Abstract
Background:
Inhalation anesthesia plays a critical role in veterinary cardiology by providing stable conditions for accurate electrocardiographic (ECG) recordings in dogs. Volatile anesthetics such as sevoflurane and isoflurane are widely used due to their controllability and cardiovascular effects.

Aim:
This study aimed to evaluate the impact of these agents on ECG parameters and cardiac rhythm stability in dogs.

Methods:
Twenty healthy adult dogs were anesthetized using either isoflurane or sevoflurane under controlled conditions. Electrocardiogram parameters including heart rate, PR interval, QRS duration, and QT interval were continuously monitored. Data were statistically analyzed to assess differences between the two anesthetic protocols.

Results:
Sevoflurane demonstrated significantly improved ECG stability, reduced waveform variability, and fewer arrhythmogenic changes compared to isoflurane (p < 0.05). Heart rate was higher and PR intervals were shorter under sevoflurane, while QRS duration showed no significant difference between groups. ECG clarity was also superior with sevoflurane.

Conclusion:
Sevoflurane provides more stable and reliable conditions for ECG recording in dogs compared to isoflurane. Its rapid induction and recovery, along with minimal cardiovascular disturbance, make it the preferred anesthetic agent for clinical and research applications.

Key words: Cardiac function; Canine anesthesia; Electrocardiogram; Isoflurane; Sevoflurane.