Tachycardia-Induced Cardiomyopathy: A Case Series and a Literature Review.

Tachycardia-induced cardiomyopathy (TIC), also known as arrhythmia-induced cardiomyopathy or tachycardiomyopathy, is a reversible form of heart failure characterized by persistent tachyarrhythmias and associated ventricular dysfunction. TIC is characterized by the reversal of myocardial damage with resolution of the arrhythmia. Early diagnosis of TIC is imperative, as the treatment course is distinct from cardiomyopathy of other or unknown causes. However, distinguishing TIC from tachycardia secondary to increased catecholamines due to congestive heart failure can be very challenging. There are relatively few paediatric reports, and herein we present a case series of 48 paediatric patients with TIC from literature (2014-2024). We also present 4 illustrative cases with TIC seen at our site (BC Children's Hospital, Vancouver, Canada). The mean age in this case series was 6.98 ± 4.9 years. The majority of patients had ectopic atrial tachycardia (41.7%), followed by permanent junctional reciprocating tachycardia (20.8%), ventricular tachycardia (16.7%), and atrioventricular re-entrant tachycardia or atrioventricular nodal re-entrant tachycardia (10.4%). Pharmacologic treatment was the predominant therapy, but 70.8% of patients needed at least 1 ablation procedure. All patients demonstrated significant improvement in left ventricular ejection fraction after treatment, with most achieving at least near-normal ejection fractions in 80 days on average since presentation. In conclusion, TIC is overall a treatable condition with challenging diagnosis but generally has a favourable prognosis when diagnosed and treated appropriately. This article emphasizes the importance of considering TIC in the differential diagnosis of tachycardia in the context of reduced ventricular function, to recognize it and to enable targeted treatment initiation as soon as possible.