Table 3 Abnormal electrocardiographic features in DNA-immunized dogs with experimental T. cruzi infection
GROUP | 3 MONTHS PI (t3 = ACUTE STAGE) | DOGS/n (%) | 6 MONTHS PI (t4 = CHRONIC STAGE) | DOGS/n (%) | ||
|---|---|---|---|---|---|---|
pBCSP | Long P wave (0.06 s vs. 0.04 s a), absence of some T waves, and tachycardia | Intraventricular conduction defects | 1/6 (17%) | MEAD to the left, tall R wave in CV6LL (3.0 mV vs. 2.5 mVa), R wave greater in lead I than leads III and aVF | Left ventricle enlargement | 1/6 (17%) |
Long P-R interval (0.14 s vs. 0.12 s a) | AV block | 1/6 (17%) | ||||
pBCSSP4 | Elevated S-T segment in leads I, III, aVF and CV6LL (0.5 mV vs. 0.2 mV a) | Myocardial infarction and/or pericarditis | 1/6 (17%) | Several absent P waves | Second-degree AV block | 1/6 (17%) |
Wide QRS complex (0.06 s vs. 0.05 sa), inverted QRS complex in leads aVR, aVL, and CV5RL, and a small Q in lead I (0.05 mV) | Left BBB | 1/6 (17%) | ||||
pBK-CMV | Reversal polarity of the T wave, R wave greater than 2.5 mV in lead II, III, aVF, and CV6LL, MEAD less than +40º | Left ventricular enlargement | 3/6 (50%) | Reversal polarity of the T wave | Most often abnormal if it is found on serial EKG | 2/6 (33%) |
+ T wave more than 25% larger than the R wave, QRS complex with S wave in leads I, II, III, aVF, CV6LL and CV6LU | Right BBB | 1/6 (17%) | ||||
MEAD to the left, R wave exceeded of 2.5 mV in lead CV6LL, R wave in lead I greater than in leads III and aVF | Left ventricle enlargement | 3/6 (50%) | ||||
SS (mock-immunized) | MEAD to the left, R wave exceeded of 2.5 mV in lead CV6LL, R wave in lead I greater than in leads III and aVF | Left ventricle enlargement | 2/6 (33%) | MEAD to the left, R wave exceeded of 2.5 mV in lead CV6LL, R wave in lead I greater than in leads III and aVF | Left ventricle enlargement | 3/6 (50%) |
+ arrhythmia | Intraventricular conduction defects | 1/6 (17%) | Rhythm irregular, QRS complex premature, bizarre, and of large amplitude, T wave directed opposite the QRS | VPC | 1/6 (17%) | |
+ prolonged Q-T interval | Intraventricular conduction defects | 1/6 (17%) | Reversal in polarity of the T wave | Most often abnormal if it is found on serial EKG | 2/6 (33%) |