There is limited in vivo data in humans evaluating myocardial fat utilization during increased heart work. This study was done to determine myocardial free fatty acid (FFA) metabolism during rest and atrial pacing, which increases cardiac work without changing arterial substrate concentration. We studied seven healthy men and women (age = 49.7 +/- 3.9 yr, BMI = 23.4 +/- 1.1 kg/m(2), Vo(2max) = ...

OBJECTIVES This study was designed to assess the impact of prevention of bradycardia with physiologic pacing on the severity of obstructive sleep apnea. BACKGROUND Apneic episodes during sleep are associated with slowing of the heart rate during apnea and tachycardia with subsequent arousal. Patients with permanent pacemakers may have reduced episodes of sleep apnea when their pacemaker rate ...

SUMMARY The purpose of this study was to determine the prevalence of repetitive ventricular responses caused by non-bundle-branch re-entry and bundle-branch re-entry in 47 patients with and in 50 patients without ventricular tachycardia. We also compared the prevalence of repetitive ventricular responses using two types of electrophysiological stimulation: single premature ventri-cular stimulat...

In areflexic canine right heart bypass preparations, little difference in ventricular function was observed as a result of atrial pacing, sequential atrioventricular pacing, or atrial-His bundle pacing at an appropriate atrial systole-ventricular systole (As-Vs) interval. Ventricular function was depressed during ventricular pacing and during atrioventricular pacing with an inappropriate As-Vs ...

M mode echocardiography was used in 10 normal subjects to study left ventricular dimension and function variables at identical heart rates during tachycardia induced by supine bicycle exercise or atrial pacing. Echocardiographic data were analysed independently by two observers. The maximum heart rate reached during atrial pacing was lower (mean (1SD) 148 (17) beats/min) than that reached durin...

Background: Atrial fibrillation (AF) after coronary artery bypass graft surgery (CABG) constitutes the most common arrhythmia and results in morbidity and prolonged hospitalization secondary to hemodynamic decompensation. Although pharmacologic therapy has been used to help prevent postoperative atrial fibrillation, it suffers from limited efficacy and adverse effects. In the non operative sett...

OBJECTIVE To determine the relations between left atrial appendage function, spontaneous echo contrast, and thromboembolism in patients with different modes of permanent pacemakers. PATIENTS AND METHODS 88 patients with pacemaker implantation and 25 healthy controls in sinus rhythm had transoesophageal echocardiographic examination of the left atrial appendage. Left atrial size, appendage are...

BACKGROUND In a previous study of 225 patients with sick-sinus syndrome randomised to either single-chamber atrial pacing (n=110) or single-chamber ventricular pacing (n=115), we found that after a mean follow-up of 3.3 years, atrial pacing was associated with significantly less atrial fibrillation and thromboembolism whereas there was no significant difference in mortality and heart failure be...

BACKGROUND Inadvertent capture of the atrium will lead to spurious results during para-Hisian pacing. We sought to establish whether the stimulation-to-atrial electrogram interval at the proximal coronary sinus (stim-PCS) or high right atrium (stim-HRA) could signal inadvertent atrial capture. METHODS AND RESULTS Para-Hisian pacing with and without intentional atrial capture was performed in ...

BACKGROUND The coronary sinus (CS) was, for 10 years, the standard place for permanent atrial pacing, and the antiarrhythmic properties of CS pacing were described by Moss in the early 70's. These observations were confirmed during EP studies, although currently permanent CS pacing is infrequently applied. Signal averaged (SA) P wave analysis has established values for the examination of EP pro...