Abstract Body (Do not enter title and authors here): INTRODUCTION
Asynchronous ventricular pre-excitation over an accessory pathway (AP) in the absence of tachyarrhythmia is sometimes reported to cause left ventricular dysfunction (LVD).
AIMS
To analyze the pathophysiological mechanism, role of AP location, evaluation modalities, and management of pre-excitation-related LVD.
METHODS
PubMed and Google Scholar databases were searched for reports on pre-excitation-induced LVD regardless of patient's age, and publication date.
RESULTS
Out of 11,775 citations retrieved, 53 met inclusion criteria, including 41 case reports and 12 observational studies with 611 total participants, age range of 1.14-60.8 years, and M: F of 325:265 (Table). At initial presentation, acute HF was common in pediatric patients, with poor response to medical therapy; while adults were more often asymptomatic. Right septal and right free wall were the commonest APs location associated with LVD. Amiodarone and propafenone achieved improvement in HF status by causing AP block and restoring ventricular synchrony in pediatric patients deemed unfit for catheter ablation (CA). Septal dyskinesia (SD) and intra-LV dyssynchrony (ILVD) were the key pathophysiological mechanisms causing LVD, leading to regional myocardial wall thinning and hypotrophy. Two-dimensional strain echocardiography (2D-STE) was used in quantifying regional myocardial strain, noninvasive localization of APs, and assessing therapeutic response to CA. Systolic intervals ratio [(pre-ejection period (PEP)/LV ejection time (LVET)] assessed via continuous Doppler detected derangement in LVEF with high accuracy. Preexcitation-induced myocardial changes were usually reversible after CA of APs with recovery of LV function. However, irreversible myocardial tissue damage even after CA was reported, especially in adults. Resolution of ILVD and SD in the immediate post-CA period was predictive of response to CA.
CONCLUSIONS
We report the largest aggregation of data regarding preexcitation-induced LV dysfunction. Long-term asynchronous activation of the LV via an AP, even without tachyarrhythmias, can causes adverse myocardial changes leading to cardiac dysfunction, especially in children with right-sided APs. 2D-STE and systolic intervals (PEP/LVET) are efficient tools for evaluation. Ablation of APs usually restores cardiac function largely; however, irreversible myocardial fibrosis can ensue. Based on these data, early CA of the APs associated with LV dysfunction is, therefore, recommended.