Predictors of myocardial recovery in pediatric tachycardia-induced cardiomyopathy.
BACKGROUND
Tachycardia-induced cardiomyopathy (TIC) carries significant risk of morbidity and mortality, although full recovery is possible. Little is known about the myocardial recovery pattern.


OBJECTIVE
The purpose of this study was to determine the time course and predictors of myocardial recovery in pediatric TIC.


METHODS
An international multicenter study of pediatric TIC was conducted. Children ≤18 years with incessant tachyarrhythmia, cardiac dysfunction (left ventricular ejection fraction [LVEF] <50%), and left ventricular (LV) dilation (left ventricular end-diastolic dimension [LVEDD] z-score ≥2) were included. Children with congenital heart disease or suspected primary cardiomyopathy were excluded. Primary end-points were time to LV systolic functional recovery (LVEF ≥55%) and normal LV size (LVEDD z-score <2).


RESULTS
Eighty-one children from 17 centers met inclusion criteria: median age 4.0 years (range 0.0-17.5 years) and baseline LVEF 28% (interquartile range 19-39). The most common arrhythmias were ectopic atrial tachycardia (59%), permanent junctional reciprocating tachycardia (23%), and ventricular tachycardia (7%). Thirteen required extracorporeal membrane oxygenation (n = 11) or ventricular assist device (n = 2) support. Median time to recovery was 51 days for LVEF and 71 days for LVEDD. Two (4%) underwent heart transplantation, and 1 died (1%). Multivariate predictors of LV systolic functional recovery were age (hazard ratio [HR] 0.61, P = .040), standardized tachycardia rate (HR 1.16, P = .015), mechanical circulatory support (HR 2.61, P = .044), and LVEF (HR 1.33 per 10% increase, p=0.005). For normalization of LV size, only baseline LVEDD (HR 0.86, P = .008) was predictive.


CONCLUSION
Pediatric TIC resolves in a predictable fashion. Factors associated with faster recovery include younger age, higher presenting heart rate, use of mechanical circulatory support, and higher LVEF, whereas only smaller baseline LV size predicts reverse remodeling. This knowledge may be useful for clinical evaluation and follow-up of affected children.
['Moore|Jeremy P|JP|', 'Patel|Payal A|PA|', 'Shannon|Kevin M|KM|', 'Albers|Erin L|EL|', 'Salerno|Jack C|JC|', 'Stein|Maya A|MA|', 'Stephenson|Elizabeth A|EA|', 'Mohan|Shaun|S|', 'Shah|Maully J|MJ|', 'Asakai|Hiroko|H|', 'Pflaumer|Andreas|A|', 'Czosek|Richard J|RJ|', 'Everitt|Melanie D|MD|', 'Garnreiter|Jason M|JM|', 'McCanta|Anthony C|AC|', 'Papez|Andrew L|AL|', 'Escudero|Carolina|C|', 'Sanatani|Shubhayan|S|', 'Cain|Nicole B|NB|', 'Kannankeril|Prince J|PJ|', 'Bratincsak|Andras|A|', 'Mandapati|Ravi|R|', 'Silva|Jennifer N A|JN|', 'Knecht|Kenneth R|KR|', 'Balaji|Seshadri|S|']
D000293:Adolescent D009202:Cardiomyopathies D002648:Child D002675:Child, Preschool D005260:Female D005500:Follow-Up Studies D006352:Heart Ventricles D006801:Humans D007223:Infant D008297:Male D009206:Myocardium D011379:Prognosis D013610:Tachycardia D016896:Treatment Outcome D016277:Ventricular Function, Left
Cardiomyopathy Antiarrhythmic drugs Catheter ablation Supraventricular tachycardia Ventricular remodeling