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Background To test whether later intra-aortic balloon pump (IABP) deflation approaching or simultaneous with left ventricular ejection would improve hemodynamics and myocardial efficiency with the use of new balloon deflation methods, 4 IABP timing techniques were evaluated in 43 patients. Methods and Results Later balloon deflation produced significantly greater percentage changes in mean aortic pressure (6% vs 1%), systolic pressure time index (-27% vs -20%), diastolic pressure time index (35% vs 19%), and the systolic pressure-time index/diastolic pressure-time index ratio (97% vs 51%), respectively. However, these changes increased peak systolic pressure (-15% vs -11%). Cardiac output and stroke volume indexes were not significantly altered over the 4 settings. Conclusions These data suggest that systemic hemodynamics and myocardial efficiency may be improved by later balloon deflation approaching left ventricular ejection in comparison to conventional IABP timing. (Am Heart J 1999;137:1129-6.)

We compared exercise test results to a physiologic depiction of stenosis severity, coronary flow reserve (CFR), measured with a Doppler guide wire in 35 patients with single-vessel coronary disease. Group 1 ( n = 21) had abnormal CFR, and group 2 ( n = 14) had normal CFR. In group 1, 14 of 21 had ST-segment depression versus 3 of 14 in group 2 ( p < 0.01). Exercise treadmill time (Bruce protocol) was normalized to the age- and sex-predicted time. Exercise time and normalized exercise time were less in group 1 (5.6 +/- 2.3 vs 9.9 +/- 1.8 min and 0.82 +/- 0.32 vs 1.25 +/- 0.23, p < 0.00001). Having either ST-segment depression or a normalized exercise time <1 during exercise had a 95% sensitivity, 71% specificity, and 86% predictive accuracy in identifying abnormal CFR. Coronary stenoses and minimal lumen diameter were similar in groups 1 and 2. By using stepwise logistical regression analysis, exercise time and ST-segment depression predicted CFR with a total r^2 of 0.51. Minimal lumen diameter did not significantly add to the model. Exercise test variables, ST-segment depression, and exercise time are predictive of the physiologic significance of coronary lesions. (Am Heart J 1997;134:99-104.)