Prevalence and significance of left ventricular outflow gradient during dobutamine echocardiography

Aims This study investigated the clinical and physiological significance of the dynamic left ventricle outflow gradient observed in some patients duri ng dobutamine stress echocardiography. Methods Three hundred and ninety-four consecutive patients completed dobuta mine stress echocardiography using Doppler echocardiography to assess the p resence of myocardial ischaemia and left ventricular outflow gradient. The prevalence of left ventricular outflow gradient was evaluated and correlate d with echocardiographic and clinical findings. Fifteen patients with left ventricular outflow gradient during dobutamine infusion underwent exercise echocardiography for appearance of left ventricular outflow gradient. Results Sixty-nine of 394 (17.5%) patients developed a left ventricular out flow gradient of more than 36 mmHg. In nine of them (13%) the anterior mitr al valve leaflet had a systolic anterior motion. In 60 of the 69 patients ( 87%) there was a dynamic obstruction at the level of the papillary muscles. The mean intracavitary gradient was 75.4 (range 36-175) mmHg. There was no correlation between the presence or absence of a dobutamine stress echocar diography-induced left ventricle outflow gradient and chest pain or shortne ss of breath. In patients who developed a left ventricular outflow gradient ischaemic wall motion abnormalities occurred at a significantly lower freq uency during dobutamine stress echocardiography (2.9 vs 16.4% P<0.001). Non e of the 15 patients who underwent exercise echocardiography developed sign ificant left ventricular outflow gradient. Conclusion Left ventricular outflow gradient occurs occasionally during dob utamine stress echocardiography examination. Its presence is of no physiolo gical or clinical significance.