Ventricular tachycardia (VT) is a continuum, or a sequence or “a run” (or a “paroxysm”) of VPCs (by some definitions, three or more). When extremely rapid it shortens the cardiac diastolic filling phase enough to severely compromise both hemodynamics AND electrophysiological stability (especially in patients with a sick myocardium). In rare and extreme cases, this might degenerate into even more life-threatening (“malignant”) ventricular arrhythmia such as ventricular flutter (see the case below) or even ventricular fibrillation (a lethal condition resulting from chaotic ventricular electrical activity leading to complete cessation of blood pumping through the heart and, therefore, throughout the body).
HR = 364 bpm, QRS = 120 ms, R = 0.4 mV, QT = 280 ms | view the full report
However, in many veterinary patients, there is no such background and ventricular tachycardia, although potentially dictating a very rapid heart rate is not necessarily fast enough to trigger such life-threatening complications, especially if the myocardium is healthy to begin with. The following cases demonstrate VT originating at the left ventricle:
By contrast, the cases below demonstrate VTs originating from the right ventricle (see the brief discussion in this post about the morphological features of VPCs reflecting their origin at the left versus the right ventricle).
HR = 364 bpm, QRS = 120 ms, R = 0.4 mV, QT = 280 ms | view the full report
WRITTEN BY
DAN G. OHAD
DVM, Ph.D. Diplomate ACVIM (Cardiology) Diplomate ECVIM-CA (Cardiology)