Effects of experimental pulmonary embolism on electrocardiographic parameters, blood pressure, exercise tolerance and cardiac morphometry in the domestic dog (canis familiaris)
Abstract
Thirty 8 inch long polyvinyl chloride threads were used to
experimentally induce pulmonary embolism in mongrel dogs.
Electrocardiographic parameters in the six limb leads and blood
pressures in the pulmonary artery, right ventricle and right atrium
were measured before and also during a 35 day period following
insertion of threads in the pulmonary artery. Exercise tolerance was
assessed before and 33 days following thread insertion. At the end of
the experimental period the dogs were euthanised and morphometry
of their hearts studied. Similarly, morphometry of hearts from control
dogs was also studied.
The amplitude and frequency of Q wave in lead I, recorded
during the 35 days following thread insertion was significantly lower
than the baseline value. The amplitude of R wave in lead II on days
21-35 and of S wave in lead aVR on days 7-35 after thread insertion
was significantly lower than the baseline value. The S wave in lead I
was only present after thread insertion. The duration of the QRS
complex was significantly longer than the baseline value on the 14th
day after thread insertion. Five out of twelve (41.6%) dogs showed
right axis deviation following thread insertion. The amplitude of T
wave in leads II and III on days 2 and 3, and of aVF on days 1-3 was
significantly higher than the respective baseline values following
thread insertion. In leads aVR and aVL the values were significantly
lower than the respective baseline value on day 3 after thread
insertion. In addition in lead aVL, T wave amplitude was significantly
higher than the baseline value on day 7 after thread insertion. The
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following arrhythmias were noted during the 35 days following thread
insertion: supraventricular premature beats, first degree heart block,
ventricular premature beats, junctional tachycardia, ventricular
tachycardia, second degree heart block and sinus tachycardia.
Immediately following thread insertion the pulmonary arterial
and right ventricular blood pressures rose significantly. Thereafter the
pressures dropped, but remained at levels which were still higher
though not all were significantly different from respective baseline
values. Right atrial pressure remained unchanged throughout the
experimental period. The hearts of experimental dogs at the end of
the 35 day period did not show any significant change in weight nor in
right or left ventricular wall size when compared to the controls.
Exercise tolerance remained unchanged throughout the experimental
period. Mean rectal temperature, pulse and respiration rates during
the experimental period remained within the normal range.
It is concluded that for Kenya mongrel dogs whose baseline
electrocardiogram has been established in the present study and also
for any other dog whose baseline electrocardiogram is known, a
diagnosis of pulmonary embolism could be made and the progression
of the embolism followed by examining changes in the QRS complex
and the T wave. Also pulmonary hypertension can be achieved using
pulmonary emboli in the form of polyvinyl chloride threads.
Citation
Onyango, E.M(1992). Effects of experimental pulmonary embolism on electrocardiographic parameters, blood pressure, exercise tolerance and cardiac morphometry in the domestic dog (canis familiaris)Sponsorhip
University of NairobiPublisher
Department of Animal Physiology, University of Nairobi
Subject
Pulmonary embolismElectrocardiographic parameters
Blood pressure
Exercise tolerance
Cardiac morphometry
Domestic dog (canis familiaris)
Description
Msc Thesis