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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.

BACKGROUND: We have previously reported our 3-step repair for obstructive hypertrophic cardiomyopathy (HCM) consisting of resection of the septum, horizontal plication of the anterior mitral leaflet (AML), and release of abnormal papillary muscle attachments. This article reviews our complete experience with surgical management of HCM to better understand the role and relevance of mitral plication. METHODS: From 1997 to 2011, 132 patients with HCM underwent surgical treatment at our institution. Eighty-two patients (62%) received AML plication based on selection criteria and were classified as group A; patients in group B did not receive plication. All patients underwent preoperative and postoperative echocardiography. Long-term clinical follow-up was obtained by review of scheduled echocardiograms and direct patient interview. RESULTS: The average age of all patients was 55.5 years. Operative mortality was 0%. The mean left ventricular outflow tract (LVOT) gradient decreased from 118+/-41 mm Hg to 6+/-13 mm Hg (p<0.0001). Mean mitral regurgitation improved from 2.4+/-1.0 to 0.5+/-0.7 (p<0.0001). Postoperatively, 96.2% of patients had no residual systolic anterior motion (SAM). Significant improvements in heart failure classification and quality of life scores were noted for all patients. Comparison of groups A and B showed no statistically significant differences in outcomes, complications, or survival. Survival at 1, 5, and 10 years was 98%, 98%, and 92%, respectively. CONCLUSIONS: The heterogeneity of the pathologic process in HCM supports detailed analysis of the septum, mitral leaflets, and subvalvular apparatus. Surgical management of HCM that includes horizontal plication of a lax and elongated AML is safe and results in durable clinical and echocardiographic improvement.

Unique genetic characteristics of hypertrophic cardiomyopathy (HCM), including heterogeneity and incomplete penetrance, have made making predictions about prognosis complex. We reviewed data from septal myectomy results as published from 1980 to 2011, most of which come from specialized tertiary care centers. We also performed a retrospective review of 132 consecutive patients who underwent HCM surgery at our institution. At a mean follow-up of 4.2 +/- 3.2 years (range, 3 days to 14.2 years), there were no deaths within 30 days of surgery for our cohort. Over the course of 15 years, 2 deaths occurred in older patients, both of whom had surgery for HCM along with additional cardiac procedures. Age, the presence of comorbidities, and concomitant cardiac procedures were not statistically significant risk factors for mortality. Overall survival at 1, 5, and 10 years was excellent: 99%, 99%, and 92%, respectively. Surgical myectomy has been proven to be a safe and effective procedure for symptomatic obstructive HCM, and it confers excellent survival similar to that of the healthy population.

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.

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.

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.