In patients with congenital heart disease who undergo transcatheter pulmonary valve replacement (TPVR) with either balloon-expandable or self-expanding pulmonary valve replacement (BEPVR and SEPVR), a retrospective study and a registry study show that arrhythmias are common in the early period, with differences over time and by device. Both studies were published March 23 in JACC: Clinical Electrophysiology.

In the retrospective review, Anthony C. McCanta, MD, et al., included 68 patients with a mean age of 41 years; a third were women. Most had undergone BEPVR (n=49; 72%) vs. SEPVR (n=19; 28%). The most common diagnosis was tetralogy of Fallot (46%), followed by congenital pulmonary valve stenosis (24%), bicuspid aortic valve status-post Ross procedure (15%) and acquired pulmonary valve disease (8%).

The primary composite outcome was all-cause mortality or a life-threating arrhythmia, defined as ventricular fibrillation, resuscitated sudden cardiac arrest (SCA), appropriate ICD discharge, sustained ventricular tachycardia (VT) or high-grade atrioventricular block.

Results at a median follow-up of four years showed that 35 patients (52%) experienced a total of 59 arrhythmic events; 15 patients had multiple arrhythmic events recorded. Median time to first arrythmia was 0.5 years.

A primary outcome occurred in 18 patients (26%). Looking at the components of the endpoint, eight patients died (12%) and 13 patients (19%) experienced a life-threatening arrhythmia; five had sustained VT and eight had high-grade heart block. The authors note that 12 of the 13 life-threatening arrhythmias occurred in patients who received BEPVR (p=0.09).

For the secondary endpoint of non–life-threatening arrythmia, the most common was nonsustained VT (NSVT), which occurred in 32 patients (47%). NSVT occurred more often after SEPVR vs. BEPVR (68% vs. 39%; p=0.03).

No significant association was found between SEPVR and the primary outcome (hazard ratio [HR], 0.50; p=0.28) or reduced incidence of life-threating arrhythmia (HR, 0.19; p=0.10). After adjusting for age and sex, there was no significant association between valve type and non–life-threatening arrythmia (HR, 1.97; p=0.06).

In this real-world cohort of TPVR patients with “diverse cardiac diagnoses who did not undergo pre-emptive [electrophysiology] intervention,” arrhythmias were common and were observed across the entire follow-up, write the authors. They add that longer-term surveillance is needed to understand the significance of NSVT post TPVR.

“Do the enhanced rates of NSVT augur a worse future for the SEPVR patient cohort?” asks Robert H. Pass, MD, in an accompanying editorial comment. “This is clearly a topic that calls for a longer, multicenter study, given the relatively small rates of SCA, the relative novelty of SEPVR, the variable designs of the two most commonly implanted devices, and the relatively low numbers of these patients in a single center.”

In the SERVE Registry study, Aimee K. Armstrong, MD, FACC, et al., tracked ventricular arrhythmias (VAs) post SEPVR in 513 patients at 25 centers across the U.S during the first six months post TPVR. Their median age was 28 years and 42% were women. Of the patients, 359 received the Harmony TPV and 154 the Alterra Adaptive Prestent System with the Sapien 3 Valve.

Results showed that 29% of patients had VA during the procedural admission. Patients who received the Alterra valve, compared with the Harmony valve, were more likely to have VA during the procedural admission (37% vs. 26%; p=0.014), as well as undergo treatment for VA and have delayed discharge for VA. Most VAs were NSVT (96%).

At six months, the predicted probability of VA burden fell below baseline for patients in the Harmony valve group (–6%; p<0.001) and fell to baseline in patients in the Aterra group (p=0.53). Severe VA events were rare during follow-up, and there were no known deaths due to arrythmia.

On adjusted multivariable analysis, only higher right ventricular ejection fraction and the Alterra valve were associated with a higher risk of VA during the procedure admission, while older age and baseline arrhythmic medication were potentially protective. Notably, at six months, only baseline VA burden and the Alterra valve were associated with higher VA risk, and no factors were protective.

Armstrong, et al., write that the Alterra frame may be an independent risk factor in part “because of the sharper apices of the stent frame or their outward angulation compared to the Harmony frame. These apices may cause more mechanical irritation of the myocardium.”

In an accompanying editorial comment, Victor Waldmann, MD, PhD, and colleagues write that early VAs after SETPV implantation are common “but are predominantly nonsustained, infrequently malignant, and mechanistically distinct from the scar-related re-entrant VTs that drive long-term risk in repaired [tetralogy of Fallot].” They add that future investigations with standardized rhythm surveillance, detailed assessment of device-myocardium interaction, longer term follow-up, and evaluation of proactive electrophysiological strategies “will be essential to determine whether early arrhythmic signals carry implications for later substrate evolution.”