Premature ventricular contractions: Reassure or refer?
ABSTRACTWhen patients present with palpitations, the primary care physician can perform the initial evaluation and treatment for premature ventricular contractions (PVCs). Many patients need only reassurance and do not need to see a cardiologist.
KEY POINTS
- The focus of the initial evaluation is to determine whether there is underlying structural heart disease. If there is, early referral to a specialist is probably warranted.
- Idiopathic PVCs (in which there is no structural heart disease) have a benign prognosis.
- Treatment of PVCs is indicated for relief of symptoms if reassurance is not sufficient.
- Patients who have a high PVC burden (> 10% of total heartbeats, though this is a subject of debate) should have an evaluation of their systolic function. If it is normal at baseline, periodic follow-up echocardiograms should be considered.
- Patients with a very high burden (> 20%) are at high risk of arrhythmia-induced cardiomyopathy. In these patients, referral is prudent, as some patients may opt for more aggressive treatment of their PVCs.
- In patients with severe symptoms for whom medical management has failed, referral for consideration of catheter ablation is reasonable.
Red flags for cardiomyopathy
- Multifocal PVCs, or nonsustained ventricular tachycardia of more than one morphology on monitoring
- Syncope associated with active exercise
- Abnormal imaging findings that are consistent with arrhythmogenic right ventricular cardiomyopathy, cardiac sarcoidosis, or amyloidosis.
WHEN TO TREAT IDIOPATHIC PVCs
In our practice we explain to patients that there are two primary indications for treating idiopathic PVCs: (1) to relieve symptoms or (2) in asymptomatic patients with presumed arrhythmia-induced cardiomyopathy, to try to reverse the cardiomyopathy by eliminating the PVCs.
Some patients report severe symptoms due to their PVCs. Other patients appear to have no symptoms whatsoever, while still others are not overly bothered by the PVCs but are concerned that they may indicate they are at increased risk of cardiac events. In this last group, an evaluation such as outlined above that discloses no evidence of structural heart disease and reassurance by the physician may be all the treatment needed.
Even if they have no symptoms or only minimal symptoms, patients with a high PVC burden require follow-up because of the association between frequent PVCs and arrhythmia-induced cardiomyopathy.14,15 What constitutes a “high” PVC burden remains a matter of debate. Left ventricular dysfunction has generally been reported at PVC burdens above 15% to 25% of the total cardiac beats, though this percentage can be as low as 10%.14
Eliminating the high burden of PVCs in patients with left ventricular dysfunction may significantly improve left ventricular systolic function.15 It is likely, however, that more than PVC burden alone contributes to the development of the cardiomyopathy.14
Given these complexities, it is reasonable to request an electrophysiology consultation for patients who have more than rare PVCs. What is rare? There is no defined standard, but a PVC burden less than 1% is reasonable.
Treatment of the PVCs may be indicated in patients with systolic heart failure receiving cardiac resynchronization therapy, ie, a biventricular pacemaker. For cardiac resynchronization therapy to be clinically beneficial, close to 100% of heartbeats need to be paced, and frequent PVCs, even at a burden less than 10%, may undermine its effectiveness.16
HOW TO INTERVENE?
Beta-blockers and nondihydropyridine calcium channel blockers have both been used to treat symptomatic PVCs. If the patient is found to have systolic dysfunction as part of the evaluation, a beta-blocker is indicated, irrespective of any desire to treat the PVCs. Beta-blockers and calcium channel blockers both have low adverse effect profiles. They are available in once-a-day formulations and are inexpensive. Their efficacy is variable. The use of these medications is well within the purview of the primary care physician.
Selective beta-blockers are the first choice in treatment, and metoprolol is commonly used in clinical practice. We start with a low dose and increase it based on symptom relief.
As noted, only nondihydropyridine calcium channel blockers should be used for treatment of PVCs. As with beta-blockers, we start at a low dose and increase as needed based on the response to therapy.
Antiarrhythymic drugs are classified according to the Vaughan-Williams system. The ones most frequently used for PVCs are the class Ic drugs propafenone and flecainide and the class III drugs sotalol, amiodarone, and dofetalide. However, in our experience, if first-line agents (ie, beta-blockers and nondihydropyridine calcium channel blockers) are unsuccessful in controlling the patient’s symptoms, most primary care physicians are uncomfortable prescribing class Ic and class III drugs. Failure of a beta-blocker, a calcium channel blocker, or both often results in referral to a cardiologist or electrophysiologist.
The consultation should include a careful discussion with the patient regarding the risk of treatment with a type I or a type III drug vs catheter ablation. Treatment with class I or class III antiarrhythmic drugs always entails a small risk of proarrhythmia. The choice between drug therapy or ablation therapy is highly individualized. However, if elimination of the PVCs is of paramount importance, such as in cases of arrhythmia-induced cardiomyopathy, ablation therapy is more effective at eliminating the PVCs, although at the cost of an invasive procedure. Fortunately, the risk of complications with ablation therapy is quite low.
No drugs are approved by the US Food and Drug Administration for treating PVCs or nonsustained ventricular tachycardia. The drugs that do have an indication for treatment of ventricular arrhythmias are labeled as being indicated for “sustained” or “life-threatening” ventricular arrhythmias. The use of drugs for the treatment of PVCs or nonsustained ventricular tachycardia represents off-label usage.
Referral to discuss catheter ablation of the PVCs6 should be considered for patients who:
- Have undergone unsuccessful attempts at drug therapy for either symptoms or PVC-related cardiomyopathy
- Refuse drug therapy but have severe symptoms, or
- Do not respond to cardiac resynchronization therapy due to suboptimal pacing due to PVCs.
