K Galatro | PubMed Health

PubMed2000

Prognostic implications of myocardial contractile reserve in patients with ischemic cardiomyopathy.

The extent and degree of myocardial viability is an important parameter in the risk stratification of patients with significant left ventricular dysfunction due to coronary artery disease (CAD). Although several imaging modalities can identify viable myocardium, dobutamine stress echocardiography has gained considerable importance as an accurate, safe, and reliable method. In patients with significant left ventricular dysfunction secondary to CAD, identifying the presence and extent of contractile reserve and, therefore, viable myocardium, during low dose dobutamine infusion can predict recovery of left ventricular function postrevascularization, survival, and future cardiac events.

Cardiotonic Agents↗

PubMed2000

Reversible left ventricular dysfunction.

The extent and degree of myocardial viability are important parameters in the risk stratification of patients with significant left ventricular dysfunction secondary to coronary artery disease. Although several imaging modalities can identify viable myocardium, dobutamine stress echocardiography has gained considerable importance as an accurate, safe, and reliable method. In patients with significant left ventricular dysfunction secondary to coronary artery disease, identification of the presence and extent of contractile reserve and, therefore, viable myocardium during low-dose dobutamine infusion can predict the recovery of left ventricular function after revascularization, survival rate, and future cardiac events.

Contrast Media↗

PubMed1999

Comparison of dobutamine echocardiography, dobutamine sestamibi, and rest-redistribution thallium-201 single-photon emission computed tomography for determining contractile reserve and myocardial ischemia in ischemic cardiomyopathy.

Both dobutamine stress echocardiography (DSE) and myocardial perfusion scintigraphy are used to assess myocardial viability. Few studies have compared the data on myocardial viability and ischemia by low and peak dose DSE and myocardial perfusion imaging in the same patients. Fifty-four patients (45 men and 9 women aged 65 +/- 9 years) with ischemic cardiomyopathy (mean ejection fraction 24 +/- 9%) underwent rest 4-hour redistribution thallium-201 single-photon emission computed tomography (SPECT), low and peak dose DSE, and dobutamine sestamibi SPECT. A total of 864 segments were analyzed (16 segments/patient). Wall motion abnormality was present in 796 segments (92%), and contractile reserve during dobutamine infusion was seen in 400 of these segments (50%). Contractile reserve was seen in 331 of 509 hypokinetic segments (65%) and 69 of 287 akinetic/dyskinetic segments (24%) (p <0.001). Contractile reserve was more frequent in segments with normal thallium uptake (64%), reversible thallium defects (42%), or mild to moderate fixed thallium defects (48%) than severely fixed defects (22%) (p <0.05 each). Concordant information about viability by thallium imaging and DSE was obtained in 62% of segments. Dobutamine sestamibi ischemia was seen in 518 of 796 segments (65%) compared with 265 segments (33%) by DSE (p <0.001). Scintigraphic ischemia was noted in 126 of 195 segments (65%) demonstrating biphasic response, 129 of 205 segments (63%) showing sustained improvement, 42 of 70 segments (60%) deteriorating during dobutamine infusion, and 221 of 326 (68%) demonstrating no change (p = NS). Thus, in patients with ischemic cardiomyopathy, contractile reserve is more frequent in hypokinetic segments than akinetic/dyskinetic segments. The number of segments with normal or near-normal thallium uptake or with scintigraphic ischemia is significantly greater than the number of those capable of increasing contractile function or demonstrating an ischemic response during dobutamine echocardiography.

Adult↗