Faculty Bibliography

All patients with hypertrophic cardiomyopathy (HCM) should have five aspects of care addressed. An attempt should be made to detect the presence or absence of risk factors for sudden arrhythmic death. If the patient appears to be at high risk, discussion of the benefits and risks of ICD are indicated, and many such patients will be implanted. Symptoms are appraised and treated. Bacterial endocarditis prophylaxis is recommended. Patients are advised to avoid athletic competition and extremes of physical exertion. First degree family members should be screened with echocardiography and ECG.

This report describes a patient with an unusual large anomalous papillary muscle within the left ventricular cavity causing symptomatic midventricular outflow obstruction. The obstructing papillary muscle comprised a large central core that extended multiple circumferential muscular arms to all the walls of the left ventricle, including the septum. The papillary muscle and the arms divided the left ventricle into apical and subaortic chambers. Flow communicated between the two chambers through multiple openings between the arms with a systolic peak Doppler gradient of 50 mm Hg.

BACKGROUND: Extended myectomy for left ventricular outflow tract obstruction (LVOTO) due to hypertrophic cardiomyopathy (HCM) has good long-term results. In addition to the midseptal resection (R) for HCM, our group has introduced a novel variation in anterior leaflet plication (P) and release (R) of papillary muscle attachments. We sought to investigate the medium-term success of this three-step repair that addresses all aspects of complex HCM pathology. METHODS: Nineteen patients underwent resection-plication-release repair for complex HCM pathology. Transesophageal echocardiography was performed on all patients preoperatively and postoperatively to assess adequacy of resection, left ventricular outflow tract gradients, and mitral valve function. All patients underwent transthoracic outpatient echocardiography at a mean follow-up of 2.4 +/- 2.1 years (range, 0.5 to 6). RESULTS: The average age of the patients was 57 +/- 14 years. The preoperative peak LVOTO was 137 +/- 45 mm Hg. The average degree of mitral regurgitation was 3.1. The average length of stay was 7.5 +/- 3.3 days. There were no readmissions or deaths in the group. Initial postoperative transesophageal echocardiography demonstrated marked reduction in LVOTO to 10 +/- 17 mm Hg (p < 0.0001) and significant improvement in mitral regurgitation to 0.2 (p < 0.0001). In follow-up, the LVOT gradient remained low at 6 +/- 14 (p > 0.0001) and mitral regurgitation remained insignificant at 0.4 (p < 0.0001). CONCLUSIONS: Anterior leaflet plication and papillary muscle release are logical adjuncts to septal resection in the treatment of the complicated pathophysiology of obstructive HCM. Durable long-term results can be achieved with an aggressive approach to mitral valve pathology in conjunction with extended myectomy.

OBJECTIVES: In this study we assessed the long-term efficacy and safety of disopyramide for patients with obstructive hypertrophic cardiomyopathy (HCM). BACKGROUND: It has been reported that disopyramide may reduce left ventricular outflow gradient and improve symptoms in patients with HCM. However, long-term efficacy and safety of disopyramide has not been shown in a large cohort. METHODS: Clinical and echocardiographic data were evaluated in 118 obstructive HCM patients treated with disopyramide at 4 HCM treatment centers. Mortality in the disopyramide-treated patients was compared with 373 obstructive HCM patients not treated with disopyramide. RESULTS: Patients were followed with disopyramide for 3.1 +/- 2.6 years; dose 432 +/- 181 mg/day (97% also received beta-blockers). Seventy-eight patients (66%) were maintained with disopyramide without the necessity for major non-pharmacologic intervention with surgical myectomy, alcohol ablation, or pacing; outflow gradient at rest decreased from 75 +/- 33 to 40 +/- 32 mm Hg (p < 0.0001) and mean New York Heart Association functional class from 2.3 +/- 0.7 to 1.7 +/- 0.6 (p < 0.0001). Forty other patients (34%) could not be satisfactorily managed with disopyramide and required major invasive interventions because of inadequate symptom and gradient control or vagolytic side effects. All-cause annual cardiac death rate between disopyramide and non-disopyramide-treated patients did not differ significantly, 1.4% versus 2.6%/year (p = 0.07). There was also no difference in sudden death rate, 1.0%/year versus 1.8%/year (p = 0.08). CONCLUSIONS: Two-thirds of obstructed HCM patients treated with disopyramide could be managed medically with amelioration of symptoms and about 50% reduction in subaortic gradient over >/=3 years. Disopyramide therapy does not appear to be proarrhythmic in HCM and should be considered before proceeding to surgical myectomy or alternate strategies.

