From the Guidelines
A run of PVCs is known as ventricular tachycardia (VTach) when it consists of three or more consecutive PVCs at a rate greater than 100 beats per minute. VTach is a distinct entity from isolated PVCs, with different implications for patient management and outcomes 1. Repolarization plays a crucial role in the development and maintenance of VTach, as abnormalities in this phase of the cardiac action potential can create a substrate for arrhythmias. According to the 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias, patients with early repolarization patterns on ECG are at increased risk for subsequent recurrent episodes of ventricular fibrillation (VF) 1.
Key points to consider in the context of VTach and repolarization include:
- The definition of VTach as three or more consecutive PVCs at a rate greater than 100 beats per minute
- The importance of repolarization in creating an environment conducive to arrhythmias like PVCs and VTach
- The potential for medications that affect cardiac repolarization to be effective in treating these arrhythmias, but also to sometimes cause them as a side effect
- The increased risk of recurrent VF in patients with early repolarization patterns on ECG, as noted in the 2017 AHA/ACC/HRS guideline 1
In terms of management, it is essential to rule out reversible causes of VTach, such as ischemia, and to consider the use of antiarrhythmic medications, although their efficacy may be limited in certain cases 1. Overall, the relationship between PVCs, VTach, and repolarization is complex, and a thorough understanding of these concepts is necessary for optimal patient care.
From the Research
Definition of VTach
- A run of PVCs is known as ventricular tachycardia (VTach) or non-sustained ventricular tachycardia (NSVT) if it is three or more consecutive PVCs 2, 3.
Repolarization and VTach
- Repolarization abnormalities can contribute to the development of VTach, as they can create a substrate for re-entrant arrhythmias 3.
- However, the relationship between repolarization and VTach is complex, and other factors such as the presence of structural heart disease and the frequency and complexity of PVCs also play a role 2, 3.
Management of VTach
- The management of VTach depends on the underlying cause and the presence of symptoms or structural heart disease 4, 2, 3.
- Treatment options include antiarrhythmic medications such as beta-blockers and class III anti-arrhythmic agents, as well as implantable cardiac defibrillators (ICDs) and radiofrequency ablation (RFA) 4, 2, 3, 5.