Clinical Studies on the Ventricular Strain Pattern Electrocardioogram (II) : The Relationship between the Ventricular Strain Pattern ECG and the Coronary Insufficiency
1961 Volume 25 Issue 12 Pages 1287-1293
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1961 Volume 25 Issue 12 Pages 1287-1293
The relationship between the strain pattern ECG and the coronary insufficiency has been studied with various methods, such as by recording ECG by oesophageal leads or with the administration of amyl nitrite, O2 load or exercise load. The results were as follows : (1) Thirteen cases of left ventricular strain pattern and 4 cases of right ventricular strain pattern were subjected to the ECG recording from the oesophagus. Of 13 cases who gave the left ventricular strain pattern in chest leads, 5 cases(38.4%) gave the same ventricular strain pattern at the base and posterior wall of the left ventricle. In those who gave right ventricular strain pattern in chest leads normal T waves were recorded from the base of the left ventricle. (2) Amyl nitrite was administered to 11 cases with left ventricular strain pattern and 2 cases with right ventricular strain pattern in the form of inhalation of 0.25cc (5 drops) and ECG were recorded before, 6 minutes after and 12 minutes after, the inhalation. In the group of left ventricular strain pattern this maneuvre caused the T wave inversion and ST depression to become less pronounced, to some extent, than before in CR5 and CR6 in about 70% of the cases. On the contrary STII was depressed in 55% of the cases. (3) Four cases with left ventricular strain pattern and one case with right ventricular strain pattern were subjected to the O2 load, using a complete closed system, i.e., DaviesGilchrist mask, in dose of 3 liter per minute and for the period of 15 minutes ; ECG were recorded before, 1 minute after, 12 minutes after, and 12 minutes after the cessation of, the O2 load. T waves tended to become high in II, CR5 and CR(; by 0.18-0.01 mV ; ST segment was elevated in all cases in CR6, and in a half of case, in CR2 and II and by 0.06-0.01 mV. Twelve minutes after the cessation of the O2 load, R spike became, low, or tended to become low, ST segment depressed and T wave lowered. QTc was prolonged 12 minutes after the start of O2 load ; its change was not consistent one minutes after, or 12 minutes after the cessation of, O2 load. (4) Six cases with left ventricular strain pattern and 2 cases with right ventricular strain pattern were subjected to Master's exercise test in double dose ; ECG were recorded before, 3 minutes after, 10-12 minutes after, the exercise test. In the group of left ventricular strain pattern the T wave became low or more inverted than before in II, CR2 and CR6 in 70% of the cases each ; on the contrary the T wave in CR5 became less inverted than before in 85 % of the cases. The ST segment became more depressed than before in II, CR6 in 83.66% of the cases each ; changes in CR5 were diverse in direction. The magnitude of these changes was small in all cases. QTc was prolonged in 83% of the cases. (5) It is suggested from the above observations on ECG recorded from the oesophageal leads and with 3 types of loading tests (1) that the ventricular strain pattern ECG is closely related to the coronary insufficiency and (2) that such a coronary insufficiency depends much on the coronary factors and (3) that the observed facts can be beautifully explained by Prof. Maekawa's theory of "latent coronary insufficiency". (6) The author discussed various theories with reference to the genetic mechanism of the ventricular strain pattern ECG.
