Important questions exist about the relative roles of changes in heart rate versus extent of myocardial shortening in regulating fetal cardiac output, because increases in heart rate created by left atrial pacing have been shown to increase right ventricular output and decrease left ventricular output. Since the pacemaker site could importantly influence foramen ovale flow and, hence, each vent...

Background: Cardiac resynchronization therapy (CRT) improves cardiac function in patients with heart failure by synchronizing contraction of the right and left ventricles (RV, LV). This study was to determine if electrical stimulation during the refractory period of bi-ventricular (BiV) pacing would provide additional LV mechanical improvement. Methods: 16 patients receiving CRT-ICD devices wer...

To observe blood B-type natriuretic peptide (BNP) level changes and the clinical implications in different periods and different cardiac pacing modes, the BNP levels of 105 patients with permanent cardiac pacing were assayed before pacemaker implantation and 1 day, 1 week, 1 month, 3 months, 6 months, and 9 months postoperatively. BNP level changes were compared in different periods and during ...

OBJECTIVES The objective of this study was to determine whether the threshold for successful cardiac pacing is affected by electrode impedance and whether this procedure can be successfully carried out through low impedance electrodes that are also suitable for defibrillation. BACKGROUND Reintroduced in the early 1980s, external cardiac pacing utilizes large externally placed electrodes with ...

PURPOSE:To determine the indication for and incidence and evolution of temporary and permanent pacemaker implantation in cardiac transplant recipients. METHODS: A retrospective review of 114 patients who underwent orthotopic heart transplantation InCor (Heart Institute USP BR) between March 1985 and May 1993. We studied the incidence of and indication for temporary pacing, the relationship betw...

Echocardiography plays an integral role in the detection of mechanical dyssynchrony in patients with congestive heart failure and in predicting beneficial response to cardiac resynchronization treatment. In patients who derive sup-optimal benefit from biventricular pacing, optimization of atrioventricular delay post cardiac resynchronization treatment has been shown to improve cardiac output. S...

Through the use of a dual chamber (DDD) pacemaker, we achieved a cardiac resynchronization effect in a 51-year-old female patient who was transferred to our hospital from another hospital for an operation for three-vessel coronary artery disease. Her electrocardiogram showed a left bundle branch block (LBBB) and a prolonged QRS interval of 166 milliseconds. Severe left ventricle (LV) dysfunctio...

Optimal pacing strategies employed after CPB enhance ventricular function with improvements in cardiac output and tissue perfusion. Pacing is optimized for each patient by taking into consideration the underlying electrophysiological abnormalities, as well as co-existing structural cardiac diseases. The primary objective of rhythm stability and improved cardiac function in the post-CPB period i...

Congestive heart failure is associated with cardiac adrenergic nerve terminal changes and beta-adrenoceptor density downregulation. To study the temporal sequence of these changes, we performed studies in rabbits at 2, 4, and 8 wk of cardiac pacing (360 beats/min) and at 1, 2, and 4 wk after cessation of pacing. Rapid pacing produced left ventricular (LV) dysfunction and an increase in plasma n...

Cardiac resynchronization therapy is not commonly used in the early postoperative period in patients undergoing cardiac surgery who have left ventricular (LV) dysfunction and a history of heart failure. We performed a prospective randomized clinical trial to compare atrial synchronous right ventricular (DDD RV) and biventricular (DDD BIV) pacing within 72 hours after cardiac surgery in patients...