From the Guidelines
Premature ventricular contractions (PVCs) are typically characterized by a wide QRS complex and often display T wave inversion in their morphology, which is a key feature that helps clinicians distinguish PVCs from normal beats or other arrhythmias. When a PVC occurs, the electrical impulse originates from the ventricles rather than the normal conduction pathway, causing an abnormal ventricular depolarization. This abnormal depolarization is followed by an abnormal repolarization, which manifests as T wave inversion on an electrocardiogram (ECG) 1. The T wave inversion occurs because the direction of repolarization is opposite to the direction of depolarization in PVCs. Additionally, PVCs are characterized by absence of a preceding P wave, and often a compensatory pause following the PVC.
Some key points to consider when evaluating PVCs include:
- The presence of PVCs on 2 minutes of monitoring of middle-aged patients is associated with increased risk of both ischemic heart disease events and mortality, with or without prevalent ischemic heart disease 1
- Frequent PVCs (usually >15% of the total number of beats) may produce a reversible form of LV dysfunction, which can be effectively treated with catheter ablation 2
- PVCs are common and increase in frequency with age, and their presence is generally considered a risk factor for adverse cardiovascular outcomes 1
In terms of management, catheter ablation of the triggering focus has proved to be highly effective in eliminating the repetitive PVCs which induce ventricular fibrillation (VF) in patients with idiopathic VF 3. Additionally, beta blockers may be used to reduce the frequency of PVCs and prevent adverse outcomes. However, treatment of PVCs with antiarrhythmic medications has not been shown to reduce mortality and may even increase the risk of death in certain populations 1.
Overall, understanding the ECG characteristics of PVCs, including T wave inversion, is important for accurate diagnosis and appropriate management of patients with PVCs.
From the Research
PVCs and T-Wave Inversion
- PVCs (Premature Ventricular Contractions) are common and can be found in 3%-20% of the general population 4
- T-wave inversion in the electrocardiogram (ECG) has been associated with coronary heart disease (CHD) and mortality 5
- The pathophysiology and prognostic significance of T-wave inversion may differ between different anatomical lead groups 5
Relationship between PVCs and T-Wave Inversion
- There is no direct evidence in the provided studies that links PVCs with a T-wave inversion shape
- However, PVCs can be associated with underlying cardiac disease, which may also be related to T-wave inversion 4, 6
- Frequent PVCs can lead to cardiomyopathy, which may also affect the T-wave shape in the ECG 7, 8
Clinical Significance
- Anterior and lateral T-wave inversions are associated with an increased risk of CHD, while lateral T-wave inversion is also associated with increased risk of mortality 5
- PVCs can be asymptomatic or symptomatic, and their prognosis varies depending on the frequency and underlying heart disease 4, 8
- The evaluation and management of PVCs depend on the presence of symptoms, PVC frequency, and underlying heart disease 8