EKG Flashcards
The correct answer is atrial fibrillation. Although the rate is not fast, there are no discernible P waves and the R-R interval varies with each beat. This irregularly irregular rhythm is a hallmark of atrial fibrillation. Normal sinus rhythm and sinus arrhythmia are incorrect as there are no P waves apparent. Atrial premature complexes is wrong because the irregularity is from the fibrillation waves in the atria, not a discrete premature focus. Second degree heart block is not correct because no P waves are seen, as would be expected with intermittent block.
What is the treatment for this?
The correct answer is mexiletine. The Holter ECG shows a couplet of ventricular premature complexes. If frequent ventricular ectopy is seen, particularly with runs or R-on-T episodes, treatment is advised with oral ventricular antiarrhythmics. Mexiletine is an oral class I antiarrhythmic that is well-tolerated in dogs. Pimobendan improves systolic function, but does not treat arrhythmias. Amlodipine is a calcium channel blocker used for patients with systemic hypertension. Diltiazem is used for supraventricular tachycardias to slow conduction down the AV node. Furosemide is a diuretic used in the treatment of heart failure, it does not have antiarrhythmic properties.
