Enhancing ventricular contractility by post-extra-systolic potentiation is useful for predicting projected aortic valve area in low-flow low-gradient aortic stenosis: a case report

Excerpt

A 71-year-old man was admitted to the hospital with dyspnea. Electrocardiography showed sinus rhythm with occasional ventricular premature contraction (VPC). Echocardiography showed a dilated left ventricle, an ejection fraction of 37%, and restricted mobility of the aortic valve due to calcification. The estimated aortic valve area (AVA) at the sinus beat was 0.80 cm² with a transaortic maximum velocity (max-V) of 3.0 m/s and transaortic flow rate of 162.1 mL/s (Fig. 1a, a’, d), suggesting low-flow low-gradient aortic stenosis (AS). In contrast, the estimated AVA at the beat immediately after VPC was 0.87 cm² with max-V of 3.5 m/s and increased transaortic flow rate of 220.5 mL/s (Fig. 1b, b’, d), indicating augmented contractility by post-extra-systolic potentiation (PESP). On dobutamine stress echocardiography (DSE), AVA was 0.92 cm² with max-V of 4.1 m/s and transaortic flow rate of 251.3 mL/s at a dose of 20 μg/kg/min (Fig. 1c, c’, d), indicating a diagnosis of true severe AS. Interestingly, two plots of the flow rate on AVA, two beats of sinus rhythm, and PESP were upon the regression line with the increasing dose of DSE (Fig. 1e). Accordingly, the projected AVA at a flow rate of 250 mL/s was predictable by DSE as well as PESP. The patient underwent surgical aortic valve replacement, followed by the recovery of ejection fraction from 37 to 47%.

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