OBJECTIVES: The purpose of this study was to define appropriate parameters for risk stratification and prognosis in patients undergoing stress echocardiography. BACKGROUND: Stress echocardiography is an established technique for the diagnosis of coronary artery disease. However, current data on risk stratification of patients undergoing stress echocardiography are limited. METHODS: We evaluated 1,500 patients (59 +/- 13 years old; 51% male) undergoing stress echocardiography (34% with treadmill exercise and 66% with dobutamine). Resting left ventricular ejection fraction (EF) and regional wall motion were assessed by the consensus of two echocardiographers. Follow-up (mean 2.7 +/- 1.0 years) for confirmed non-fatal myocardial infarction (n = 31) and cardiac death (n = 44) were performed. RESULTS: By univariate analysis, both the peak wall motion score index (WMSI) (p < 0.0001) and EF (p < 0.0001) were significant predictors of cardiac events. Peak WMSI effectively risk stratified patients into low (0.9%/year), intermediate (3.1%/year), and high (5.2%/year) risk groups (p < 0.0001). A threshold of 45% EF provided further risk stratification of all WMSI groups. By multivariate logistic regression analysis, peak WMSI (relative risk [RR] 2.1, 95% confidence interval [CI] 1.0 to 4.4; p = 0.04) and EF (RR 1.0, 95% CI 0.9 to 1.0; p = 0.01) were both predictors of cardiac events. CONCLUSIONS: Stress echocardiography yields prognostic information for risk stratification of patients with known or suspected ischemic heart disease. A normal stress echocardiographic study (peak WMSI = 1.0) confers a benign prognosis (0.9%/year cardiac event rate). Peak WMSI >1.7 and EF < or =45% are independent markers of patients at high risk of an adverse clinical outcome.

BACKGROUND: Dobutamine-atropine stress echocardiography (DASE) is an established test for the diagnosis and risk stratification of patients with coronary artery disease. Atropine use to attain target heart rate prolongs test time. HYPOTHESIS: The aim of this study was to assess the utility of isometric handgrip exercise (33% maximal voluntary contraction x 4 min) with DASE. METHODS: We prospectively evaluated 131 patients undergoing DASE randomized to handgrip exercise or no handgrip. Effect of handgrip exercise on endpoints: time to target heart rate (85% maximum predicted), recovery time, total test time, mean dobutamine and atropine dosage, and the number of ischemic responses were assessed. Effect of current beta-blocker medication use was also evaluated. RESULTS: Heart rate rose more quickly in the handgrip group. At 6-10 min (peak handgrip), mean heart rate rose 51 +/- 14 beats/min in the handgrip group compared with 38 +/- 18 beats/min in the no handgrip group (p < 0.0001). With handgrip, overall dobutamine study time was reduced by a mean of 4.3 min (16.4 +/- 6.9 vs. 20.7 +/- 8.4, p = 0.004) in all patients, and by a mean of 5.9 min in patients not on beta-blocker medication (p = 0.001). The handgrip group also had a lower mean dose of dobutamine (25.8 +/- 13.5 vs. 32.4 +/- 16.4 mg, p = 0.025). The mean atropine dose was also lower (0.2 +/- 0.4 vs. 0.4 +/- 0.5 mg, p = 0.04). Handgrip exercise, however, did not decrease endpoints in patients on beta-blocker medication. CONCLUSIONS: Use of isometric handgrip exercise with DASE decreases time to target heart rate, recovery time, overall study time, and mean dosage of dobutamine and atropine. In patients not on beta-blocker medication, handgrip exercise should be routinely incorporated into all DASE protocols.

OBJECTIVES: The goal of this study was to determine the impact of race on identification of hypertrophic cardiomyopathy (HCM). BACKGROUND: Sudden death in young competitive athletes is due to a variety of cardiovascular diseases (CVDs) and, most commonly, HCM. These catastrophes have become an important issue for African Americans, although HCM has been previously regarded as rare in this segment of the U.S. population. METHODS: We studied the relationship of race to the prevalence of CVDs causing sudden death in our national athlete registry, and compared these findings with a representative multicenter hospital-based cohort of patients with HCM. RESULTS: Of 584 athlete deaths, 286 were documented to be due to CVD at ages 17 +/- 3 years; 156 (55%) were white, and 120 (42%) were African American. Most were male (90%), and 67% participated in basketball and football. Among the 286 cardiovascular deaths, most were due to HCM (n = 102; 36%) or anomalous coronary artery of wrong sinus origin (n = 37; 13%). Of the athletes who died of HCM, 42 (41%) were white, but 56 (55%) were African American. In contrast, of 1,986 clinically identified HCM patients, only 158 (8%) were African American (p < 0.001). CONCLUSIONS: In this autopsy series, HCM represented a common cause of sudden death in young and previously undiagnosed African American male athletes, in sharp contrast with the infrequent clinical identification of HCM in a hospital-based population (i.e., by seven-fold). This discrepancy suggests that many HCM cases go unrecognized in the African American community, underscoring the need for enhanced clinical recognition of HCM to create the opportunity for preventive measures to be employed in high-risk patients with this complex disease.