From the Guidelines
Premature ventricular contractions (PVCs) are caused by a variety of factors, including underlying heart disease, electrolyte imbalances, and certain medications, as well as lifestyle factors such as caffeine, alcohol, and tobacco use, and can also occur without any identifiable cause in people with structurally normal hearts. The causes of PVCs can be multifactorial, involving both cardiac and non-cardiac factors. Common causes include:
- Caffeine, alcohol, tobacco, stress, anxiety, fatigue, and electrolyte imbalances (particularly low potassium or magnesium) 1
- Certain medications, such as decongestants, antihistamines, and stimulants 1
- Medical conditions, including coronary artery disease, heart failure, cardiomyopathy, heart valve problems, and previous heart attacks that leave scar tissue 1
- High blood pressure and hyperthyroidism can also contribute to PVCs 1 The mechanism of PVCs involves abnormal electrical impulses originating from the ventricles, disrupting the heart's normal rhythm and causing an early beat followed by a compensatory pause. Frequent PVCs, defined as more than 30 PVCs per hour, are associated with increased cardiovascular risk and mortality, and may be a reversible cause of left ventricular dysfunction 1. If you experience frequent PVCs, especially with symptoms like dizziness or shortness of breath, medical evaluation is recommended to rule out underlying heart disease.
From the Research
Causes of Premature Ventricular Contractions (PVCs)
The causes of PVCs can be attributed to various factors, including:
- Underlying cardiac disease, such as structural heart disease (SHD) 2, 3
- Ischemic heart disease, where the frequency and complexity of PVCs are associated with mortality 4
- Myocarditis, where PVCs may be a marker of the underlying pathophysiologic process 3
- High PVC burden, which may induce cardiomyopathy and left ventricular (LV) dysfunction or worsen underlying cardiomyopathy 5, 3
- Other factors, such as electrolyte imbalance and lifestyle factors, which may contribute to the development of PVCs 3
Risk Factors for PVC-induced Cardiomyopathy
Risk factors for PVC-induced cardiomyopathy include:
- Frequent PVCs, which can lead to left ventricular systolic dysfunction (LVSD) 6, 5
- Underlying structural heart disease, which can increase the risk of PVC-induced cardiomyopathy 2, 3
- Presence of other cardiac conditions, such as congestive heart failure, which can affect the prognosis of PVCs 4
Clinical Implications
Understanding the causes and risk factors of PVCs is crucial for proper diagnosis and treatment. PVCs can be benign in the absence of structural heart disease, but they can also indicate increased risk of sudden death in certain cases 2, 4, 3. Accurate diagnosis and treatment, including catheter ablation or pharmacological suppression, can help improve left ventricular systolic dysfunction and reverse cardiomyopathy 6, 5, 3.