Faculty Bibliography

BACKGROUND: We analyzed the clinical and quantitative echocardiographic characteristics of patients with sub-basal hypertrophic cardiomyopathy (HCM) to define the characteristics of patients (pts) with severe symptoms. METHODS: Of 444 pts in a referral-based HCM program, 22 (5%) had midventricular or apical HCM. Quality of life (QoL) questionnaire was administered as an independent confirmer of symptomatic state. RESULTS: Ten pts were NYHA III and IV, and 12 pts were NYHA I and II; QoL scores (41 +/- 26 vs. 10 +/- 13, P = 0.001) confirmed a priori division of two groups based on NYHA classification. Pts with more severe symptoms were more likely female (70% vs. 25%, P = 0.001) with atrial fibrillation (40% vs. 0%, P = 0.02). They more frequently had midventricular HCM 60% versus 8% (P = 0.01) (mid-LV thickness 17 +/- 6 vs. 12 +/- 2 mm, P = 0.03) and had much smaller LV diastolic volumes 68 +/- 12 versus 102 +/- 22 ml (39 +/- 4 vs. 53 +/- 12 ml/m(2), P = 0.001). Septal E/E' was higher in the severely symptomatic pts (15 +/- 5 vs. 7 +/- 3, P = 0.001) indicating higher estimated LV filling pressure. Midobstruction with apical akinetic chamber was noted in 4/10 pts who developed refractory symptoms. Cardiac mortality was higher in the severely symptomatic patients, 4/10 who had midventricular HCM as compared to 0/12 in the mildly symptomatic apical HCM group (P = 0.03). CONCLUSIONS: In subbasal HCM, pts with severe symptoms have midventricular hypertrophy, with encroachment of the LV cavity and consequent very small LV volumes that may be complicated by mid-LV obstruction. Pts with mid-LV hypertrophy are more symptomatic than those with apical HCM, are often refractory to therapy, and have higher mortality.

The shape of Doppler velocity tracings in obstructive hypertrophic cardiomyopathy offers insights into its pathophysiology. Inflection points are the points on a curve where its shape changes from concave to convex, or vice versa. These dynamic systolic abnormalities are caused: 1) by the amplifying nature of the obstruction; and 2) by the adverse effect of the sudden imposition of afterload in midsystole. The midsystolic drop in left ventricular ejection velocities and the premature termination of longitudinal shortening are compelling evidence of the deleterious mechanical effect of obstruction on the ventricle. This dynamic systolic dysfunction, demonstrated on the Doppler curves, may contribute to heart failure symptoms and adverse outcome. In outflow obstruction, these abnormalities normalize after abolition of gradient. Therefore, their detection in an individual patient confirms obstruction as a therapeutic target.

AIMS: A transthoracic echocardiographic (TTE) parameter that would stratify atrial fibrillation (AF) risk would be useful. Tissue Doppler imaging can quantify left atrial appendage contraction velocity (LAA A(M)). METHODS AND RESULTS: We studied 141 patients referred for transoesophageal echocardiogram (TEE); 48 were in AF. We obtained TEE and TTE LAA A(M) velocities from the LAA apex on the parasternal short-axis and apical two-chamber views. Adequate traces were obtained in 118 patients (84%). In these patients, we measured 5382 LAA A(M) velocity tracings. There was a strong correlation between LAA A(M) on TEE and TTE parasternal short-axis (r = 0.741; P < 0.0001) and apical two-chamber views (r = 0.729; P < 0.0001). Patients in AF had lower LAA A(M) than those with sinus rhythm on parasternal short-axis (12 +/- 5 vs. 23 +/- 7 cm/s, P < 0.0001) and apical two-chamber (14 +/- 5 vs. 23 +/- 8 cm/s, P < 0.0001) views. On parasternal short axis, LAA A(M) velocities were lower in patients with spontaneous echo contrast, 11 +/- 4 vs. 22 +/- 8 cm/s (P < 0.0001), and in those with thrombus, 8 +/- 2 cm/s (P < 0.0001). On apical two-chamber, LAA A(M) velocities were also lower with spontaneous echo contrast, 12 +/- 4 vs. 22 +/- 7 cm/s (P < 0.0001), and with thrombus, 10 +/- 4 cm/s (P < 0.0001). In patients with AF and TTE LAA A(M) < or =11 cm/s, we found that nearly one-third had LAA thrombus. In patients with AF and a history of stroke or transient ischaemic attack (TIA), LAA A(M) velocities were lower compared with those without history of stroke or TIA in the parasternal short-axis (9 +/- 3 vs. 13 +/- 5 cm/s, P = 0.02) and apical two-chamber views (11 +/- 3 vs. 15 +/- 6 cm/s, P = 0.008). CONCLUSION: Acquiring and quantifying LAA A(M) contraction velocity is feasible on TTE in a high percentage of patients and correlates with TEE. LAA A(M) was lower in AF compared with sinus rhythm, with spontaneous echo contrast compared to without spontaneous echo contrast, and in AF patients with a history of stroke or TIA. Those with LAA thrombus had the lowest LAA A(M) velocities. LAA A(M) is a novel functional parameter that may prove useful for risk stratification of AF

