P5557Cardiac autoantibodies and ventricular arrhythmias in patients with biopsy-proved myocarditis

Abstract

Abstract Background Cardiac autoandibodies have been associated with dilatative cardiomyopathy in subjects with inflammatory heart disease. However, their association with ventricular arrhythmias (VA) in patients with autoimmune myocardits has never been investigated so far. Purpose To evaluate the association between cardiac autoantibodies and both baseline and FU VA in patients with a de novo diagnosis of biopsy-proved autoimmune myocarditis. Methods We enrolled 44 consecutive patients (59% males, mean age 44±13y, mean LVEF 50±10%) presenting with symptomatic VA (VF, VT, NSVT, >1ehz746.0501 PVC/24h) and a de novo diagnosis of biopsy-proved autoimmune myocarditis according to the ESC criteria. Serum anti-heart (AHA) and anti-intercalated disk (AIDA) autoantibodies were assessed at a referral center at the time of the index hospitalization. Complete baseline data, including ECG, arrhythmia telemonitoring, echocardiogram, cardiac magnetic resonance (CMR) and blood biomarkers (T-troponin, NT-proBNP) were collected. The endpoint of the study was the occurrence of major VA (VT, VF, appropriate ICD shocks) at 5y FU, as assessed by 2/y Holter ECG monitoring and (when applicable) ICD interrogation. Results At baseline evaluation, 24 (55%) and 23 patients (52%) were AHA+ and AIDA+, respectively. Clinical onset with major VA was documented in 24 patients (55%): 9 AHA+ vs. 15 AHA- (p=0.017) and 13 AIDA+ vs. 11 AIDA- (p=0.547). At presentation, no significant differences were found between AHA+ vs. AHA- and AIDA+ vs. AIDA- patients in LVEDV, LVEF, T-troponin and NT-proBNP values (all p=n.s.). Positive (2/3) Lake Louise criteria at CMR were found in 33 patients (75%; p=n.s. among different subgroups). Before discharge, 27 subjects (61%) underwent ICD implant. Optimal medical treatment was started in all of the cases, with no significant differences in betablockers, antiarrhythmic drugs and immunsuppressive therapy, among different subgroups (all p=n.s.). Overall, 10 patients (23%) experienced major VA by 5y FU: 3 AHA+ vs. 7 AHA- (p=0.147) and 9 AIDA+ vs. 1 AIDA- (p=0.013). In particular, 18 events were documented (range 1–3 episodes per patient at 2.2±1.7 y mean FU), including 3 VT episodes and 15 appropriate ICD shocks. Taking together baseline and FU data, multiple (>1) major VA episodes occurred in 8 patients: 3 AHA+ vs. 5 AHA- (p=0.436) and 8 AIDA+ vs. 0 AIDA- (p=0.005). Of note, 3/3 AHA+ patients with multiple major VA espisodes were also AIDA+ (double positivity). Conclusion In biopsy-proved autoimmune myocarditis presenting with VA, major VA occurrence by 5y FU, as well as arrhythmias recurrences, are more common among AIDA+ patients. By converse, none of the isolated AHA+ cases experienced multiple episodes of major VA. These findings may suggest distinct pathophysiological mechanisms involving the different molecular targets of cardiac autoimmunity. Acknowledgement/Funding None