A recent study published in The American Journal of Cardiology indicates that cardiac resynchronization therapy (CRT) is associated with improved survival in patients with transthyretin amyloid cardiomyopathy (ATTR-CM) who have significant heartbeat pacing problems.
In ATTR-CM, misfolded TTR proteins in the heart muscle often disrupt its natural electrical signaling, which can cause heart rate problems. Some patients need a pacemaker or defibrillator to help maintain a steady rhythm, but these standard devices can sometimes cause the heart’s chambers to beat out of sync if they are relied upon too heavily. The study’s authors found that when the device takes over the heart’s pacing 40% of the time or more, this lack of coordination can lead to poorer clinical outcomes.
A CRT device is a special type of pacemaker that synchronizes contractions of the heart’s ventricles. While patients with ATTR-CM who receive CRT often present with more advanced disease, the study found that these patients appear to have better survival than those who receive high levels of standard right ventricular pacing (RVP) via permanent pacemakers or implantable cardioverter-defibrillators. (The authors defined high levels of RVP as greater than the 40% threshold.)
Read more about ATTR-CM signs and symptoms
In this retrospective study, 105 patients with ATTR-CM were categorized into three groups based on device type and pacing needs: One group had pacemakers and defibrillators and low RVP, the second group had pacemakers and defibrillators and high RVP and the third group had received CRT.
While hospitalization rates were higher in both the CRT and high RVP groups compared to those with minimal RVP needs, this trend likely reflects greater baseline disease severity in these patients. Advanced stages of ATTR-CM were significantly more common in both the high RVP group and the CRT group.
A critical observation during the median 3.1-year follow-up period was the dynamic nature of pacing requirements in ATTR-CM patients. In the group initially identified with a low RVP burden, the need for pacing increased substantially over time, rising from an average of 3.9% at implantation to over 26% at the final measurement. This trend contrasts with the high RVP and CRT groups, where pacing needs remained consistently high and stable throughout the study.
The authors suggested that CRT may be a better option than pacemakers or defibrillators for patients with high RVP or advanced disease. “These results advocate for careful consideration of device selection in ATTR-CM patients, with a potential preference for CRT upfront in those with high pacing needs and advanced NAC stages,” the researchers noted. However, they emphasize that further large-scale clinical trials are necessary to confirm these benefits and establish definitive guidelines for clinical practice.
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