Efficacy of low interatrial septum and right atrial appendage pacing for prevention of permanent atrial fibrillation in patients with sinus node disease: results from the electrophysiology-guided pacing site selection (EPASS) study.

BACKGROUND: The role of pacing sites and atrial electrophysiology on the progression of atrial fibrillation (AF) to the permanent form in patients with sinus node dysfunction (SND) has never been investigated. The aim of the study was to investigate the relationship between atrial electrophysiology and the efficacy of atrial pacing at the low interatrial septum (IAS) or at the right atrial appendage (RAA) to prevent persistent/permanent AF in patients with SND. METHODS AND RESULTS: The Electrophysiology-Guided Pacing Site Selection (EPASS) Study was a prospective, controlled, randomized study. Atrial refractoriness, basal and incremental conduction times from the RAA to the coronary sinus ostium were measured before implantation, and the difference (ΔCTos) was calculated. Patients with ΔCTos ≥ 50 ms (study group) and those with ΔCTos <50 ms (control group) were randomly assigned to RAA or IAS with algorithms for continuous atrial stimulation "on." The primary end point was time to development of permanent or persistent AF within a 2-year follow-up in the study group, IAS versus RAA. Data were analyzed by intention to treat. One hundred two patients (77 ± 7 years, 44 mol/L) were enrolled, 69 (68%) in the study group and 33 (32%) in the control group. Of these, 97 ended the study, respectively, randomly assigned: 29 IAS versus 36 RAA and 18 IAS versus 14 RAA. After a mean follow-up of 15 ± 7 (median, 17) months, 11 (16.6%) patients in the study group met the primary end point: 2 IAS versus 9 RAA (log rank=3.93, P=0.047). CONCLUSIONS: In patients with SND and intra-atrial conduction delay, low IAS pacing was superior to RAA pacing in preventing progression to persistent or permanent AF. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00239226.

Spinal cord stimulation affects T-wave alternans in patients with ischaemic cardiomyopathy: a pilot study.

AIMS: An antiarrhythmic effect of spinal cord stimulation (SCS) has been recognized in an animal model. The actual mechanism is still mainly unknown. An adrenergic output reduction has been advocated as the main mechanism, although a modulation effect on the arrhythmic substrate has not yet been investigated. We studied T-wave alternans (TWA) modifications to test the hypothesis that SCS affects the arrhythmic substrate. METHODS AND RESULTS: We performed TWA assessment in three high-risk patients who previously had undergone implantation of both implantable cardioverter defibrillator and SCS to treat refractory angina. The test was performed after switching off the SCS and after 2 and 24 h stimulation at the default amplitude. The protocol was executed 2 months apart in order to assess the reproducibility of the results, collecting a total of 18 TWA reports. In all the three patients, we observed a significant reduction of TWA amplitude after 2 h stimulation. All the tests were classified as negative after 24 h stimulation with the nominal parameters. CONCLUSION: Spinal cord stimulation results in a decrease in the TWA magnitude, and thus it seems to positively affect the arrhythmic substrate in a time-dependent manner.

Spinal cord stimulation for refractory angina in a patient implanted with a cardioverter defibrillator.

Spinal cord stimulation is currently used to treat refractory angina. Some concerns may arise about the possible interaction concerning the spinal cord stimulator in patients already implanted with a pacemaker or a cardioverter defibrillator. We are going to describe the successful implantation of a spinal cord stimulator in a patient previously implanted with a cardioverter defibrillator.