Depolarization phase of the spatial velocity electrocardiogram in normal and ventricular overloading

Summary The depolarization phase of the spatial velocity electrocardiogram was studied in normal subjects and patients with right and left ventricular overloading, and significant differences were found among them. The normal pattern consists usually of four spikes, ξ, ϱ 1 , ϱ 2 and σ, and of three nadirs between them, ξ e , ϱ m and σ i , which showed common features as follows: 1/2 ϱ 2 ≤ ϱ 1 ≤ ϱ 2 , ϱ m ≥1/3 ϱ 1 , ξ≤1/3 ϱ 1 , ξ e ≥1/3 ξ, σ≤1/3 ϱ 2 , σ i ≥1/3 σ, ξϱσ duration ≤100 msec, interval between the peak of ϱ 1 and ϱ 2 ≤ 20 msec, ξ duration ≤20 msec, and σ duration≤40 msec. The spatial velocity electrocardiogram of left ventricular overloading showed one or more of the following features: ϱ 1 was larger than ϱ 2 , ϱ m was less than a third of ϱ 1 , splitting between ϱ 1 and ϱ 2 was deeper and wider than normal ranges, ϱ 1 showed splitting, or both ξ and σ were absent. Left ventricular volume overloading could be largely differentiated from left ventricular pressure overloading by a marked tendency of a deep ϱ m with a prolonged interval between the peak of ϱ 1 and ϱ 2 . In contrast the spatial velocity electrocardiogram of right ventricular overloading showed one or more of the following features: ϱ 1 was smaller than the half of ϱ 2 , σ was larger than a third of ϱ 2 , or splitting between ϱ 2 and σ was deeper and duration of σ was longer than normal ranges. Right ventricular volume overloading could be largely differentiated from right ventricular pressure overloading by a marked tendency of the deep σ i . with a prolonged duration of σ.