Comparison between dobutamine stress and combination of handgrip exercise with dobutamine stress in myocardial perfusion SPECT

AIM: We compared the efficacy, side effects of combined handgrip exercise and dobutamine stress with dobutamine stress alone during myocardial perfusion imaging in patients unable to exercise, and in whom vasodilator stress was contraindicated. METHODS: We studied 126 consecutive patients (89 male, 37 female; mean age 63+/-8 years) referred for dobutamine stress myocardial perfusion SPECT. Patients were divided into Group A (n=63), who underwent only dobutamine stress and group B (n=63) who were subjected to combined handgrip exercise and dobutamine infusion. In group A patients, dobutamine was administered at a starting dose of 5 microg x kg(-1) x min(-1) increased to 10, 20 and 30 microg x kg(-1) x min(-1) to a maximum dose of 40 microg x kg(-1) x min(-1) at 3 min intervals until the target heart rate (THR, 85% of age predicted maximum heart rate) or other standard end point criteria were achieved. Group B patients were made to perform handgrip exercise 3 min prior to dobutamine infusion and continued throughout the administration of dobutamine. RESULTS: In group A, 11 (17.6%) patients failed to achieve target heart rate even with infusion of maximum dose of dobutamine compared to two (3.2%) in group B (P<0.01). The mean dose of dobutamine infused in group A was significantly higher than in group B (36.2 vs. 23.5 microg x kg(-1) x min(-1), P<0.01). Minor non-cardiac side effects like anxiety; flushing and nausea were observed in 25% of group A and in 11% of group B (P<0.05). Cardiac side effects and arrhythmias in group A and B were observed in 22% vs. 14.3% and 9.5% vs. 1.6% respectively (statistically insignificant). CONCLUSION: Combination of handgrip exercise with dobutamine reduces the total dose of dobutamine required to achieve target heart rate and likely to minimize the side effects associated with dobutamine.