Electrocardiographic changes inT. cruzi-infected rats after the ajmaline test

Bestetti, R. B.; Soares, Edson García; Sales-Neto, V. N.; Araujo, Rosaly Corrêa de; Oliveira, João Samuel Meira de

doi:10.1007/bf01852082

Cited by 2 publications

(5 citation statements)

References 21 publications

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“…However, since these methods cannot be applied to experimental animals, an experimental model for the indeterminate form of Chagas' disease that is simple enough for extensive use is still unavailable. When we used a single ECG lead [11] followed by a complete ECG study (9 leads) [12], we obtained about the same percentage in T. cruzi-infected rats. Our experiments were based on the findings by Chiale et al [13] that 30~ of patients with the indeterminate form of Chagas' disease present ECG abnormalities evoked by IV injection of ajmaline.…”

mentioning

confidence: 58%

“…We have previously conducted a study in which ajmaline provoked electrocardiographic changes (not observed in controls) thought to be representative oflatent Chagas' heart disease [12]. However, since we did not perform a simultaneous pathological study, these changes were only speculative.…”

Section: T Cruzi-infected Ratsmentioning

confidence: 96%

“…The electrocardiographic changes elicited by ajmaline in normal rats (increase in P-wave duration, PR interval, and QRS complex) have been described in detail in previous papers [11,12,[16][17][18]. All of these electrocardiographic changes are thought to be the consequence of the increased duration of both the action potential and the refractory period induced by ajmaline in all cardiac tissues.…”

Section: Control Ratsmentioning

confidence: 99%

“…After obtaining the resting ECG, each animal was submitted to the ajmaline test, as previously described [12]. A Funbec, ECG-3 model electrocardiograph was used to trace the electrocardiogram at a paper speed of 100 mm/sec and at 2N amplitude.…”

Section: Electrocardiographic Tracingsmentioning

confidence: 99%

“…The criteria for determining ECG abnormalities after the ajmaline test have been described elsewhere [12]. Briefly, the fifth and the 95th percentiles for each of the above electrocardiographic parameters were established after the ajmaline test using the normal values obtained from control rats in our laboratory.…”

Section: Electrocardiographic Tracingsmentioning

confidence: 99%

See 4 more Smart Citations

The ajmaline test as a method to disclose latent experimental Chagas' heart disease

Bestetti¹,

Soares²,

Sales-Neto³

et al. 1989

Cardiovasc Drug Ther

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Forty-one chronically T. cruzi-infected male adult albino rats with normal resting ECG were submitted to the ajmaline test (1 mg/kg body weight injected into the dorsal vein of the penis). Twenty-one similar noninfected animals served as controls. Ajmaline induced the following ECG alterations in control rats: A decrease in heart rate, an increase in heart rate, an increase in P-wave duration, an increase in PR interval, lengthening of the QRS complex, and left axis deviation in 33%, 28%, 14%, 90%, 100%, and 33% of the animals, respectively. Ajmaline evoked similar alterations in 29 of 41 (71%) T. cruzi-infected rats. However, 12 of 41 (29%) infected rats showed ECG changes of a magnitude not seen in controls: P-wave enlargement, first-degree AV block, lengthened QRS complex, and first-degree AV block plus lengthened QRS complex in 7%, 12%, 14%, and 4% of the animals, respectively. Microscopical lesions were not found in control rats. However, 22 of 41 (53%) infected rats were found to have the following pathological lesions: mononuclear cell infiltrate, necrosis, myocyte vacuolization, and interstitial fibrosis in 56%, 39%, 29%, and 7% of the animals, respectively. By comparing the ECG changes evoked by ajmaline not seen in controls with the concomitant pathological lesions, the ajmaline test was found to have 54% sensitivity, 100% specificity, and 100% positive predictive value. Thus, the ajmaline test appears to be useful for unmasking myocardial disease and therefore may be considered a potential method for the full characterization of the indeterminate form of Chagas' disease in experimental animals.

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mentioning

confidence: 58%

Section: T Cruzi-infected Ratsmentioning

confidence: 96%