombotic treatment and adherence to current guidelines.

Adverse effect of right ventricular pacing prevented by biventricular pacing during long-term follow-up: a randomized comparison.

AIMS: To investigate whether biventricular (BIV) pacing preserves left ventricular ejection fraction (LVEF) and reduces LV dyssynchrony when compared with standard dual-chamber right ventricular (RV) pacing in consecutive patients with high-grade atrioventricular block during 3 years of pacing. METHODS AND RESULTS: Fifty patients were randomized to RV pacing or BIV pacing. LVEF was measured using three-dimensional echocardiography. Tissue Doppler imaging was used to quantify LV dyssynchrony in terms of the standard deviation of the time-to-peak velocity (Ts-SD). LVEF differed significantly between the two groups during 3 years of pacing (ANOVA: P=0.003). LVEF in the RV group decreased from 59±5% at baseline to 53±11% (P=0.01), while LVEF remained unchanged in the BIV group (57±7% at baseline vs. 58±10% (P=0.40). After 3 years of follow-up, we observed no difference in LV dyssynchrony, LV remodelling or measurements of clinical heart failure (N-terminal pro-brain natriuretic peptide, walking test, and New York Heart Association functional class) between the two groups. However, in the RV group, but not in the BIV group, dyssynchrony increased significantly (P=0.005) during follow-up. Furthermore, adverse LV remodelling was observed in the RV group with increased systolic volume and thinning of the LV septum. CONCLUSION: BIV pacing preserves LVEF and minimizes LV dyssynchrony during long-term follow-up. Adverse remodelling observed during 3 years of RV pacing was prevented by BIV pacing. However, the adverse impact of RV pacing on LV function was not reflected in measures of clinical heart failure. CLINICAL TRIAL REGISTRATION: www.clinicaltrials.gov (identification number: NCT00228241).

Long-term clinical outcome and left ventricular lead position in cardiac resynchronization therapy.

AIMS: To identify the predictive value of a presumed optimal left ventricular lead positions (LV-Ps) on the long-term clinical outcome in patients with cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Clinical information was collected from patient files in consecutive patients treated with CRT from 1997 to 2007. A presumed optimal LV-Ps were defined as a position between 2 and 5 o'clock in the short-axis circumference and basal or mid-ventricular in the long axis. Symptomatic response was defined as improvement in NYHA class (>or=1) and echocardiographic response as improvement in left ventricular ejection fraction of >or=5% absolute. We included 567 patients [median age 66 years, 453 (80%) male]. The LV-Ps were optimal in 334 (59%) patients. The hazard ratio for all-cause mortality with an optimal LV-Ps was unadjusted 0.79 (0.59-1.06) and adjusted 0.99 (0.71-1.40). The odds ratio (OR) for symptomatic response with an optimal LV-Ps was unadjusted 1.13 (0.79-1.64) and adjusted 1.05 (0.67-1.64), and the OR for echocardiographic response was unadjusted 1.60 (1.02-2.49) and adjusted 1.42 (0.88-2.31). CONCLUSION: A presumed optimal LV-Ps between 2 and 5 o'clock in the short-axis circumference and basal or mid-ventricular in the long axis is not associated with a lower mortality or a better clinical response in patients treated with CRT.

Simple preimplant identification of optimum VV timing before cardiac resynchronization therapy: tissue Doppler imaging versus conventional 2D echocardiography.

AIMS: Optimum interventricular (VV) timing may potentially reduce the number of nonresponders to cardiac resynchronization therapy (CRT). We investigated whether optimum VV-timing interval could be determined before CRT implantation by means of tissue Doppler imaging (TDI) analysis and from visual assessment of conventional 2D echocardiography. METHODS AND RESULTS: Thirty consecutive patients prospectively underwent 2D, 3D, and TDI echocardiographic evaluation before and 1 month after CRT. By using 3D echocardiography, LVEF was found to be increased from 23.8 +/- 6% to 35.7 +/- 9% 1 month after CRT (P < 0.001). NYHA class improved from 3.0 +/- 0.6 to 1.8 +/- 0.6 (P < 0.001). In 93% (77-99% with 95% confidence limits) of the patients optimum VV timing was correctly predicted based on preimplant TDI identification of the region with delayed myocardial contraction. A similar result could be obtained in 83% (65-94%) of the patients simply by visual assessment of conventional black and white 2D echocardiography (ns). CONCLUSION: Preimplant TDI evaluation seems to be convenient for the determination of optimum VV timing. Further postimplant adjustment guided by TDI is hardly necessary unless patients do not experience clinical benefit. TDI may seem superior to visual assessment of dyssynchrony by means of conventional 2D echocardiography. However, this simple technique indicated optimum VV timing in the majority of cases in this study.

