Optimal site for atrial lead implantation in myotonic dystrophy patients: the role of Bachmann's Bundle stimulation

Effect of dual-chamber minimal ventricular pacing on paroxysmal atrial fibrillation incidence in myotonic dystrophy type 1 patients: A prospective, randomized, single-blind, crossover study

BACKGROUND

Atrial fibrillation (AF) is a common finding in the myotonic dystrophy type 1 (DM1) population. Pacemakers (PMs) may facilitate the diagnosis and management of frequent subclinical asymptomatic AF episodes.

OBJECTIVE

The purpose of this study was to evaluate the effect of minimal ventricular pacing on paroxysmal AF incidence in DM1 patients during a 24-month follow-up period.

METHODS

We enrolled 70 DM1 patients (age 43.4 ± 13.8 years; 39 women) who underwent dual-chamber PM implantation. Patients were randomized to minimizing ventricular pacing features (ON) or not (OFF). Patients crossed over to the opposite pacing programming 12 months later. We counted the number of DM1 patients with at least 1 episode of AF, the AF total duration, and the burden recorded by PM diagnostics during the MVP ON and OFF phases.

RESULTS

Twenty-five DM1 patients (41.7%) showed at least 1 AF episode. Seven patients (11.7%) demonstrated AF episodes during MVP ON phase and 25 patients (41.7%) during MVP OFF phase (P <.001). Thirty-five patients had no AF during MVP ON or OFF phase, 3 patients had AF episodes only during MVP ON phase, 21 patients had AF episodes only during MVP OFF phase, and 4 patients had AF episodes during MVP ON and OFF phases. Activation of the MVP algorithm was associated with a 44% reduction in relative risk of developing AF. Furthermore, during the MVP ON phases, the study population showed a shorter total AF duration and a lower AF burden.

CONCLUSION

MVP is an efficacy strategy for reducing the risk of AF in DM1 patients who have undergone PM implantation.

The effect of aortic coarctation surgical repair on QTc and JTc dispersion in severe aortic coarctation newborns: a short-term follow-up study

Sudden death is a possible occurrence for newborns younger than 1 year with severe aortic coarctation (CoA) before surgical correction. In our previous study, we showed a significant increase of QTc-D and JTc-D in newborns with isolated severe aortic coarctation, electrocardiographic parameters that clinical and experimental studies have suggested could reflect the physiological variability of regional and ventricular repolarization and could provide a substrate for life-threatening ventricular arrhythmias. The aim of the current study was to evaluate the effect of surgical repair of CoA on QTc-d, JTc-d in severe aortic coarctation newborns with no associated congenital cardiac malformations. The study included 30 newborns (18M; 70+/-12 h old) affected by severe congenital aortic coarctation, without associated cardiac malformations. All newborns underwent to classic extended end-to-end repair. Echocardiographic and electrocardiographic measurements were performed in each patient 24 h before and 24 h after the interventional procedure and at the end of the follow-up period, 1 month after the surgical correction. All patients at baseline, 24 h and one month after CoA surgical repair did not significantly differ in terms of heart rate, weight, height, and echocardiographic parameters. There were no statistically significant differences in QTc-D (111.7+/-47.4 vs 111.9+/-63.8 ms vs 108.5+/-55.4 ms; P=0.4) and JTc-D (98.1+/-41.3 vs 111.4+/-47.5 vs 105.1+/-33.4 ms; P=0.3) before, 24 h and 1 month after CoA surgical correction. In conclusions, our study did not show a statistically significant decrease in QTc-D and JTc-D, suggesting the hypothesis that the acute left ventricular afterload reduction, related to successful CoA surgical correction, may not reduce the ventricular electrical instability in the short-term follow-up.