Biventricular rate (BiV) limitations have been successful as they have been improving heart function and outcomes in many patients with heart attack, leave opportunities to drive more physiological rhythm alternatives cardiac resynchronization therapy (CRT).
Both their packet rate (HBP) and their packet rate (LBP) have they emerged as candidates in recent years, not as BiV rhythm substitutions, necessarily, but as additional tools to increase the effectiveness of CRT in more patients.
Data from randomized trials on these CRT rhythm alternatives have been scarce. But that supply ended with the publication of a second such study below His-SYNC, which has compared BPH with the BiV rate in patients with heart failure.
A la His-Alternative trial, 50 patients who experienced strict clinical, echocardiographic and ECG they were randomly assigned the criteria that qualified them for the BiV CRV in the BPH or the BiV rate as a first-line corrective strategy.
BPH achieved a long-lasting and successful CRT in nearly three-quarters of the patients in whom it was attempted, including as a backup in a patient with an unsuccessful BiV-rate compromise. The remaining 28% in which BPH was unsuccessful shifted to the BiV rate.
All patients in the study achieved a successful CRT using one or other methods, with “Their CRT resulting in a significant shortening of the QRS width and significant improvements in echocardiographic parameters, as well as symptoms and physical abilities that they were comparable to the improvement seen with BiV CRT, ”said Michael Vinther, MD, PhD, when he presented the trial on April 25 during the European Heart Rhythm Association 2021 virtual congress.
“This, however, happened at the expense of higher pace thresholds,” Vinther of Rigshospitalet University Hospital in Copenhagen said, referring to a key limitation of recognized BPH.
The highest rate thresholds required for HBP to be successful, at least with currently available hardware: 1.8 V versus 1.2 V for BiV rate (Pg <.01) on implantation in the trial, the disparity is greater 6 months later - suggests pulse generators for HBP CRT may need replacement more often, Vinther said theheart.org | Cardiology Medscape. And more changes can mean more infections, among other risks.
“Its pace, as a first-line therapy, is not ready for prime time. Like now, there are some outstanding issues that we need to address first,” he said. But if a left ventricular (LV) cable for the BiV rhythm cannot be positioned enough “to obtain reasonable thresholds and avoid stimulation of the phrenic nerve, its rhythm is a good alternative.”
His group’s “impression” was that BPH was “at least as effective” as the rate of BiV for CRT in trial patients, he said, and that it would probably be enough for BPH or LBP to be successful. in selected patients with heart failure.
“I don’t think any of these rhythm modalities are for everyone. There will be patients in whom their packet rhythm will be optimal and patients where biventricular rhythm will be the solution,” said Vinther, who is also the author. main study. same day publication inside JACC: clinical electrophysiology.
“I think this will be the future. If you start with one strategy and find that it’s not feasible for one reason or another, you have options for redemption with the other strategies,” he said.
“I don’t think it’s either. I think it will be a balance between the two,” agreed Niraj Varma, MD, PhD, Cleveland Clinic, which was not part of His-Alternative. Both are likely to be more appropriate for some patients than for others, and in some individuals “it can be a mix. I can imagine scenarios where we would use a hybrid approach, a left packet cable, and an LV driver,” he said. to say. theheart.org | Cardiology Medscape.
“His-Alternative signals confirm the impressions of people doing many of these cases and of the reported cohort studies. But it’s good to have it from a randomized trial from a prestigious hospital,” Varma said. .
Much of the published observational experience His-CRT has included patients who failed to deliver LV lead or who did not respond to the BiV rhythm, he noted. Instead, His-Alternative entered a “de novo population” with conventional indications for BiV’s standard TVC. “So that’s an advantage.”
As a guest speaker after the trial by Vinther, Francisco Leyva, MD, Aston Medical School-Birmingham, UK, noted that the HBP and BiV pacing groups did not respond differently to 6-month ECG , echo and functional evaluations by intention. to be treated, but also that BPH appeared to have an advantage in the “protocol” analysis of the assay, with signs of more reverse remodeling than was achieved with the BiV rhythm.
“So I basically think the authors have the justification to say that this could represent an alternative to the biventricular rhythm,” he said. While more randomized test data would be helpful, “as it is, I think if a CRT cable isn’t implanted, it’s pretty good data to prove its pace is a useful alternative.”
The monocentric His-Alternative trial randomized 50 symptomatic patients with NYHA class 2 to 4 heart failure despite optimal medical therapy, a VS ejection fraction of 35% or less, and sinus rhythm with branch block of the NYHA. left beam defined narrowly by Strauss criteria – at the HBP or BiV pace as a first-line CRT strategy.
All patients were implanted with standard exclusive rhythm CRT (CRT-P) or CRT defibrillator (CRT-D) systems, except for the replacement of a cable in the His package by the RV cable in those assigned to HBP. . All patients and clinicians administering the different assessments were blinded to the randomization group.
Seven patients in the HBP group switched to the VS rhythm at the time of implantation and one patient switched from the VH rhythm to the BPH.
Procedure time was longer in patients assigned to BPH than at BiV rate, with a mean of 137 and 102 min (Pg <.01), respectively. But fluoroscopy times and X-ray doses did not differ significantly.
The primary endpoint, successful implantation of His-lead with left bundle capture maintained for 6 months, was achieved by 18 of the patients assigned to BPH, or 72% by ITT.
Expulsion fractions increased 16 points in the HBP group, compared with 13 points for those assigned to the BiV rate. This difference was not significant, nor were the 6-month differences in QRS duration, final VS systolic volumes, natriuretic peptide levels, 6-minute walking distance, or NYHA class, all significantly improved in both groups compared to baseline.
In the protocol analysis, the mean ejection fraction of LV was higher (48% vs. 42%; Pg <0.05) and the final systolic volume of the lower VS (65 ml vs 83 ml; Pg <.05) in the HBP group.
When only patients in whom BPH was successfully engaged were considered, Vinther said, “There are indications that they are better than with the biventricular rate. But we need more data to tell if it’s really true.”
Vinther and the other authors had no disclosures. Varma has reported consultations or interventions for Abbott, Medtronic, Biotronik, Impulse Dynamics and Boston Scientist. Leyva has revealed that he has received consulting and research sponsorship fees from Medtronic, Boston Scientific, Abbott, Biotronik and Microport.
European Heart Rhythm Association (EHRA) 2021. Innovative technology, its rhythm as an alternative to biventricular rhythm in patients with symptomatic heart failure with left bundle branch block. Filed April 25, 2021.
JACC Clin Electrophysiol. Published online April 25, 2021. Summary