Biomedical subjects

Frank J Zimmerman

Publications and source records attributed to Frank J Zimmerman.

4 recordsLinked to original sources

PubMed2006

Cardiac conduction disturbances seen after transcatheter device closure of muscular ventricular septal defects with the Amplatzer occluder.

This study examined the incidence of cardiac conduction abnormalities and ventricular arrhythmias after the transcatheter closure of muscular ventricular septal defects (MVSDs) using the Amplatzer device occluder. From the records of 27 patients who underwent 33 consecutive MVSD device closures, a low incidence of permanent and transient cardiac conduction disturbances was observed. Heart rate variability was less after the closure of multiple MVSDs compared with single MVSDs.

Adolescent↗

PubMed2005

Resynchronization therapy in pediatric and congenital heart disease patients: an international multicenter study.

OBJECTIVES: Our objective was to evaluate the short-term safety and efficacy of cardiac resynchronization therapy (CRT) in children. BACKGROUND: Cardiac resynchronization therapy has been beneficial for adult patients with poor left ventricular function and intraventricular conduction delay. The efficacy of this therapy in the young and in those with congenital heart disease (CHD) has not yet been established. METHODS: This is a multi-center, retrospective evaluation of CRT in 103 patients from 22 institutions. RESULTS: Median age at time of implantation was 12.8 years (3 months to 55.4 years). Median duration of follow-up was four months (22 days to 1 year). The diagnosis was CHD in 73 patients (71%), cardiomyopathy in 16 (16%), and congenital complete atrioventricular block in 14 (13%). The QRS duration before pacing was 166.1 +/- 33.3 ms, which decreased after CRT by 37.7 +/- 30.7 ms (p < 0.01). Pre-CRT systemic ventricular ejection fraction (EF) was 26.2 +/- 11.6%. The EF increased by 12.8 +/- 12.7 EF units with a mean EF after CRT of 39.9 +/- 14.8% (p < 0.05). Of 18 patients who underwent CRT while listed for heart transplantation, 3 improved sufficiently to allow removal from the transplant waiting list, 5 underwent transplant, 2 died, and 8 others are currently awaiting transplant. CONCLUSIONS: Cardiac resynchronization therapy appears to offer benefit in pediatric and CHD patients who differ substantially from the adult populations in whom this therapy has been most thoroughly evaluated to date. Further studies looking at the long-term benefit of this therapy in this population are needed.

Adolescent↗

PubMed2004

Ventricular resynchronization by multisite pacing improves myocardial performance in the postoperative single-ventricle patient.

BACKGROUND: Ventricular resynchronization with multisite pacing in heart failure patients results in acute improvement of myocardial performance, but the mechanism is unknown. Our goals were to determine whether multisite pacing results in acute improvement of myocardial performance in postoperative single-ventricle patients, and to elucidate the mechanism by assessing the synchronization of regional ventricular contraction during multisite pacing using real-time three-dimensional echocardiographic imaging. METHODS: Multisite pacing studies were performed in 26 single-ventricle patients (mean age, 28 months; range, 7 days to 11 years) undergoing some form of single-ventricle palliation (stage I Norwood, 4; aortopulmonary shunt, 1; cavopulmonary shunt, 9; Fontan, 8; Fontan revision, 3; valve replacement, 1). Electrocardiogram, blood pressure, mixed-venous oxygen saturation, and three-dimensional echocardiograms (n = 10) were recorded at baseline and during multisite pacing. Data were analyzed to obtain regional volume-time curves for 16 three-dimensional segments of the systemic ventricle. An index of asynchrony was calculated at baseline and during pacing as the standard deviation of all segmental volume-time curves from onset to end of ejection. RESULTS: With multisite pacing performed at a median postoperative day 2 (range, 0 to 9), QRS duration decreased in 24 of 26 patients (93.9 +/- 17.5 versus 71.7 +/- 10.8 ms; p < 0.001); systolic blood pressure increased in 25 of 26 patients (86.3 +/- 20.0 versus 93.8 +/- 20.2 mm Hg; p < 0.001); cardiac index increased in 21 of 22 patients (3.2 +/- 0.8 versus 3.7 +/- 1.0 L x min(-1) x m(-2); p < 0.001); and the index of asynchrony improved in 8 of 10 patients (10.3 +/- 4.8 versus 6.0 +/- 1.4; p < 0.04). CONCLUSIONS: Multisite pacing improves cardiac performance after single-ventricle palliation. Real-time three-dimensional echocardiography demonstrated that multisite pacing improved the synchrony of ventricular contraction.

Cardiac Pacing, Artificial↗

PubMed2003

Acute hemodynamic benefit of multisite ventricular pacing after congenital heart surgery.

BACKGROUND: Cardiac dysfunction after congenital heart surgery is a major cause of morbidity and mortality. Cardiac resynchronization through multisite ventricular pacing (MSVP) improves cardiac index and ventricular function, and lowers systemic vascular resistance (SVR) in adults with heart failure and interventricular conduction delay. METHODS: The acute hemodynamic effects of MSVP after congenital heart surgery were assessed. Twenty-nine patients (aged 1 week to 17 years) with prolonged QRS interval had atrial and ventricular unipolar epicardial temporary pacing leads placed at surgery. Group 1 consisted of patients with a single ventricle (n = 14); group 2 included patients with two-ventricle anatomy (tetralogy of Fallot, ventricular septal defect) undergoing ventricular surgery (n = 10); and group 3 included patients with two-ventricle anatomy undergoing other cardiac surgery (n = 5). At a mean postoperative day 1 (range, 0 to 6), blood pressure, systemic and mixed venous oxygen saturations, electrocardiograms, and echocardiograms were obtained before and after 20 minutes of MSVP. RESULTS: The QRS duration decreased with MSVP in all patients (mean, 23%, p < 0.005). Systolic blood pressure improved in all patients (mean, 9.7%, p < 0.005). Cardiac index improved in 19 of 21 patients tested, with no change in 2 patients (mean, 15.1%, p = 0.0001). In 2 patients, MSVP facilitated weaning from cardiopulmonary bypass. Echocardiographic mitral or tricuspid valve inflow was not significantly different with MSVP. CONCLUSIONS: Multisite ventricular pacing results in improved cardiac index and increased systolic blood pressure, and it can also facilitate weaning from cardiopulmonary bypass. Multisite ventricular pacing may be used as adjunct to standard postoperative treatment of cardiac dysfunction after congenital heart surgery.

Adolescent↗