Doppler Systolic Signal Void in Hypertrophic Cardiomyopathy: Apical Aneurysm and Severe Obstruction without Elevated Intraventricular Velocities.

BACKGROUND: In patients with hypertrophic cardiomyopathy (HCM), akinetic apical aneurysms are associated with ventricular tachycardia, heart failure, apical thrombus, and mortality. The cause of apical aneurysms remains unresolved, and there is controversy about prevalence and significance of mid-left ventricular (LV) obstruction, often present in these patients. The aim of this study was to test the hypothesis that low velocities in patients with aneurysms are due to near complete cessation of mid-LV flow, characteristically marked by a Doppler signal void. METHODS: This was a retrospective analysis of 39 patients with HCM with segmental hypertrophy of the mid left ventricle and complete systolic emptying at the mid-LV level. The severity of dynamic obstruction was evaluated by measuring the time during which cross-sectional mid-LV cavity area was <1 cm(2). Presence or absence of an LV Doppler midsystolic signal void was determined. RESULTS: Akinetic apical aneurysms were present in 21 patients. The duration of two-dimensional mid-LV short-axis complete emptying was longer in patients with akinetic apical aneurysms (194 ± 45 vs 148 ± 63 msec, P = .013), nearly 50% of systole. Midsystolic signal voids were seen only in patients with akinetic apical aneurysms (P < .001), present in 86%. In patients with akinetic aneurysms, there was a strong correlation between the duration of the systolic signal void and the proportion of systole with complete emptying < 1 cm(2) (r = 0.704; P = .001). Complete emptying < 1 cm(2) for ≥ 38% of systole was associated with akinetic aneurysm (odds ratio, 9.35; P < .004). CONCLUSION: Patients with akinetic apical aneurysm HCM have near complete cessation of flow across severe dynamic mid-LV obstruction for nearly 50% of systole. This explains how the adverse effects of obstruction may occur without high velocities on echocardiography.

Symptomatic exercise-induced left ventricular outflow tract obstruction without left ventricular hypertrophy.

BACKGROUND: Left ventricular (LV) outflow tract obstruction (LVOTO) is most commonly seen in patients with hypertrophic cardiomyopathy. Postexercise dynamic LVOTO (DLVOTO) has been infrequently identified in symptomatic patients without LV hypertrophy, and its pathophysiology is not well established. The aim of this study was to identify echocardiographic abnormalities that might explain the dynamic development of systolic anterior motion, mitral-septal contact, and LVOTO in these patients. METHODS: Patients with DLVOTO and normal wall thickness were compared with 20 age-matched and gender-matched controls with normal stress echocardiographic findings. Two other groups were also compared: patients with DLVOTO and mild segmental hypertrophy (segmental wall thickness ≤15 mm) and patients with normal left ventricles but DLVOTO after dobutamine stress. RESULTS: Six symptomatic patients were identified (mean age, 48 ± 9 years; range, 37-60 years; five men) with normal wall thickness who developed DLVOTO after exercise during a 6-year period. Five had been hospitalized for cardiac symptoms. The mean postexercise LV outflow tract gradient caused by systolic anterior motion mitral-septal contact was 107 ± 55 mm Hg (range, 64-200 mm Hg). All patients had echocardiographic LV wall thicknesses in the normal range (≤12 mm). Structural abnormalities of the mitral valve were identified in all six patients. These were elongated posterior leaflets (2.0 vs 1.5 cm, P < .0005), elongated anterior leaflets (3.2 vs 2.6 cm, P = .015), increased protrusion height of the mitral valve beyond the mitral annular plane (2.6 vs 0.6 cm, P < .00001), and residual protruding portions of the mitral valve leaflets (0.85 vs 0.24 cm, P < .005). There was anterior positioning of the papillary muscles in the LV cavity, with a greater distance from the plane of the papillary muscles to the posterior wall (1.8 vs 1.3 cm, P = .03). In two patients, potentially provoking medications were stopped; two patients received ß-blockers, with reductions of angina. Medium-term prognosis was good; no patient had died after 3.5 years. The mitral valve abnormalities in the 10 patients with DLVOTO and mild segmental hypertrophy were qualitatively and quantitatively very similar to those in patients with DLVOTO without hypertrophy. In contrast, the valves of patients with dobutamine stress DLVOTO were not elongated, but 50% had residual mitral leaflets that protruded past the coaptation point by ≥5 mm. CONCLUSIONS: DLVOTO after exercise can occur in the absence of LV hypertrophy and may be associated with high gradients and cardiac symptoms. Elongated, redundant mitral valve leaflets with anterior position of the papillary muscles appear to cause the postexercise obstruction.

Assessment of left atrial appendage function with transthoracic tissue Doppler echocardiography.

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.