From the Guidelines
PVCs are considered a concern when they exceed 30 per hour, as defined by the presence of at least 1 PVC on a 12-lead ECG or >30 PVCs per hour, which is associated with increased cardiovascular risk and mortality. This definition is based on the 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death 1. The clinical significance of PVCs depends on several factors beyond just frequency, including the presence of symptoms like palpitations, dizziness, or shortness of breath, and underlying heart disease.
Key Considerations
- PVCs are common and increase in frequency with age, found in about 50% of all people with or without heart disease on longer term monitoring 1.
- The presence of PVCs on 2 minutes of monitoring is associated with increased risk of both ischemic heart disease events and mortality, with or without prevalent ischemic heart disease 1.
- Frequent PVCs are associated with increased cardiovascular risk and increased mortality, and the detection of PVCs, particularly if multifocal and frequent, is generally considered a risk factor for adverse cardiovascular outcomes 1.
Evaluation and Treatment
- Medical evaluation is recommended for individuals experiencing numerous PVCs, typically including an ECG, Holter monitor, and possibly an echocardiogram to assess heart structure and function.
- Treatment options range from simple reassurance for benign PVCs to medications like beta-blockers or calcium channel blockers, and in some cases, catheter ablation for very symptomatic or frequent PVCs. However, treatment of PVCs with antiarrhythmic medications has not been shown to reduce mortality and may increase the risk of death in certain populations 1.
From the Research
PVC Burden and Concern
The number of Premature Ventricular Complexes (PVCs) per hour that are considered a concern can vary depending on several factors, including the presence of structural heart disease and symptoms.
- Studies have shown that frequent PVCs, defined as greater than 20% of all QRS complexes on standard 24-hour Holter monitoring, are associated with the presence or subsequent development of left ventricular dilatation and dysfunction 2.
- A study found that patients with frequent RVOT PVCs (> or =10 per hour) had a significant association with left ventricular dysfunction, with a prevalence of 4%, 12%, and 34% in patients with <1000PVCs/24 hour, 1000-10,000PVCs/24 hour, and > or =10,000PVCs/24 hour, respectively 3.
- Another study suggested that an increased PVC frequency may be a risk factor for heart failure and death, and that the resolution of systolic dysfunction after successful catheter ablation of PVCs demonstrates that a causal relationship can be present 4.
Diagnostic Considerations
The evaluation of PVCs typically involves a combination of physical examination, electrocardiogram, ambulatory monitoring, and echocardiography.
- The history, physical examination, and 12-lead ECG are each critical to the diagnosis and evaluation of a PVC 4.
- An echocardiogram is indicated in the presence of symptoms or particularly frequent PVCs, and cardiac magnetic resonance imaging is helpful when the evaluation suggests the presence of associated structural heart disease 4.
- Ambulatory monitoring is required to assess PVC frequency, and a PVC burden of >20% is considered high and may be associated with cardiomyopathy and left ventricular dysfunction 2, 4.
Treatment Options
Treatment options for PVCs depend on the presence of symptoms, PVC burden, and underlying heart disease.
- Patients with no or mild symptoms, a low PVC burden, and normal ventricular function may be best served with simple reassurance 4.
- Either medical treatment or catheter ablation are considered first-line therapies in most patients with PVCs associated with symptoms or a reduced left ventricular ejection fraction, and patient preference plays a role in determining which to try first 4.