Biomedical subjects

Marc A Simon

Publications and source records attributed to Marc A Simon.

3 recordsLinked to original sources

PubMed2006

Right ventricular dyssynchrony in heart failure: a tissue Doppler imaging study.

BACKGROUND: The development of right ventricular dysfunction is a poor prognostic sign in patients with heart failure (HF). Although left ventricular dyssynchrony has been well described, it is not known whether right ventricular dyssynchrony coexists in HF. We used tissue Doppler imaging to determine whether right ventricular dyssynchrony is also present in HF patients. METHODS AND RESULTS: In 34 HF patients (mean age 56 +/- 13 years), we measured longitudinal strain at the right ventricular free wall, interventricular septum, and left ventricular lateral wall. Right ventricular and left ventricular dyssynchrony were defined as the difference in time to peak strain between the right ventricular free wall and the septum and between the left ventricular lateral wall and septum, respectively. Mean right ventricular dyssynchrony was 59 +/- 45 ms and the mean left ventricular dyssynchrony was 80 +/- 62 ms. We found a strong correlation between right ventricular dyssynchrony and pulmonary artery systolic pressure (r = 0.73; P < .001) and a negative correlation between right ventricular dyssynchrony and right ventricular fractional area change (r = -0.43; P < .02). CONCLUSION: HF patients exhibit right ventricular dyssynchrony by strain imaging which correlates with pulmonary hypertension and right ventricular dysfunction.

Adult↗

PubMed2005

Myocardial recovery using ventricular assist devices: prevalence, clinical characteristics, and outcomes.

BACKGROUND: Ventricular assist devices (VADs) are important bridges to cardiac transplantation. VAD support may also function as a bridge to ventricular recovery (BTR); however, clinical predictors of recovery and long-term outcomes remain uncertain. We examined the prevalence, characteristics, and outcomes of BTR subjects in a large single center series. METHODS AND RESULTS: We implanted VADs in 154 adults at the University of Pittsburgh from 1996 through 2003. Of these implants, 10 were BTR. This included 2/80 (2.5%) ischemic patients (supported 42 and 61 days, respectively). Both subjects had surgical revascularization, required perioperative left VAD support, and were alive and transplant-free at follow up (232 and 1319 days, respectively). A larger percentage of nonischemic patients underwent BTR (8/74, 11%; age 30+/-14; 88% female; left ventricular ejection fraction 18+/-6%; supported 112+/-76 days). Three had myocarditis, 4 had post-partum cardiomyopathy (PPCM), and 1 had idiopathic cardiomyopathy. Five received biventricular support. After explantation, ventricular function declined in 2 PPCM patients who then required transplantation. Ventricular recovery in the 6 nonischemic patients surviving transplant-free was maintained (left ventricular ejection fraction 54+/-5%; follow-up 1.5+/-0.9 years). Overall, 8 of 10 BTR patients are alive and free of transplant (follow-up 1.6+/-1.1 years). CONCLUSIONS: In a large single center series, BTR was evident in 11% of nonischemic patients, and the need for biventricular support did not preclude recovery. For most BTR subjects presenting with acute inflammatory cardiomyopathy, ventricular recovery was maintained long-term. VAD support as BTR should be considered in the care of acute myocarditis and PPCM.

Acute Disease↗

PubMed2005

Differential exercise performance on ventricular assist device support.

BACKGROUND: Ventricular assist devices (VADs) are approved for destination therapy because they improve survival in end-stage heart failure (HF). VADs are powered pneumatically or electrically. Pneumatic and electric left ventricular assist devices (LVADs) and biventricular assist devices (BiVADs) provide excellent hemodynamic support at rest, but differences in their effects on exercise tolerance are unclear. We sought to evaluate the effect of devices with varying operating parameters on exercise capacity. METHODS: Exercise physiology data obtained during maximal exercise with on-line gas-exchange analysis were collected for 38 consecutive VAD-implanted HF patients referred for exercise testing. RESULTS: Electric LVADs were implanted in 18 patients, and pneumatic LVADs in 10 patients. Percent of predicted peak exercise oxygen consumption (VO2%) was significantly greater in pneumatic LVAD patients (52.1 +/- 11.1% vs 38.2 +/- 11.3%, p < 0.05). The 10 patients implanted with a pneumatically powered LVAD were compared to 10 patients implanted with a pneumatically powered BiVAD. LVAD-supported patients had a higher VO2% (52.1 +/- 11.1% vs 36.5 +/- 17.7%, p < 0.05). CONCLUSIONS: HF patients supported with a pneumatic LVAD appear to have better exercise tolerance than those receiving an electric LVAD. Patients on LVAD support have better exercise tolerance than BiVAD-supported patients. This highlights the importance of right ventricular function to exercise tolerance in HF patients, and may have implications for future VAD design.

Adult↗