원발성 비후형 심근증에서 심근비후 형태에 따른 임상상의 차이 = Clinical Significance of the Patterns of Left Ventricular Hypertrophy in Idiopathic Hypertrophic Cardiomyopathy

다국어 초록 (Multilingual Abstract)

Background; The idipathic hypertrophic cardiomyopathy(HCM) is characterized by inappropriate myocardial hypertrophy of unknown cause. It may presents a variety of clinical and morphologic features according to the site and extent of the hypertrophy. The widespread application of echocardiography has made it possible to diagnose HCM earlier and easier, even in asymptomatic patients. However, clinical reports on the relationship between the distribution of left ventricular hypertrophy (LVH) and the clinical features are few in Korea. Therefore, the present clinical stu4y was performed to characterize more completely the distribution of LVH and to determine whether different patterns of hypertrophy are of particular clinical significance. Methods: The clinical, electrocardiographic and echocardiographic features were reviewed in 32 patients with idipathic HCM of Chonnam National University Hospital from July 1983 to August 1992. Results: 1) There were 23 males and 9 females. The mean age was 45.4±16.5 ranging from 15 to 74 years. There were no significant difference in age distribution according to the patterns of LUH. 2) Based on M-mode and 2-dimensional echocardiographic findings. The 32 patients were divided into 2 groups; 16 patients in the obstructive HCM group and the other 16 patients in the non-obstructive HCM group. Among the 16 patients with non-obstructive HCM, there were 6 patients with asymmetric septal hypertrophy(septal HCM), 7 patients with apical hypertrophy (apical HCM), 3 patients with symmetric (concentric) hypertrophy (symmetric or concentric HCM). 3) The cardinal clinical symptoms were dyspnea (71.9%), chest pain (59.5%), palpitation(37.5%) and syncope (12.5%). There were no significant difference in the frequency of symptoms according to the patterns of LCH. 4) On chest X-ray examination, the enlargement of cardiac silhoutte (C/T ratiok≥0.55) was observed in 32% of the cases. There wedre 4 patients with C/T ratio ≥0.6, and all had obstructive HCM. 5) In conventional 12 leads electrocardiograms, abnormal electrocardiographic findings were obtained in 94% of the cases. Among them repolarization abnormalities and left ventricular hypertrophy were most common, occuring in 80.6% and 64.5%, respectively. This was followed by abnormal Q waves (37.5%), atrial fibrillation (29.0%) and giant T wave inversion (29.0%). Giant T wave inversion was significantly more common in patients with apical HCM than in any other patients. 6) On the M-mode echocardiograms, the ratio of left ventricular septal thickness to left ventricular posterior wall thickness (IVS/LVPW) was 1.58±0.36 in obstructive HCM, 1.55±0.08 in septal HCM, 1.05±0.14 in apical HCM, and 1.13±0.08 in symmetric HCM. 7) On the 2-dimensional echocardiograms, the ventricular septum and anterolateral free wall were significantly thicker compared to left ventricular posterior wall in patients with obstructive and septal HCM (p<0.001, p<0.01 respectively). The apical wall was significantly thicker compared to the other regions in patients with apical HCM. 8) Mital regurgitation was detected by Doppler echocardiography in 13 (40.6%) of the total 32 cases of HCM and especially in 11 (68.8%) of the 16 cases with obstructive HCM. 9) Continuous wave Doppler echocardiography of left ventricular outflow tract was performed in 10 patients with obstructive HCM and revealed a mean peak pressure gradient of 50.1±39.9mmHg (13~130mmHg) between the left ventricular (LV) mid cavity and the LV outflow tract. Conclusion: Clinical features are very similar in every pattterns of LVH. But the above results suggested that depending on the extent and distribution of LVH, the functional and morphologic features of HCM may differ considerably. It is still questionable whether identifiable patterns of hypertrophy are of clinical significance.