engleski

Paradoxical base to apex gradient during IVRT in a HOCM patient with right ventricular pacing

Background Implantation of pacemaker is one therapeutical modality to reduce LVOT gradient in hypertrophic obstruction cardiomyopathy (HOCM). We present a case of reversal systolic to opposite IVRT mid-cavitary gradient due to the right ventricular pacing. Methods A 70 year old female with known HOCM, FA and DDD pacing (after AV nodal ablation) was admitted because of sudden pain in her left calf. Diagnostic evaluation revealed peripheral artery disease and ischemia due to thromboembolic event. Results Transthoracic echocardiography revealed asymmetric HOCM (septal thickness of 25 mm). Pulse Doppler detected abnormal mid-cavitary gradient (max PG 39 mmHg) directed from the LVbase to apex during isovolumic relaxation time (IVRT), simultaneously with the formation of small apical sequestration, while systolic LVOT gradient was 12 mmHg. Further, Doppler Myocardial Imaging Strain analyses revealed late systolic thickening of lateral wall lasting after aortic valve closure until apical relaxation. Echocardiogram before pacemaker implantation revealed resting systolic midcavitary gradient from apex to base of 40 mmHg. Conclusion Right ventricular pacing reduced LVOT gradient by altered LV electrical activation pattern, but as well induced base to apex IVRT gradient. Presumably, due to the delayed activation of lateral wall, mid-cavity obstruction appeared later on, during IVRT while at the same time, relaxation (initiated in the apex) formed small empty apical cavity. This in turn generated intracavitary reversal gradient followed by paradoxical flow across obstruction during IVRT.

right ventricular pacing; HOCM; intracavitary gradient; IVRT

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