Contrast-Enhanced Echocardiography for the Diagnosis of Apical Hypertrophic Cardiomyopathy

Apical hypertrophic cardiomyopathy presenting as recurrent unexplained syncope

Apical hypertrophic cardiomyopathy (AHC) is a rare variant of hypertrophic cardiomyopathy. Since its description by Sakamoto in 1976 in Japanese patients, our understanding of this entity has evolved. Although cardiac magnetic resonance imaging has emerged as the gold standard for diagnosing AHC, clinical attention must be drawn to the unique electrocardiographic features that provide the initial clues to making the diagnosis. In this case, we present a 47-year-old man with AHC who presented with recurrent syncope, but anomalies on his electrocardiogram went unnoticed on two clinical encounters. He was subsequently admitted to our service and rapidly diagnosed after we observed the very classical findings in the plain twelve lead electrocardiogram done at the time of admission. In a clinical encounter involving a patient presenting with recurrent syncope, special attention must be focused on the electrocardiogram to decipher the unique diagnostic features it might show.

Two hundred eight patients with apical hypertrophic cardiomyopathy in china: clinical feature, prognosis, and comparison of pure and mixed forms

BACKGROUND

Apical hypertrophic cardiomyopathy (AHCM) is a relatively rare form of hypertrophic cardiomyopathy (HCM), originally described in Japan and later in the West. Limited information is available on this disease in China.

HYPOTHESIS

This study was designed to describe clinical features and prognoses of patients with AHCM in China.

METHODS

A retrospective study of 208 consecutive patients with AHCM examined at FuWai Hospital was performed. Clinical features, mortality, and cardiovascular morbidity were analyzed.

RESULTS

The 208 patients with AHCM represented 16.0% of all HCM patients. Among them, 64.4% were pure form and 35.6% were mixed form. Compared with the pure group, the mixed group had a significantly larger left atrial diameter and thicker apical thickness. One hundred ninety-nine patients had a mean follow-up of 8.0 ± 3.5 years, cardiovascular mortality was 1.0%, and annual cardiovascular mortality was 0.1%. The 2 cardiovascular deaths were both mixed form. The probability of survival was 97.0 ± 2% at 10 years. Of the patients, 17.8% had 1 or more cardiovascular events. The probability of survival without morbid events at 10 years was 77 ± 4%. Three independent predictors of cardiovascular morbidity were identified: age at diagnosis ≥60 years, left atrial diameter ≥36 mm, and New York Heart Association class ≥III at baseline.

CONCLUSIONS

The prevalence of AHCM is relatively high, and it has a benign prognosis in China. However, 17.8% of patients may develop cardiovascular events. It is important to distinguish the 2 phenotypes of AHCM; the mixed form is less common but more serious than the pure form.

Incidental detection of apical hypertrophic cardiomyopathy by myocardial perfusion imaging

BACKGROUND

Echocardiography plays a central role in the diagnosis of hypertrophic cardiomyopathy (HCM). However, apical involvement of HCM may be missed because of foreshortening and inadequate clinical suspicion. These patients may be referred for single-photon emission computed tomography imaging.

METHODS

We present three cases of HCM predominantly involving the cardiac apex, whose diagnosis was first suspected on myocardial perfusion imaging. These patients were referred for chest pain syndromes to exclude significant coronary artery disease. All were undiagnosed on initial routine transthoracic echocardiography, and none were specifically suspected by the referring clinicians. All cases underwent an adenosine stress rest technetium-99m tetrofosmin myocardial perfusion protocol, and were subsequently referred for transpulmonary contrast echocardiography.

RESULTS

Single-photon emission computed tomography imaging revealed increased tracer uptake in all cases, most marked in the apical myocardium. Inferior wall ischaemia was detected in one case, consistent with a coronary stenosis seen at angiography. Apical hypokinesia was noted in two patients on gated studies. Contrast echocardiography confirmed the diagnosis of HCM with apical involvement in all cases.

CONCLUSION

Echocardiography is the first-line imaging technique for the diagnosis of HCM, but apical involvement may be missed unless a contrast study is performed. The presence of increased apical tracer uptake on perfusion imaging should alert the referring physician to the possibility of apical HCM, irrespective of earlier echocardiographic findings.

Utility of tissue characterization in apical hypertrophic cardiomyopathy diagnosis

A 60-year-old male with previous hypertension, left ventricle hypertrophy, and coronary artery disease was referred for stress echocardiography because of exertional chest pain. The electrocardiogram revealed deep T-wave inversion in the anterolateral leads. Contrast echocardiography was notable for an apical filling defect consistent with the apical form of hypertrophic cardiomyopathy. Cardiac magnetic resonance demonstrated the 'ace of spades' left ventricle cavity, confirming the diagnosis. Single photon emission computed tomography showed increased apical left ventricle tracer uptake. Velocity vector imaging study depicted lower than normal absolute maximal longitudinal tissue velocities. The apical longitudinal strain was negative without base to apex gradient. There were normal longitudinal strain values in the basal and mid myocardial segments (Figure 1). Apical hypertrophic cardiomyopathy is a rare condition occasionally missed by conventional echocardiographic studies. Intravenous contrast enhancement might improve diagnosis accuracy. Newer Doppler-based techniques allowing tissue characterization may complement contrast echocardiography in its diagnosis.