Theoretical considerations on the electrocardiogram of ventricular hypertrophy.

The electrical effect of ventricular hypertrophy is evaluated with an idealized model. Perfectly symmetrical hypertrophy is expected to enlarge the QRS complex with a certain proportion of the amplitude and duration. If the conduction velocity is unaltered, the QRS area will be increased proportionally to the myocardial mass. 2) Based on the preservation of the ventricular gradient, the secondary T change is expressed as a function of the QRS and G vectors. A theoretically interesting parameter, G/QRS ratio, is defined as a measure of the "ventricular gradient density," which is important for the over-all recovery pattern. This ratio is decreased in ventricular hypertrophy and is closely related to the QRS-T angle. 3) From the viewpoint of the theory, clinical cases with left ventricular hypertrophy are examined. The theory describes the cases with uncompicated hypertension fairly well, although variations from case to case are not small. Underlying assumptions and causes of deviations in actual cases are discussed.