August 30, 2016 — Medtronic plc announced results from the Cardiac Resynchronization Therapy Efficacy Enhancement (CRTee) study at the 2016 European Society of Cardiology (ESC) Congress in Rome. The study showed that the Medtronic-exclusive device-based EffectivCRT during AF algorithm improves therapy delivery in heart failure patients with atrial fibrillation (AF).
Current CRT devices report "percent pacing" — a measure of whether the device sends a pacing pulse to stimulate the heart. However, current devices do not report the effectiveness of each pacing stimulus — that is, whether the pacing pulse "captures" the heart muscle and improves its pumping ability.
The new EffectivCRT during AF feature automatically determines the effectiveness of each left ventricular pace and adjusts pacing rates during AF. This is important for heart failure patients suffering from AF, because the pacing pulse from the device is more likely to be ineffective or interrupted because of this irregular heart rhythm.
"This technology brings us one step closer to understanding effective left ventricular pacing for AF patients receiving CRT, which has been difficult to manage in the past" said Suneet Mittal, M.D., director, electrophysiology laboratory, Arrhythmia Institute of the Valley Health System, Ridgewood, N.J. "We can now optimize treatment to a larger patient base, including difficult-to-treat non-responders, to hopefully prevent patients from undergoing additional treatments and often invasive follow-on procedures."
The EffectivCRT Diagnostic and EffectivCRT during AF algorithm are available on the Claria MRI Quad CRT-D SureScan in Europe.
The EffectivCRT features are investigational only in the United States; the Claria CRT-D is not approved for sale in the U.S.
The Claria device, which is approved for full-body magnetic resonance imaging (MRI) scans in 1.5 and 3T machines, can be paired with Attain Performa quadripolar lead technology. In addition to the new EffectivCRT features, the Claria device includes the Medtronic-exclusive AdaptivCRT algorithm, which has been shown to provide a 46 percent reduction in AF risk1 and reduce a patient's odds of a 30-day heart failure readmission by 59 percent2.
CRTee was a prospective, randomized, crossover study of 71 patients with paroxysmal, persistent or permanent AF. Sixty-six patients were randomized first to either an existing algorithm or the new EffectivCRT algorithm, with the desired outcome of a higher percent of effective CRT being delivered during AF. Fifty-four patients completed both arms. The EffectivCRT group increased effective pacing during AF by 7 percent, from 81 percent to 88 percent, p<0.001. Heart rate increased by only three beats-per-minute, from 77 to 80 BPM, p<0.001. Patients with a low percent of pacing at baseline (less than or equal to 80 percent) received the greatest benefit (average absolute increase of 15 percent effective pacing).
For more information: www.medtronic.com
1 Martin DO, et al. Clinical Outcomes with Adaptive Cardiac Resynchronization Therapy: Long-Term Outcomes of the Adaptive CRT Trial. HFSA Late Breakers. September 23, 2013.
2 Starling RC, Krum H, Bril S, et al. Impact of a Novel Adaptive Optimization Algorithm on 30-Day Readmissions: Evidence From the Adaptive CRT Trial. JACC Heart Fail. July 2015;3(7):565-572.
July 21, 2025 
