Significant myocardial pathology and increase of alpha 1-adrenergic receptor number affecting the arrhythmogenic condition in cases with ventricular tachycardia.
To study the pathogenesis of idiopathic ventricular tachycardia with left bundle branch block morphology (LBBB-VT), histopathological findings in 34 patients and adrenergic receptor (AR) density obtained by micro-autoradiography in 11 patients were analyzed, using endomyocardial biopsy samples. According to the ventricular volume, we divided the patients into 3 groups. Group A patients (n = 8) were diagnosed as having arrhythmogenic right ventricular dysplasia (ARVD) showing right ventricular enlargement, group B patients (n = 7) showed decreased left ventricular function and/or enlarged left ventricle, and group C (n = 19) included patients with idiopathic ventricular tachycardia (VT) without enlargement or dysfunction of either ventricle. Histologically, there was a high incidence of significant pathology showing myocardial hypertrophy, degeneration, abnormal branching, and interstitial fibrosis in all groups (group A, 100%; group B, 86%; group C, 56%). There was a higher incidence of fatty tissue infiltration in groups A (100%), B (71%), C (48%) than in the control groups. As for AR, specific grains of alpha 1- and beta-AR were 23.0, and 18.3 (grains/25 x 25 mm square) respectively, in patients with LBBB-VT. The number of alpha 1 grains in patients with LBBB-VT was apparently higher than in the control group, sick sinus syndrome (SSS; 11.2), and the beta-AR density in the LBBB-VT group was the same as in the control group (SSS; 15.4). We concluded that the significant pathology in cases with VT might affect the arrhythmogenic condition. Moreover, these results suggested that the increase in the number of alpha 1-AR might have a great influence in idiopathic VT.
Hasumi
M
M
Heart Institute of Japan, Tokyo Women's Medical College, Japan.
Hiroe
M
M
Fujita
N
N
Hasumi
S
S
Toyosaki
T
T
Nagao
H
H
Hosoda
S
S
Kasajima
T
T
Sekiguchi
M
M
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001345:Autoradiography; D001706:Biopsy; D002037:Bundle-Branch Block / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D011942:Receptors, Adrenergic, alpha / Q000032:analysis* / Q000502:physiology; D013610:Tachycardia / Q000473:pathology* / Q000503:physiopathology
D011942:Receptors, Adrenergic, alpha