CLINICAL STUDY ON SILENT MYOCARDIAL ISCHEMIA

• Published in: Japanese Journal of National Medical Services Vol. 47; no. 11; pp. 844 - 849
• Main Authors: TAMURA, Yoshiyuki, MIZUNUMA, Yoshiyuki, NAGASE, Norio, ISHIMOTO, Takeo, SAKO, Harunobu, KOBAYASHI, Kazuo, MORI, Kenichi, OKUMURA, Hironobu, KAWAGUCHI, Takashi
• Format: Journal Article
• Language: Japanese
• Published: Japanese Society of National Medical Services 1993; 一般社団法人 国立医療学会
• Subjects: Holter ECG; myocardial infarction; silent myocardial ischemia; ventricular premature contraction; ホルター心電図; 心室性期外収縮; 心筋梗塞; 無症候性心筋虚血
• DOI: 10.11261/iryo1946.47.844
• ISSN: 0021-1699

Attacks of myocardial ischemia without any symptoms are termed as silent myocardial ischemia (SMI). We studied the incidence of attacks and arrhythmias in 87 patients of SMI demonstrated on 24-hour electrocardiographic (Holter) monitoring. SMI patients were demonstrated in 3 groups by Cohn's report: type I; those totally asymptomatic (9 cases), type II; those after myocardial infarction (9 cases) and type III; those with angina pectoris (65 cases). The frequencies of SMI events on 24-hour Holter monitoring were as follows; one, from 2 to 4 and more than 5 times were 25 (30%), 46 (55%) and 12 cases (15%), respectively. The episodes of SMI occurred predominantly during the daytime hours; from 6:00am to 0:00pm and from 0:00pm to 6:00pm were 40% and 30%, respectively. At event time of SMI (44 events) sinus tachycardia, ventricular premature contractions (VPCs) and atrial fibrillation were found in 21 (48%), 4 (9%) and 1 event (2%), respectively. Incidences of VPCs for 24 hours of type I, II and III were 100, 78 and 69%, respectively and the greater part of VPCs was more than Lown's grade 3. Sixty-seven patients of SMI (7 for type I, 8 for type II and 52 for type III) were followed up for from 1.1 to 3.3 years (mean 2.4 years). Eleven (16.4%) died and of those patients, five (7.5%) were cardiac death (2 for type II and 3 for type III) . Four (6%) developed myocardial infarction (1 for type II and 3 for type III). Thus, patients with SMI had high incidences of arrhythmias and cardiac events.