The Influence of Aging of Various Diseases on the A-V Conduction Time

The P-Q interval of the Ecg was measured in 6, 289 consecutive patients admitted into the 2nd Department of Internal Medicine, University of Tokyo during a period of 1958 to 1970. The effect of aging of underlying diseases was examined and following results were obtained. 1) In male patients, the average value of the P-Q interval was 0.155″ in the second decade and was increased with age up to 0.179″ in the eighth decade. The difference between the 3rd or forth decade and seventh or eighth decade was statistically significant. In female cases, the average PQ interval was shorter than that of male cases and the P-Q prolongation with age was found after the seventh decade but was not significant below the age of 60. 2) The average PQ interval was longer in cardiac patients than in non-cardiac patients of the same age group. The difference was statistically significant with most of the groups with cardiac diseases. 3) The association Co-existence of the findings suggestive of ischemic heart disease, such as LAD, R-BBB & ST-depression, with the prolongation of the P-Q interval was found to be significantly frequent. 4) Cases with prolonged P-Q interval was more frequently found in anterior than in posterior infarction. However, the severity of clinical conditions and the age of the patients appeared to be more important factors for the PQ prolongation.