New Practice Corrects Pump Function in Heart Failure

Late-breaking results from the ElectroCRT trial presented today at EHRA 2019¹ a European Society of Cardiology (ESC) congress, pave the way for a new standard of care to improve the heart’s pump function in selected patients with heart failure.

Cardiac resynchronisation therapy (CRT), or biventricular pacing, is used to treat heart failure patients with left bundle branch block. Electrical impulses that travel from the atria to the ventricles are delayed or blocked, causing a prolonged and abnormal heartbeat. For CRT, a pacemaker is implanted below the collarbone and three leads are attached in the heart to resynchronise the contraction by stimulation with pulses of electricity.

CRT alleviates symptoms, such as breathlessness and fatigue, and reduces mortality, yet 30–40% of patients do not improve (non-responders). One of the most important modifiable causes of non-response to CRT is non-optimal positioning of the left ventricular lead.

ESC guidelines advise placing the left ventricular lead at the back of the heart where late activation occurs, as this improves response to CRT.² This is the current standard of care practice. The study focused on how to identify this site more precisely.

Previous randomised controlled trials have shown improved response to CRT, compared to standard care, when multimodality imaging is used to identify the latest mechanically activated segment for left ventricular lead placement. But multimodality imaging is time consuming and costly.

This study investigated whether lead placement at the region with the latest electrical activation would be superior to the region with the latest mechanical activation. The method uses electrical measurements obtained during the implant procedure and does not require pre-implant imaging.

The study design has been published.³ Briefly, 122 heart failure patients were randomly allocated to left ventricular lead placement at the latest electrically activated site (using electrical mapping) or the latest mechanically activated site (using imaging). Neither treatment is the current standard of care. Patients and staff responsible for follow-up care were blinded to the procedure. The primary outcome was change in left ventricular pump function (ejection fraction) at six months.

The absolute increase in left ventricular ejection fraction was significantly larger in the electrical group (11%) compared to the imaging group (7%; p=0.03). The difference was not statistically significant after adjusting for sex, baseline left ventricular ejection fraction and other factors.

Implantation took 19 minutes (22%) longer in the electrical (104 minutes) versus imaging (85 minutes) group with no increase in complications. There were no differences between groups in left ventricular reverse remodelling, New York Heart Association functional class, six minute walk test, and quality of life.

Principal investigator Dr Charlotte Stephansen, of Aarhus University Hospital, Denmark, said: “Increased left ventricular ejection fraction after CRT is associated with a better prognosis. The 4% greater increase in the electrical group is of a magnitude shown to improve functional response and cardiac event-free survival in previous studies,^4-6 indicating that the improvement is clinically important.”

The Danish-CRT trial, set to enrol 1,000 patients, is testing whether electrically guided positioning of the left ventricular lead reduces hospitalisation for heart failure or death compared to standard of care lead placement.

References and notes

¹The abstract ‘Targeting left ventricular lead implantation towards the latest electrical activation improves left ventricular ejection fraction in cardiac resynchronization therapy: a randomized controlled trial’ will be presented during the session Late-breaking trials 2 on Monday 18 March at 08:30 to 10:00 WET (GMT) in the Sokolov lecture room.

²Brignole M, Auricchio A, Baron-Esquivias G, et al. 2013 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy. Eur Heart J. 2013;34:2281–2329. doi: 10.1093/eurheartj/eht150.

³Stephansen C, Sommer A, Kronborg MB, et al. Electrically guided versus imaging-guided implant of the left ventricular lead in cardiac resynchronization therapy: a study protocol for a double-blinded randomized controlled clinical trial (ElectroCRT). Trials. 2018;19:600. doi: 10.1186/s13063-018-2930-y.

⁴Abraham WT, Fisher WG, Smith AL, et al. Cardiac resynchronization in chronic heart failure. N Engl J Med. 2002;346:1845–1853.

⁵SOLVD Investigators, Yusuf S, Pitt B, Davis CE, et al. Effect of enalapril on survival in patients with reduced left ventricular ejection fractions and congestive heart failure. N Engl J Med. 1991;325:293–302.

⁶Bristow MR, Gilbert EM, Abraham WT, et al. Carvedilol produces dose-related improvements in left ventricular function and survival in subjects with chronic heart failure. MOCHA Investigators. Circulation. 1996;94:2807–2816. https://www.ahajournals.org/doi/full/10.1161/01.CIR.94.11.2807.

About the European Heart Rhythm Association

The European Heart Rhythm Association (EHRA) is a branch of the European Society of Cardiology (ESC). Its aim is improving the quality of life and reducing sudden cardiac death by limiting the impact of heart rhythm disturbances. EHRA ensures the dissemination of knowledge and standard setting; provides continuous education, training and certification to physicians and allied professionals involved in the field of cardiac arrhythmias with a special focus on Atrial Fibrillation (AF) and Electrophysiology (EP). EHRA releases international consensus documents and position papers, it is a source of high quality, unbiased, evidence based, scientific information that promotes the quality of care for patients with AF, and for, has also dedicated a website for patients “afibmatters.org”.

About the EHRA Congress

EHRA 2019 is the annual congress of the European Heart Rhythm Association (EHRA) of the European Society of Cardiology (ESC).

About the European Society of Cardiology

The European Society of Cardiology brings together health care professionals from more than 150 countries, working to advance cardiovascular medicine and help people lead longer, healthier lives.