Adjunctive handgrip during dobutamine stress echocardiography: Invasive assessment of myocardial oxygen consumption in humans

Background: Adjunctive isometric exercise in the form of sustained submaximal handgrip (HG) is considered to increase the sensitivity of dobutamine stress echo (DSE) for detection of functionally significant coronary artery disease. Hypothesis: The study was undertaken to quantify invasively the impact of HG in humans,on hemodynamics and myocardial oxygen consumption (MVO2) during DSE. Methods: An invasive hemodynamic evaluation was performed during DSE and with addition of adjunctive HG in 11 subjects. Coronary sinus (CS) blood flow, right-sided and systemic pressures, oxygen saturations, and transthoracic two-dimensional echocardiography were obtained at each 3-min stage and after adding HG at peak DSE. Myocardial oxygen consumption was calculated by the Fick method and circumferential end-systolic wall stress (ESWS) by MitSky's formula. Results: At peak DSE, heart rate, left ventricular ejection fraction, CS flow, and MVO2 increased, whereas pulmonary capillary wedge pressure (PCWP) and circumferential endsystolic wall stress (ESWS) decreased from baseline. Compared with peak DSE, the addition of isometric HG at peak DSE caused an increase in PCWP (7 +/- 3 vs. 8.4 +/- 3 mmHg, p < 0.05), ESWS (112 25 X 103 vs. 125 32 X 103 dyne center dot s center dot cm(2), p = 0.02), and CS flow (260 92 vs. 301 105 ml/min, p < 0.05). There was a minimal increase in left ventricular volumes, heart rate, and systolic blood pressure. The MVO2 increased from 29 8 ml/min at peak DSE to 31 9 ml/min with adjunctive HG (p = 0.03). Conclusion: Handgrip adjunctive to peak DSE results in a modest increase in MVO2, Primarily by an increase in end-systolic wall stress.