# Successful Functional Outcome in a Dog With Ventricular Tachycardia Treated With Antiarrhythmics, Cardioversion, Cardiopulmonary Resuscitation, and Intra‐Arrest Lipid Emulsion

## TL;DR

A dog with severe heart rhythm issues was successfully revived after a long cardiac arrest using a combination of treatments, including a special lipid emulsion to counteract medication effects.

## Contribution

Demonstrates successful use of intra-arrest lipid emulsion to counteract antiarrhythmic drug effects during resuscitation in a dog.

## Key findings

- Return of spontaneous circulation was achieved after 16 minutes of CPR with adjusted protocols.
- Lipid emulsion was used to bind lipophilic antiarrhythmic drugs, potentially lowering the defibrillation threshold.
- The dog remained stable for 12 months post-discharge despite ongoing ventricular tachycardia.

## Abstract

To describe a case of successful CPR after prolonged cardiopulmonary arrest in a dog treated for refractory ventricular tachycardia (VT) with multiple antiarrhythmic medications and attempted electrical cardioversion, resulting in suspected lidocaine toxicosis necessitating intra‐arrest IV lipid emulsion (ILE) administration.

A 6‐month‐old male intact American Cocker Spaniel was presented for evaluation of VT found on routine physical examination. A dilated cardiomyopathy phenotype was identified on echocardiography. The arrhythmia was refractory to therapy with lidocaine, magnesium sulfate, procainamide, and amiodarone. Subsequently, the dog was anesthetized for electrical cardioversion. The dog then developed ventricular fibrillation (VF), and CPR was performed per the contemporaneous Reassessment Campaign on Veterinary Resuscitation guidelines. Once the duration of VF exceeded 10 min, CPR was adjusted with a longer period of chest compressions before defibrillation. ILE was administered due to a concern for concurrent lidocaine toxicosis and to bind some of the previously administered antiarrhythmic medications, which may have increased the defibrillation threshold (DFT). Return of spontaneous circulation was achieved after 16 min of CPR. After being discharged, the dog was treated with mexiletine and sotalol long term and continued to do well 12 months later despite persistent VT.

This report describes a case of CPA secondary to intractable VT refractory to both injectable antiarrhythmic medication and attempted electrical cardioversion. Evidence suggests that antiarrhythmic medications can have positive or negative effects on the DFT, which may affect the success of electrical cardioversion or defibrillation. ILE was administered to bind the lipophilic antiarrhythmic medications due to concern that they were increasing the DFT. In patients with malignant arrhythmias, use of antiarrhythmic medication is often essential; however, clinicians should consider its potential impact on the DFT during subsequent cardioversion or defibrillation.