Masuji Seki

Significance of T-loop change in vectorcardiographic diagnosis of left ventricular hypertrophy

Abstract 1. 1. One hundred and seventy-five Frank lead vectorcardiograms of autopsy cases were reviewed in order to evaluate the significance of T-loop change in the diagnosis of left ventricular hypertrophy (LVH). 2. 2. The T loop was usually oriented to the left and inferiorly in the absence of LVH, whereas in the majority of the cases of LVH, whether associated or not with significant coronary sclerosis, the T loop was displaced to the right and anteriorly. A significant rightward displacement of the T loop was observed in 55.6 per cent of 36 cases of uncomplicated LVH and in 59.2 per cent of 49 cases of LVH associated with significant coronary sclerosis. The corresponding figures in the normal cases and in those with coronary sclerosis without LVH were 7.7 and 13.7 per cent, respectively. 3. 3. A T loop directed to the right and posteriorly was seen exclusively when significant coronary sclerosis was present in association with LVH. 4. 4. A displacement of the T loop to the right was considered to be a more sensitive and reliable sign of LVH than was formerly believed, and the maximum T angle was thought to be a better parameter for the diagnosis of LVH than the magnitude of the QRS vector. A possible clinical significance of posterior displacement of the T loop was also suggested.

Some Pitfalls of Vectorcardiographic Diagnosis of Myocardial Infarction with Particular Respect to Emphysema

Vectorcardiographic changes indicating old myocardial infarction were observed in eight of 288 patients who at autopsy did not show extensive myocardial disease. Of these eight patients four had been given a misdiagnosis of anteroseptal infarction, while four had been suspected of having anterolateral or anterior infarction on the basis of an abnormal configuration of the initial portion of the QRS loop. The possibility of overdiagnosis of myocardial infarction should be borne in mind in reading vectorcardiograms, especially in the absence of clear-cut history of the condition.A prominent Q wave simulating anteroseptal or anterior infarction was observed in lead V2 or V3, or in both in 12-lead electrocardiograms in all these eight cases. A high incidence of coronary sclerosis, scattered myocardial fibrosis and pulmonary emphysema was noted in these false positive cases at autopsy, but right ventricular hypertrophy, significant septal hypertrophy, or giant right atrium was not demonstrated.

QS-and QR-pattern in leads V3 and V4:electrocardiographic and pathologic correlation of 41 cases,including 25 cases without myocardial infarction.

Although a QS or QR pattern in leads V3 and V4 is generally accepted as a diagnostic sign of myocardial infarction, similar patterns are also found in cases without infarction. Among 41 autopsied cases with significant Q waves in leads V3 and V4 there were 25 not associated with myocardial infarction. These electrocardiographic abnormalities were rather frequently observed at terminal stage and also in cases with severe pulmonary emphysema. It is difficult to decide whether myocardial infarction is present when significant Q waves persist without any other definite signs and symptoms, although the presence of coronary T wave in a precordial lead and/or marked left axis deviation is suggestive of infarction. The cause of significant Q waves in the absence of myocardial infarction was discussed and altered position of the heart was suggested to be responsible.

Effect of Blood Pressure and Coronary Stenosis on Cardiac Hypertrophy

冠動脈狭窄・心筋虚血が心肥大発生の重要な因子となりうるか否かについて検討するため, 老年者連続剖検例418例の心剖検所見を分析した.当然予想されるように, 生前の血圧と心肥大との間には密接な関係があり, 最大血圧180mmHg以上または最小血圧100mmHg以上の群では心肥大を呈するものが過半数を占め, 心重量/身長比が2.0を越えるものは, それぞれ54.8%, 56.6%であった. また, 心筋に著明な虚血性病変のみられたものでは, 冠動脈狭窄度, 血圧値に関係なく心肥大例が多くみられた.これに反し, 心筋病変の著明なものをのぞくと, 冠動脈狭窄度と心肥大との関係は明らかではなく, 内腔面積の狭窄が75%以上の高度狭窄が2枝以上に存在するものにおいても心重量/身長比が2.0を越えるものは45.5%であり, この値と有意な冠狭窄のないものにおける33.7%との間には有意な差は認められなかった.以上の所見から, 冠動脈狭窄・心筋虚血は, 心筋に著明な病変を生じないかぎり心肥大成立の一義的な因子とは考えがたいと結論した. ただし, 高度高血圧例のみを取上げると, 高度冠硬化例に心肥大の多い傾向が認められており, 高度高血圧の存在下においては, 冠硬化の合併が心肥大の付加的因子となる可能性も否定できない.