Dobutamine stress echocardiography (DSE) detects coronary artery disease (CAD) by increasing myocardial oxygen demand causing ischemia. Determinants of myocardial oxygen demand are contractility, heart rate and blood pressure. Though dobutamine increases contractility, its effects on heart rate and systolic blood pressure (SBP) are variable. In patients that do not reach 85% of predicted maximal heart rate during DSE, addition of atropine improves the sensitivity of the test for detection of CAD. Whether augmentation of SBP further improves detection of CAD during DSE is presently unknown. Isometric exercise, using hand grip (HG), is a simple method for augmenting SBP. To assess whether addition of HG improves the detection of CAD during DSE we studied 24 pts, mean age 56±11 yrs, with CAD (>50% stenosis in at least one epicardial vessel) and normal rest wall motion (WM). Dobutamine was incrementally infused up to 40 mcg/kg/min and up to 1 mg of atropine was given if heart rate remained <85% of predicted maximal. In pts with SBP <180mmHg, HG was then performed at 33% of maximal voluntary contraction for 2 minutes while maintaining dobutamine infusion. For analysis the ventricle was divided into 16 segments, grouped into 3 vascular regions. Using digitized echo images, segmental WM at rest, peak dobutamine-atropine and HG was interpreted without knowledge of clinical data or stage of stress, and WM score indices (WMSI) were calculated. In 3 pts the test was terminated prior to HG due to angina in 2 and SBP >220mmHg in 1. SBP (mmHg) increased from 125±20 at rest to 148±31 at peak dobutamine (p <.01) and further rose to 166±25 with HG (p <.01 vs dobutamine). Peak WMSI during DSE was 1.11±07 and increased to 1.27±11 following HG (p =.02 vs dobutamine). CAD was detected in 14 pts (58%) with DSE and 17 pts (71%) with DSE and HG (p = .04). Of 31 vascular regions supplied by a vessel with >50% stenosis, segmental WM abnormalities developed in 16 (52%) with DASE and 21 (68%) with HG. Multivessel CAD was present in 7 pts. Ischemia was detected in at least 1 vascular region in 6/7 pts before and all 7 after HG. However, WM abnormalities in >1 vascular regions were detected in 2/7 (29%) pts with DSE alone and 4/7 (57%) after HG. These findings suggest that augmentation of SBP by isometric exercise improves the detection of CAD during DSE.
|Original language||English (US)|
|Number of pages||1|
|Journal||Journal of the American Society of Echocardiography|
|State||Published - Dec 1 1997|
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Cardiology and Cardiovascular Medicine