Patients who feel entirely well tend to think their doctors are a little nuts when they recommend aggressive measures in response to finding PVCs on a routine ECG. Patients who are plagued by PVC-induced palpitations regard their doctors as being cruel and heartless when they refuse to entertain therapy for such a benign condition. Which patients are right? Which doctors?
In this article we will review PVCs -- what they are, what causes them, what they imply in terms of medical prognosis, how they ought to be evaluated, and how they ought to be treated.
What are PVCs?
PVCs are extra electrical impulses arising from one of the cardiac ventricles, usually the left ventricle. (Note: Click here for a review of the normal heart rhythm.) They are easily detected on an ECG. Sometimes the presence of PVCs indicates an inherent electrical instability in the heart, and therefore indicates an increased risk of sudden death. These “dangerous” PVCs are generally limited to patients with significant underlying heart disease.More often, PVCs do not indicate any inherent problem with electrical stability, and are completely benign.
Symptoms of PVCs
Most people with PVCs have no symptoms at all. They simply don’t feel them. However, a substantial minority of patients with PVCs will perceive palpitations – an unusual awareness of the heart beat. These palpitations are often described as “skipped beats.”Whether patients perceive palpitations or not is due to many factors. Some individuals are just naturally more attuned to any unusual sensations that occur in their internal organs – including PVCs. Others are blissfully unaware of their PVCs during the day, when they are active and distracted, but suddenly begin to feel them when they retire for the night and external stimuli are removed. But most do not feel them at all.
Background Info on PVCs
Our understanding of PVCs have changed dramatically over the past 30 years. At one time, they were assumed to be dangerous, and doctors were inclined to try to suppress PVCs with drugs whenever they saw them. During the last 15 to 20 years, however, careful studies have demonstrated three things: 1) In people with no significant underlying heart disease, PVCs do not indicate an increased risk. 2) In patients with significant heart disease, the presence of PVCs suggests that an already increased risk may be even higher. 3) Suppressing the PVCs with antiarrhythmic drugs does not reduce risk, and actually tends to increase the risk.How Should a Person with PVCs Be Evaluated?
Since the appearance of PVCs may indicate the presence of unsuspected underlying heart disease, when PVCs are identified on a routine screening examination, reasonable steps ought to be considered to rule out underlying disease. Such “reasonable steps” might include an echocardiogram and/or a stress test. While the appropriate evaluation needs to be individualized, in most cases at least some noninvasive testing is indicated.If underlying coronary artery disease or cardiomyopathy is found, then optimizing therapy for these conditions (often including the use of beta blockers, ACE inhibitors, and statins) will significantly reduce the risk of sudden death.
In certain subsets of patients with underlying heart disease, more aggressive steps are indicated to reduce the risk of sudden death. In some instances, an implantable defibrillator should be inserted.
Thus, the chief task of the doctor evaluating a person with PVCs is to know that PVCs are potential markers of increased risk – and then launch into a search for possible underlying heart disease.
