Biomedical subjects

R S Alessandrini

Publications and source records attributed to R S Alessandrini.

3 recordsLinked to original sources

PubMed2000

Enhanced detection of ischemic myocardium by transesophageal dobutamine stress echocardiography: comparison with simultaneous transthoracic echocardiography.

The diagnostic accuracy of dobutamine stress echocardiography is limited in patients with poor transthoracic acoustic windows. Transesophageal echocardiography (TEE) overcomes these limitations and thus may increase the clinical usefulness of dobutamine stress echocardiography. The present study was designed to compare the diagnostic accuracies of transesophageal and transthoracic dobutamine stress echocardiography for the identification of coronary artery disease (CAD) in a cohort of patients with a higher incidence of poor acoustic windows. Forty-two male patients (mean age, 66 +/- 9 years) underwent dobutamine stress echocardiography with simultaneous transesophageal and transthoracic imaging. Coronary arteriography was performed in 28 patients (67%). Transesophageal imaging adequately visualized 99.6% of left ventricular segments compared with 76.2% visualized by transthoracic imaging (P < 0.0001). There was substantial agreement between the two techniques for segmental wall motion analysis at baseline (kappa 0.76; 95% CI, 0.70-0.82); however, at peak dobutamine dose, agreement was significantly reduced (kappa 0.62; 95% CI, 0.55-0.69). The sensitivity (88% vs 75%), specificity (100% vs 75%), and positive predictive value (100% vs 80%) for the identification of CAD were all superior for transesophageal imaging. Transesophageal imaging correctly identified 11 of the 12 patients (92%) with multivessel disease compared with 5 patients (42%) identified by transthoracic imaging (P < 0.03). There were no major complications. Transesophageal dobutamine stress echocardiography is a safe, feasible, and accurate technique for the identification and risk stratification of patients with CAD. Transesophageal imaging appears to be superior to transthoracic imaging for identifying both the presence and extent of CAD, specifically in patients with poor acoustic windows.

Aged↗

PubMed1999

Prognostic implications of myocardial contractile reserve in patients with coronary artery disease and left ventricular dysfunction.

OBJECTIVES: This study was performed to assess the prognostic implications of myocardial contractile reserve (MCR) in patients with coronary artery disease (CAD) and left ventricular (LV) dysfunction. BACKGROUND: MCR during dobutamine stress echocardiography (DSE) identifies viable myocardium that may improve in function after revascularization. Whether revascularization influences prognosis of patients with MCR has not been determined. METHODS: We performed DSE in 80 patients with CAD and LV dysfunction (ejection fraction < or =40%). Viable myocardium was defined in dysfunctional myocardial segments as enhanced thickening and contraction during low-dose dobutamine (5 to 10 mcg/kg/min). Serial prospective follow-up was obtained in all patients (mean follow-up 2.2 +/- 1.1 years). RESULTS: Among 52 patients treated medically, there were 20 cardiac deaths. By multivariate analysis, the number of dysfunctional segments demonstrating MCR was the strongest predictor of survival (p < 0.03). Patients with MCR had better initial survival during medical therapy than did those without MCR, but this survival advantage was not maintained beyond three years. In contrast, survival was excellent in patients with MCR who underwent myocardial revascularization. Among 58 patients with MCR in > or =5 myocardial segments, survival at three years was 93 +/- 6% in the 24 patients who were revascularized but only 49 +/- 15% in the 34 treated medically (p < 0.02). CONCLUSIONS: Myocardial contractile reserve is a significant predictor of survival in patients with CAD and LV dysfunction undergoing medical therapy. Although patients with MCR have an initial survival advantage, this advantage is lost over the course of three years. In contrast, survival in patients with significant MCR is enhanced by revascularization.

Adult↗

PubMed1997

Cardiac memory: a mechanical and electrical phenomenon.

Alterations in repolarization following prolonged periods of ventricular pacing, termed "cardiac memory," have been well documented. Postpacing changes in cardiac function have also been noted in hypertrophic cardiomyopathy. This study was designed to evaluate the effects of ventricular pacing on postpacing diastolic function and its relationship to repolarization changes. Eight subjects (mean age, 76 yr) with permanent pacemakers were enrolled in this study. Each subject was evaluated at a fixed pacing rate with recording of electrocardiographic and echocardiographic data. Seven sets of measurements were performed in the same sequential pattern: 1) after 1 wk of atrial pacing, 2) within 10 min after initiation of atrioventricular sequential pacing (ventricular pacing), 3) within 10 min after termination of 1 h of ventricular pacing, 4) after 1 wk of ventricular pacing, and 5) within 10 min, at 1 h, and at 24 h after termination of ventricular pacing. All subjects had repolarization changes characteristic of cardiac memory only after 1 wk of ventricular pacing. Changes in repolarization parameters were accompanied by changes in peak left ventricular filling rate (dD/dt/D; P = 0.02) and isovolumic relaxation time (IVRT; P = 0.03) that at 24 h approached baseline values. Correlations existed between changes in the Q-T interval and IVRT (r = 0.53, P = 0.007) and between changes in T wave amplitude and dD/dt/D (r = 0.48, P = 0.018) after long-term ventricular pacing. Thus changes in both repolarization and diastolic function persist after cessation of ventricular pacing and lend support to the concept of electrical and mechanical cardiac memory.

Aged↗