Clinical profiles of hypertrophic cardiomyopathy with apical phenotype--comparison of pure-apical form and distal-dominant form.
BACKGROUND
Hypertrophic cardiomyopathy (HCM) with an apical phenotype, in which hypertrophy of the myocardium predominantly involves the apex of the left ventricle, is not uncommon in Japan, but its morphologic variations are not well recognized. The aim of this study was to investigate if these variations have different clinical characteristics although they are still confused to be the same.


RESULTS
Patients with the apical phenotype were divided into 2 groups, the "pure-apical" form and the "distal-dominant" form, and their clinical profiles were compared. From the study cohort of 264 patients with HCM, 80 (30%) were classified as having the apical phenotype: 51 with the pure-apical form and 29 with the distal-dominant form. The age at diagnosis was approximately 60 years, and in both groups the majority were male. The distal-dominant group had a significantly larger left atrial diameter (43 vs 39 mm) and higher ratio of proven familial HCM (28 vs 6%), and were more symptomatic (New York Heart Association >or=3) at presentation (17 vs 0%). The event-free rate of cardiovascular events in patients with the distal-dominant form was significantly worse (log-rank P=0.012) than that in patients with the pure-apical form (follow-up period: asymptotically approximately 5 years).


CONCLUSIONS
The 2 phenotypes of apical HCM should be recognized and distinguished clinically.
Kubo
Toru
T
Department of Medicine and Geriatrics, Kochi Medical School, Nankoku, Japan.
Kitaoka
Hiroaki
H
Okawa
Makoto
M
Hirota
Takayoshi
T
Hoshikawa
Eri
E
Hayato
Kayo
K
Yamasaki
Naohito
N
Matsumura
Yoshihisa
Y
Yabe
Toshikazu
T
Nishinaga
Masanori
M
Takata
Jun
J
Doi
Yoshinori L
YL
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000175:diagnosis / Q000208:ethnology / Q000401:mortality / Q000503:physiopathology; D024741:Cardiomyopathy, Hypertrophic, Familial / Q000150:complications / Q000175:diagnosis / Q000208:ethnology / Q000401:mortality / Q000503:physiopathology; D002648:Child; D018450:Disease Progression; D018572:Disease-Free Survival; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011379:Prognosis; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D055815:Young Adult