Page 71 - Rapid Review of ECG Interpretation in Small Animal Practice, 2nd Edition

Answer 11 ECG Cases

Answer 11
VetBooks.ir 1 ECG 11 shows atrial premature complexes.

2 • The average heart rate is 135 bpm. The rhythm is regularly irregular with beats occurring in pairs.
The first beat is a sinus beat and the second beat is an atrial premature beat. There is a normal
P wave in front of the sinus QRS complex of each pair. The atrial premature beat has a normal QRS
configuration and a small negative P wave (arrows).
• The interval between the first and second beat of each pair equates to an atrial premature beat rate
of 190 bpm. The term atrial bigeminy is often used in instances when the sinus and atrial premature
beats alternate in a regular 1:1 fashion.
• Atrial premature beats often occur in cases with underlying heart diseases, especially in those that
produce atrial enlargement (i.e., mitral valve disease, cardiomyopathy), but can also be secondary to a
wide variety of extracardiac conditions.

11 I

II

III

aVR

aVL

aVF

58