P969
Improvement of left ventricular ejection fraction in the first week post rhythm restoration as a marker of long-term recovery of arrhythmia-induced cardiomyopathy in a latin american population

The incidence of Arrhythmia-Induced Cardiomyopathy (AIC) is presumed to be between 8% and 34%. Its outcome is also not well known and may be linked to multiple factors. However, it has been suggested that a 25% improvement of the Left Ventricular Ejection Fraction (LVEF), during the first week after rhythm restoration could be an indicator of long-term and complete recovery. This fact has not been studied in our country or even in Latin America.

To observe the behavior of the LVEF after restoration of sinus rhythm in patients with systolic dysfunction presumably secondary to AIC, at least in one year of follow-up.

We evaluated all patients referred for arrhythmia treatment and having any degree of systolic dysfunction (LVEF less or equal to 50%) and functional class deterioration between January 2015 and September 2018. Restoration of sinus rhythm was accomplished in either by pharmacologic or invasive methods aimed to specific arrhythmias. After the treatment, we proceed with the systolic function evaluation starting one week after rhythm control, and then at one, three, six and twelve months. This evaluation consisted in clinical examination, echocardiographic determination of LVEF, as well as NT-ProBNP and troponin measurements.

We identified twenty one cases with presumed AIC. Sixteen cases were secondary to atrial flutter, with four others being secondary to atrial fibrillation, and the last one being a consequence of frequent ventricular extrasystoles (VES). Fifteen patients (74%) were male, mean age was 51 years old (4-76 years). All cases of tachycardia had a ventricular rate over 100 beats per minute. The patient with VES, had a 58% burden of ectopic beats. Eighteen of these patients were taken to invasive electrophysiological study and radiofrequency ablation; and three patients received antiarrhythmics as rhythm control strategy. All patients had mid-range to severe systolic dysfunction prior to treatment, with a mean LVEF of 38%±7,5%; 63% of them were in NYHA class III-IV. One week after rhythm restoration, mean LVEF was 54± 6,36%. That was an improvement of 45% in LVEF. Mean LVEF at one and three months was 63± 5,43%, 61± 5,23% at six months and 63± 5,43% at one year. All patients improved their functional class, to NYHA I at the first evaluation post rhythm restoration. We found no differences between troponin and NT-ProBNP levels before and after treatment, except for one patient .

Appropriately treated AIC seems to have a good prognosis and short-term recovery of LVEF could be a useful indicator of complete normalization in the long-term. To our knowledge, here we detail the results of a relatively large time-series of AIC, and is perhaps the first study in the Latin American region that suggests that early LVEF improvement could predict AIC recovery, but controlled trials should be done in order to confirm these results.