“Interestingly, the improvements in mortality and functional capacity with AVNA were not accompanied by a significant LVEF improvement,” comment Dr. Prashanthan Sanders, with the Royal Adelaide Hospital, and colleagues in their report in the February 21st issue of the Journal of the American College of Cardiology.
They point out that the benefit of cardiac resynchronization therapy (CRT) is well established in patients with symptomatic heart failure and sinus rhythm, but less so in patients with atrial fibrillation and heart failure.
To assess the value of AV nodal ablation in this setting, they analyzed data from six studies involving 768 CRT-AF patients, of whom 339 underwent AV ablation and 429 received medical therapy alone for rate control.
All-cause mortality was reduced significantly with AVNA compared with medical therapy (risk ratio 0.42), as was cardiovascular mortality (RR 0.44), the investigators report.
Also, the mean difference in NYHA functional class of -0.34 favored patients undergoing AVNA, Dr. Sanders and colleagues found.. However the increase in left ventricular ejection fraction with AVNA compared to medical therapy was not statistically significant.
In discussing the findings, they suggest that one reason AVNA has not been widely adopted for atrial fibrillation patients on cardiac resynchronization therapy is concern about pacemaker dependence. However, they note, complications associated with loss of pacemaker function in this setting are very rare and none were reported in the current studies.
Still, they conclude: “To confirm these data, prospective evaluation of AVNA in CRT-AF patients by randomized controlled trial is warranted.”
Nonetheless, the authors of a related editorial exclaim, “The picture is now clear!”
Dr. Maurizio Gasparini and Dr. Paola Galimberti with the IRCCS Istituto Clinico Humanitas in Milano, Italy, say the meta-analysis seems to provide definitive evidence of a survival benefit with AV junction ablation in patients with AF and heart failure on CRT. They advise, “Currently, AVJ ablation should always be considered a fundamental step of a ‘combined strategy’ to obtain the best results of CRT in this complex HF population.”