Complete Spontaneous Resolution of Very Frequent Premature Ventricular Contractions

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EP LAB DIGEST. 2024;24(5):6.

Dear Readers,

A 60-year-old woman was referred in May 2023 for frequent premature ventricular contractions (PVCs). She was first diagnosed with PVCs 2 years prior, in February 2021, when she developed mild palpitations. An electrocardiogram (ECG) showed that the PVCS were unifocal, in a pattern of bigeminy and trigeminy, and had a morphology consistent with an anteroseptal right ventricular outflow tract (RVOT) origin (Figure 1A). A 7-day monitor showed a 26% PVC burden (Figure 2A), and her echocardiogram was normal. As she was minimally symptomatic with normal left ventricular (LV) function, she was treated conservatively and started on metoprolol 12.5 mg per day. 

Two years later, in March 2023, her LV function remained normal on echo and a follow-up 3-day monitor showed a 30% PVC burden (Figure 2B). When she was evaluated in May 2023, her 12-lead ECG rhythm strip showed that her PVC morphology was different and consistent with a left-sided outflow tract morphology, suggesting variable exit sites for her PVCs. Therefore, a conservative approach was used, and she continued to do well clinically. 

She was seen again in follow-up in March 2024. At that time, she had no symptoms. A 12-lead ECG with a 1-minute rhythm strip showed no PVCs (Figure 1B) and a 7-day monitor showed a <0.1% PVC burden (Figure 2C). How did her PVCs disappear, and how common is that?

A recent study was published in Europace by Przybylski and colleagues¹ that looked at the natural history of PVCs in 198 young, mostly pediatric patients without structural heart disease. There were several important findings: 

1. LV dysfunction was rare. At the time of presentation, only 4% of patients had LV dysfunction.
2. Factors associated with LV dysfunction at the time of presentation included older age, increased PVC burden, complex ventricular ectopy, and increased PVC QRS duration.
3. Risk of LV dysfunction increases with increasing PVC burden and a threshold of ≥15% best discriminated between patients with and without LV dysfunction at time of presentation.
4. The development of new LV dysfunction was rare. During follow-up of patients who had normal LV function and longitudinal echocardiograms for an average of 3.6 years, only 6% developed LV dysfunction and no patient developed an ejection fraction <40%. 
5. PVC burden frequently goes down and can disappear. In patients with serial Holter monitoring over an average of 3.2 years, the PVC burden decreased significantly over time in most patients with frequent PVCs. The PVC burden decreased to <0.5% in 44% of patients.

Based on these pediatric data, the odds that the patient presented here would experience disappearance of her PVCs is actually quite high (over 40%). Is that number lower in adults or in patients with a higher burden of PVCs at baseline? Interestingly, similar findings have been found in adults with frequent PVCs. A 2015 Canadian study of 49 adult patients with a PVC burden >5% found that spontaneous resolution of PVCs occurred in 20/49 patients (41%).² The median time to spontaneous resolution was 14.1 months (range 2.6 to 45.7).

This recent study is an important reminder that the likelihood that a patient with frequent unifocal idiopathic PVCs will develop LV dysfunction is actually quite low at about 6%, and that there is a reasonable chance that the PVCs will resolve over time on their own. Therefore, the indications for catheter ablation of idiopathic PVCs should remain limited to patients with significant symptoms or baseline LV dysfunction.

Disclosures: Dr Knight has served as a paid consultant to Medtronic and was an investigator in the PULSED AF trial. In addition, he has served as a consultant, speaker, investigator, and/or has received EP fellowship grant support from Abbott, AltaThera, AtriCure, Baylis Medical, Biosense Webster, Biotronik, Boston Scientific, CVRx, Philips, and Sanofi; he has no equity or ownership in any of these companies.

References

1. Przybylski R, Meziab O, Gauvreau K, et al. Premature ventricular contractions in children and young adults: natural history and clinical implications. Europace. 2024;26(3):euae052. doi:10.1093/europace/euae052

2. Lee AK, Andrade JG, Bennett MT. Spontaneous resolution of idiopathic frequent Premature ventricular complexes. Canadian J Card. 2015;31(10):S255-S256. doi:10.1016/j.cjca.2015.07.534