Ventricular tachycardia (VT) in dogs, detected by an ambulatory electrocardiograph attached for a duration, was analyzed, and life threatening factors were examined. Polymorphic and sustained VT were extremely at high risk. One half of the VT cases examined were died. It is important that arrhythmia must be treated immediately.
ECGs by standard limb leads and the chest lead (CV5RL lead) were simultaneously recorded in healthy 14 male (10-11 months old, weighing 7.42-10.70 kg) and 12 female (10-11 months old, weighing 5.54-7.40 kg) beagle dogs in the hanging position in slings without anesthesia. QT interval and the amplitude of T wave analyzed by the chest lead were compared with those from lead II. We concluded as follows: 1. The CV5RL lead gives constantly positive well defined T wave, and the amplitudes of T waves recorded by the lead were 1.7-7.5 folds larger than those recorded from lead II, whereas the patterns of T waves recorded from lead II were variable and were positive, negative, biphasic (negative followed by positive) and bifid (positive followed by positive). 2. The mean QT interval analyzed by the CV5RL lead was 4 msec (corresponded to 2% of the mean QT interval by lead II) longer than that analyzed by lead II. The 4 msec was considered to be incidental caused by the difference of the ECG leads. 3. Simultaneous ECG recording by standard limb lead (6 leads) and the CV5RL lead is not complicated, and the evaluation of QT interval by the CV5RL lead may be useful for the comparison of the intervals in same animal or other animals.
Pulmonary stenosis with intact ventricular septum was observed in 4 (0.6%) of 670 bovine hearts showing congenital cardiovascular anomalies. In cases 1 to 3 the hearts showed valvular pulmonary stenosis. In these hearts the annulus of the valve was narrowed by hypoplasia of the right semilunar valve and right sinus of pulmonary trunk. Case 3 showed fusion of the commissura between right and intermediate semilunar valves. Case 4 showed valvular, supravalvular and infundibular pulmonary stenosis. In this heart the annulus of the valve was narrowed, and hypoplasia of the pulmonary trunk and infundibulum was recognized.