Long-term evaluation of patients with apical hypertrophic cardiomyopathy

Apical hypertrophic cardiomyopathy (AHCM) is characterized by primary hypertrophy localized exclusively in the apex of the left ventricle. Previous studies have indicated that AHCM results in a unique combination of cross-sectional echocardiographic (CSE) and ECG findings (‘giant’ Twave inversion and high R wave voltage in the precordial leads). The aims of this study were: (1) to assess the degree of AHCM in a quantitative fashion (2) to evaluate the possible relationship between apical hypertrophy, quantitatively determined, and ECG findings in patients with AHCM (3) to verify the changes in echocardiographic and ECG parameters over time (4) to define the relationship between the severity of AHCM and the clinical course of such patients. Eleven selected patients with AHCM were studied for an average 6 year follow-up period; there were seven men and four women (age from 18 to 62 years, mean 49). Apical hypertrophy was assessed quantitatively by determining the muscle cross-sectional area in the apical region, which was considered an index of myocardial mass. From the end-diastolic apical four chamber view, endocardial and epicardial contours were digitized in order to obtain the total muscle cross-sectional area of the left ventricle. The walls of the left ventricle were then divided into three regions (basal, intermediate, apical). The final value of each cross-sectional muscle area was obtained from the mean measurements of four independent and blinded observers. In AHCM the apical muscle cross-sectional area (AMA) ranged from 10.3 to 17.9 cm2, mean 13.2 ±2.6 cm2. The comparison between CSE and ECG findings showed that patients with giant negative T wave inversions (T wave >10 mm) and high R wave voltages (R wave >25 mm) had a more severe degree of apical hypertrophy. However, there was incomplete agreement between CSE and ECG findings. During follow-up, negative T wave amplitude increased from 8.5 ±3.4 to 11.9 ±3.6 mm (mean 4.2 ±2.7) in 10 patients (P>0.01) and there was a mild increase of precordial R wave (from 28.0 ±5.9 to 29.3 ± 5.2 mm, mean 1.5 ± 1.6) (P−ns). The AMA change over time, from 13.2 ± 26 to 13.8 ± 2.3 was not significant. All patients were alive at the most recent evaluation, and witliout significant symptomatic deterioration. This study demonstrates a wide spectrum in the degree of severity of apical hypertrophy among patients with AHCM. Furthermore, ECG findings are not uniform and are not significantly related to the severity of the hypertrophy itself Therefore, AHCM should be considered as a part of the morphological spectrum of hypertrophic cardiomyopathy rather than a separate entity with univocal CSE and ECG findings. Follow-up data indicate that despite ECG results worsening over time, a significant progression in apical left ventricular wall thickness does not occur. Changes in negative T wave amplitude are not related to symptoms and are not predictive of the functional severity of AHCM. Finally, the clinical outcome of patients with AHCM seems not be dependent on the entity of apical hypertrophy.