A Case Report of Hypertrophic Obstructive Cardiomyopathy UsingShort-term Temporary Pacing in the Evaluation of a Non-responder forPacing Therapy

Dual-chamber (DDD) pacing is a therapeutic strategy for hypertrophic obstructive cardiomyopathy (HOCM), but some patients show deterioration after implantation of the DDD pacemaker. We report a case of HOCM with shortness of breath upon physical exertion. To evaluate the suitability of pacing therapy, the acute effects of DDD pacing and short-term results using temporary VDD pacing were examined. The acute study demonstrated a mild reduction in the pressure gradient within the left ventricle. After 1 week of VDD pacing, a left ventriculography showed apical dyskinesis, with no effect on subjective symptoms or the blood concentration of brain natriuretic peptide (BNP) observed. Newly developed asynergy may be caused by changes in the contractile pattern. The patient underwent a myotomy-myectomy. After the operation, her subjective symptoms disappeared, and the hemodynamic parameters and blood concentration of BNP improved compared with those before the operation. The response to 1-week temporary VDD pacing can provide valuable data such as hemodynamics and neurohormonal changes in distinguishing between responders and nonresponders for pacing therapy.