[Changes in the contractile myocardium in acute rhythm disorders]

Area of Science:

• Cardiovascular Pathology
• Experimental Toxicology
• Histopathology

Background:

• Arrhythmias can lead to significant myocardial damage.
• Understanding the morphological basis of non-coronary myocardiopathies is crucial for diagnosis and treatment.
• Investigating the effects of specific toxins and electrical stimuli on cardiac tissue provides insights into disease mechanisms.

Purpose of the Study:

• To investigate the morphological changes in contractile myocardium under different arrhythmia-inducing conditions.
• To compare the severity and type of myocardial lesions caused by electrical stimulation versus ammonia/barium chloride exposure.
• To examine the vascular changes in the microcirculation bed associated with these induced arrhythmias.

Main Methods:

• Induction of arrhythmias in rabbits via electrical stimulation (Group 1) or ammonia steam inhalation with barium chloride poisoning (Group 2).
• Histopathological examination of contractile myocardium at 1-3 days and 7 days post-induction.
• Analysis of microcirculation bed vascular changes, including spasm, paresis, plethora, hemorrhage, and thrombus formation.

Main Results:

• Granular and vacuolar dystrophy observed at 1-3 days, progressing to focal myocytolysis by 7 days in both groups.
• Group 2 exhibited more severe myocardial lesions, including contracture alterations, by day 7.
• Similar vascular changes (spasm, paresis, plethora, hemorrhage, thrombus formation) occurred in both groups, with earlier thrombus formation in Group 2.

Conclusions:

• Both experimental models induce distinct morphological lesions in the contractile myocardium.
• The ammonia/barium chloride model results in more severe myocardial damage and earlier vascular complications.
• The observed morphological changes are consistent with non-coronary myocardiopathies.