Should you worry about that ‘extra’ heartbeat?
If you sometimes sense what feels like an extra heartbeat, you’re not alone. Over the course of a normal day, it happens to about half of people, according to Adam Mohmand-Borkowski, MD, a cardiologist and cardiac electrophysiologist based at the Cape Cod Healthcare Cardiovascular Center in Hyannis.
Usually it’s nothing to worry about, but there are times when it’s a cause for concern, he said.
“This feeling of extra beats is caused by a premature ventricular contraction, or PVC,” he said. “It's triggered by electrically abnormal tissue in the lower chamber of the heart that causes a distortion in the normal electrical system of the heart.”
“This extra beat is interesting because it's not the extra beats that most people are feeling; it's the beat following the extra beat. That extra beat causes the electrical system to take a short break to reset and there's more time for the blood to come to the lower chamber of the heart. It's like a powerful beat that we feel after the extra beat.”
Some people can have frequent PVCs and be asymptomatic, while others can have disabling symptoms, he said. They can feel chronically fatigued or be unable to tolerate exercise because the extra beats interfere with normal function of the heart.
“If you have a not fully mechanically effective beat, there’s not enough blood going to the brain, so some patients feel not only palpitations or fatigue, but also lightheadedness,” he said.
For most people, it’s a benign phenomenon that may go away with time. If more than about 15-20 percent of a person’s heartbeats are PVCs, that’s a matter of concern, he said, because frequent PVCs could cause a condition called cardiomyopathy (a weakened heart muscle).
Diagnosing PVCs begins with an electrocardiogram (EKG) to reveal their frequency. “If the EKG doesn’t show any PVCs, but patients complain of palpitations, we use a Holter monitor, which you wear for 24 or 48 hours so we see how many PVCs you have,” he said.
The diagnostic process may include a stress test, since exercise can induce or suppress PVCs in some people, and echocardiogram (ECG) to see if any structural problems have been caused by PVCs.
“Some PVCs are triggered by stress, caffeine, stimulants or alcohol,” he said. “Some are caused by reversible medical causes, but it could appear in completely otherwise healthy people, and that's the majority of patients.
“If you do 24-hour monitoring, 75 percent of patients may have some very rarely occurring PVCs. But frequent PVCs, only appear in 1 to 4 percent of the population.”
People at that higher end of the spectrum are tested for other cardiac conditions. If they are otherwise healthy, it’s not unusual for the PVCs to go away without treatment, he said.
For patients at higher risk or symptomatic, treatments include beta blockers to slow the heart rate or calcium channel blockers to relax the heart. If medication doesn’t help, another option is a cardiac ablation, which cauterizes the spot in the bottom chamber of the heart causing the PVCs.
“Overall it’s a very common condition, and for the vast majority of patients it’s a benign condition,” said Dr. Mohmand-Borkowski. “But if you have frequent or symptomatic PVCs, it is reasonable to see your physician for an evaluation.”