It is now 50 years since the modern description of hypertrophic cardiomyopathy (HCM). The initial descriptions foretold the current efforts towards sudden death prevention, alleviation of heart failure symptoms and angina, relief of left ventricular outflow tract obstruction, preparticipation athletic screening, family screening and genetic testing. The authors review the salient features of HCM, focusing on therapeutic strategies to manage its symptoms and attempts to prevent sudden death.

BACKGROUND: Abnormal positioning and size of the mitral valve contribute to the systolic anterior motion and mitral-septal contact that are important components of obstructive hypertrophic cardiomyopathy (HCM). The RPR repair (resection of the septum, plication of the anterior leaflet, and release of papillary muscle attachments) addresses all aspects of this complex pathology. This study reports outcomes regarding effectiveness of the RPR repair. METHODS: Fifty consecutive unselected patients (average age, 55.8 years) undergoing RPR repair for obstructive HCM from 1997 to 2007 were studied. Each patient underwent preoperative and postoperative transthoracic echocardiograms to document gradient, ejection fraction, degree of mitral regurgitation, and systolic anterior motion. Intraoperative transesophageal echocardiogram was used to guide all surgical repairs. Clinical follow-up included patient interviews to determine New York Heart Association (NYHA) status. RESULTS: Concomitant operations were performed in 25 patients (50%). Postoperative mortality was 0%. Average mean left ventricular outflow tract gradients decreased from 134 +/- 40 to 2.8 +/- 8.0. Mitral regurgitation improved from a mean of 2.5 to 0.1 (p < 0.001). Average length of stay was 6.9 +/- 2.7 days. NYHA class improved from 3.0 +/- 0.6 to 1.2 +/- 0.5. Follow-up was 100%, with a mean of 2.5 +/- 1.8 years. Average mitral regurgitation at follow-up was 0.9, with no residual systolic anterior motion. CONCLUSIONS: The RPR repair is safe and effective for symptomatic obstructive HCM. Our data support repair of the mitral valve that results in good intermediate outcomes with respect to gradient, mitral regurgitation, and clinical status.

The clinical use of the implantable cardioverter-defibrillator (ICD) is well established to prevent sudden death in patients with left ventricular dysfunction due to coronary artery disease and dilated cardiomyopathy, and its use has saved thousands of lives. More recently, its use has been extended to other patients at risk for sudden cardiac arrest due to ventricular fibrillation: patients with structural heart diseases such as hypertrophic cardiomyopathy and arrhythmogenic right ventricular dysplasia and patients with normal cardiac anatomy and function except for electrophysiologic abnormalities that predispose to cardiac arrest: Brugada syndrome and long QT syndrome. A distinguishing feature of these patients may be the young age when they present for either primary or secondary prevention. This contrasts with the "first wave" of adult ICD implantations that were usually performed in elderly or middle aged patients. An important consideration in favor of ICD implantation in young patients with sudden death risk is the long and cumulative period of their risk. Similarly, after implantation, these patients will experience the long-term risks of ICD implantation. This review focuses on the unique challenges presented by device implantation in young patients 16 to 45 years of age who may have 4 to 7 decades of life with their devices. Although devices may prolong life, they come with problems that will pose unique challenges for both patients and their physicians. Moreover, because of the long durations, these problems may accelerate as patients age.

When severe COPD and obstructive hypertrophic cardiomyopathy (HCM) coexist, management is challenging and complex. Drug contraindications limit pharmacologic options. Patients may not be candidates for surgical septal myectomy due to severe pulmonary disease. We describe a case of an elderly woman with severe reactive COPD who presented with an infectious exacerbation and dyspnea that progressed to near intubation due to heart failure from coexistent obstructive HCM. Transthoracic echocardiography revealed massive asymmetric septal hypertrophy and a diffusely hyperkinetic left ventricle with a left ventricular outflow tract (LVOT) gradient of 92 mm Hg. Two and a half hours after oral administration of disopyramide, LVOT gradient had decreased to 25 mm Hg with a corresponding immediate improvement in symptoms.