DDD(R)-pacing, but not AAI(R)-pacing induces left ventricular desynchronization in patients with sick sinus syndrome: tissue-Doppler and 3D echocardiographic evaluation in a randomized controlled comparison.

AIMS: Increasing evidence from randomized trials and experimental studies indicates that right ventricular (RV) pacing may induce congestive heart failure. We studied regional left ventricular (LV) dyssynchrony and global LV function in 50 consecutive patients with sick sinus syndrome (SSS) randomized to either atrial pacing [AAI(R)] or dual chamber RV-pacing [DDD(R)]. METHODS AND RESULTS: Fifty consecutive patients were randomized to AAI(R) or DDD(R)-pacing. Tissue-Doppler imaging was used to quantify LV dyssynchrony in terms of number of segments with delayed longitudinal contraction (DLC). Left ventricular ejection fraction (LVEF) was measured using three-dimensional echocardiography. Dyssynchrony was more pronounced in the DDD(R)-group than in the AAI(R)-group at the 12 months follow-up (P < 0.05). This reflected a significant increase of dyssynchrony in the DDD(R)-group from baseline to the 12 months follow-up (1.3 +/- 1 to 2.1 +/- 1 segments displaying DLC per patient), P < 0.05. No change was observed in the AAI(R)-group (1.6 +/- 2 to 1.3 +/- 2 segments displaying DLC per patient, NS). No difference in LVEF, NYHA or NT-proBNP was observed between AAI(R)- and DDD(R)-mode after 12 months of pacing although LVEF decreased significantly in the DDD(R)-group from baseline (63.1 +/- 8%) to the 12 months follow-up (59.3 +/- 8%, P < 0.05), while LVEF remained unchanged in the AAI(R)-group (61.5 +/- 11% at baseline vs. 62.3 +/- 7% after 12 months, NS. CONCLUSION: In patients with SSS, DDD(R)-pacing but not AAI(R)-pacing induces significant LV desynchronization and reduction of LVEF.

Left ventricular lead performance in cardiac resynchronization therapy: impact of lead localization and complications.

INTRODUCTION: Cardiac resynchronization therapy (CRT) using left ventricular (LV) pacing from the coronary sinus tributary is increasingly and frequently used in patients with severe congestive heart failure. The present study investigates LV lead performance in different anatomic locations. METHODS: The LV pacing site was defined by bi-plane fluoroscopy. In the left anterior oblique view, the coronary sinus is encircling the mitral ring with the tributaries radiating out like the hands of a watch. Using this clockwise method, Group A had an LV pacing site before 3 o'clock and Group B at or after 3 o'clock. In right anterior oblique view, the LV was divided into three segments: basal, mid-ventricular, and apical. RESULTS: LV lead implantation was successful in all of 120 consecutive patients. Mean follow-up was 16.7 months. Implantation time decreased from mean 190 to 80 minutes during the period (P = 0.01). The mean LV lead stimulation threshold increased initially and stabilized afterwards. The threshold measured at last follow-up was higher than at implantation (2.3 vs 2.7 microJ, P = 0.04). Useful venograms were obtained in 94 patients. No significant difference in thresholds was observed between Groups A and B. Phrenic nerve stimulation was most commonly seen in Group B (8/70 vs 1/24, P = 0.001). CONCLUSION: Implantation of an LV lead for CRT is possible in patients with congestive heart failure and associated with an acceptable low complication rate. LV lead implantation is associated with a learning curve. At mid-term follow-up, LV lead performance is stable and unrelated to the LV implantation site.