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Pharmacologic therapy is the first line approach to relieve symptoms in obstructive hypertrophic cardiomyopathy. There are no randomized trials to evaluate their effect on prognosis. Gradient reduction by surgical septal myectomy is associated with excellent prognosis, but not all patients have symptoms severe enough to require surgery; and, guidelines recommend operation only for patients with high gradients and symptoms unresponsive to pharmacologic therapy. The combination of disopyramide and beta-blockade is effective in reducing resting gradients (though not to the extent of surgery). This review examines the question of whether pharmacologic reduction of gradient in asymptomatic patients or those with milder symptoms might decrease HCM-related mortality.

Hypertrophic cardiomyopathy (HCM) occurs in 1 in 500 individuals. Treatment options for HCM differ from those administered in coronary disease, heart failure, and valvular disease patients that comprise the core of many cardiology practices. In this article, we offer a concise summary of the therapeutic use of disopyramide for reducing gradients and relieving symptoms in obstructive HCM.

Treatments for hypertrophic cardiomyopathy are largely selected based on patient symptoms and echocardiographic findings. Moreover, all the advanced treatments for heart failure symptoms depend on such imaging for planning and monitoring response to therapy. Risk of sudden death correlates with maximum left ventricular (LV) wall thickness. Massive LV thickening of 30 mm or more is an indication for primary prevention of sudden death with an implanted defibrillator. In this review, we will underscore potential pitfalls in echocardiographic diagnosis. Also we will review, a newly appreciated pathophysiologic mechanism in obstruction dynamic systolic dysfunction due to gradient.

A 70-year-old male with known hypertrophic cardiomyopathy (HCM) and latent obstruction presented with new onset of cardiogenic shock. He had a new resting left ventricular (LV) outflow gradient of 90 mmHg, and new severe LV systolic dysfunction. Because of rapid deterioration despite medical management he was urgently sent for surgical relief of obstruction, which immediately reversed both the LV dysfunction and shock. A second patient, a 58-year-old male also with hypertrophic cardiomyopathy and latent obstruction presented with collapse, cardiogenic shock, 135 mmHg resting LV outflow gradient and new severe LV systolic dysfunction. His profound shock was irreversible with pharmacologic management, but surgical relief of obstruction reversed both his LV dysfunction and shock. Echocardiography plays a pivotal role in the management of these acutely ill patients.

BACKGROUND: The ideal provocative maneuver in patients with hypertrophic cardiomyopathy (HCM) is a subject of ongoing investigation. Standing is a fundamental activity of daily life. This study examined acquisition of standing, Valsalva, and post-exercise left ventricular outflow tract gradients in HCM. METHODS: Rest supine, standing, and post-Valsalva gradients were measured in 98 consecutive patients with HCM who were referred for outpatient echocardiography. In 53 (54%) of the 98 patients, symptom-limited treadmill exercise was also performed, with gradients measured immediately after in the supine position. RESULTS: Fifty-six (57%) of the 98 patients had resting gradient<30 mm Hg and would thus be characterized as nonobstructive at rest. In the 98 patients, median gradients were 25 mm Hg at rest (range 0-205 mm Hg), increasing to 44 mm Hg after standing (range 0-309 mm Hg), an increase of 76%, and were again higher after Valsalva, 64 mm Hg (range 0-256 mm Hg) (P<.001). In the 53 patients who had gradient assessed after exercise, they were higher still, 100 mm Hg (range 0-256 mm Hg) (P<.001). In 29 patients (30%), standing provoked a higher gradient than Valsalva. CONCLUSION: Although standing increased gradients by 76%, it is not as potent a provocative maneuver as Valsalva or treadmill exercise. Nevertheless, standing is recommended as a physiologic provocative maneuver. In some patients standing may guide therapy; in others, the standing and exercise gradient provide a correct appreciation of the range of physiologically experienced gradients during daily upright activity.

Few other diseases show the degree of phenotypic heterogeneity expressed by HC. The two novel patients reported here with isolated posterobasal LV free wall hypertrophy (and mitral valve prolapse) extend this morphologic diversity even farther, now 3 decades after the introduction of contemporary 2-dimensional imaging.

This study examines acute effect of dual-chamber (DDD) pacing combined with disopyramide for left ventricular outflow tract (LVOT) gradient reduction in obstructive hypertrophic cardiomyopathy (HCM) patients. Among 24 patients refractory to maximal drug therapy, 7 had a significant improvement of LVOT gradient by DDD pacing alone. In the remaining 17 patients, the LVOT gradient reduction was 26+/-19% after DDD pacing alone and 35+/-16% after intravenous disopyramide alone. In contrast, after the combined therapy of DDD pacing and disopyramide, pressure gradient decreased from 102+/-35 to 28+/-23 mm Hg, a reduction of 72+/-21%. We have demonstrated synergy between DDD pacing and disopyramide for LVOT gradient reduction in obstructive HCM. Study of the long-term effects of this combined therapy would be the next step to ascertain clinical utility.