A score based on four readily available clinical and imaging parameters identifies the heart failure patients who benefit most from atrial fibrillation (AF) ablation, according to late breaking science presented at the annual congress of the European Heart Rhythm Association (EHRA 2023, 16–18 April 2023, Barcelona, Spain).
AF and heart failure often coexist—with an estimated 30% of patients with heart failure going on to develop AF, patients with AF are similarly predicted to have a five-fold increased risk of developing heart disease—each condition aggravates the prognosis of the other. AF patients who develop heart failure have a three-fold increased risk of death, while in heart failure patients, the risk of death is two-fold higher when AF is also present.
Medium-sized randomised trials have produced mixed evidence on the benefit of ablation in patients with heart failure, with outcomes largely depending on the selection and characteristics of patients. Therefore, there is uncertainty about which heart failure patients should be referred for ablation. The European Society for Cardiology (ESC) Guidelines on AF recommend the procedure to reverse left ventricular dysfunction in AF patients when tachycardia-induced cardiomyopathy is highly probable. In addition, catheter ablation should be considered in selected AF patients with heart failure and reduced ejection fraction to improve survival and reduce heart failure hospitalisation.
“The tools to help clinicians determine who exactly these selected patients are and which patients have tachycardia-mediated cardiomyopathy are elusive and often subjective,” said principal investigator Marco Bergonti (Istituto Cardiocentro Ticino, Lugano, Switzerland). “Further evidence is needed to help stratify and identify those patients who will most likely benefit from AF ablation. The Antwerp score was developed to predict the response to ablation in heart failure patients with impaired (below 50%) ejection fraction.”
The score is based on four parameters: QRS width above 120 milliseconds (2 points), known aetiology (2 points), paroxysmal AF (1 point) and severe atrial dilation (1 point). Total scores range from zero to six, with zero indicating a greater likelihood of recovery. A previous single-centre study by the ANTWOORD investigators showed that the ANTWERP score estimated the probability of left ventricular ejection fraction (LVEF) recovery after ablation of AF.
The current ANTWOORD study aimed to externally validate the ANTWERP score in a large European multicentre cohort. The researchers retrospectively identified patients with heart failure, impaired Left ventricular ejection fraction (LVEF) and AF who had an ablation procedure at eight centres in Europe. Participants underwent echocardiography to assess LVEF before ablation and 12 months afterwards. The primary endpoint was sufficient improvement in ejection fraction at the 12-month echocardiography to be considered a “responder” to treatment. Responders were defined according to the 2021 universal definition of heart failure in patients with a baseline LVEF of 40–50%, an LVEF increase to 50% or more, in those with a baseline LVEF of 40% or below, an increase in LVEF of at least 10% from baseline, and a second measurement of LVEF above 40%.
The study included 605 patients. The average age was 61 years and 24% were women. Some 427 patients (70%) were classified as responders and were more likely to have positive ventricular remodelling (odds ratio [OR] 8.9, p<0.001), fewer heart failure hospitalisations (OR 0.09, p<0.001) and lower mortality (OR 0.11, p<0.001) compared to non-responders. The Antwerp score predicted LVEF improvement after ablation with an area under the curve of 0.86 (95% confidence interval [CI] 0.82–0.89; p<0.001). For total scores of zero, one, two, three, four, and five to six, the proportion of responders was 94%, 92%, 82%, 51%, 40% and 17%, respectively.
Bergonti said: “Based on our findings, patients with a low score (two or less) may benefit from early referral for catheter ablation, with a more than 90% chance of recovery. Patients with a high score (five or higher) have a very low expected recovery rate (below 20%) and hence may benefit more from alternative strategies such as aggressive rate control. Those in the intermediate zone (score three to four, expected recovery rate 47%) may benefit from further diagnostic tests such as cardiac magnetic resonance to improve their diagnostic assessment, as the presence of late gadolinium enhancement has been associated with less LVEF improvement.”