[Adverse effects of type B ventricular pre-excitation on ventricular wall motion and left ventricular function:...

Area of Science:

• Cardiology
• Electrophysiology
• Pediatric Cardiology

Background:

• Type B ventricular pre-excitation is associated with accessory pathways (APs) that can affect cardiac function.
• Understanding the adverse effects of these APs on ventricular mechanics and function is crucial for patient management.

Purpose of the Study:

• To investigate the impact of type B ventricular pre-excitation on ventricular wall motion and left ventricular function.
• To analyze the clinical characteristics and outcomes of patients with type B ventricular pre-excitation undergoing ablation.

Main Methods:

• Analysis of clinical, electrophysiological, and echocardiographic data from 9 pediatric patients (ages 3-16) with type B ventricular pre-excitation before and after radiofrequency catheter ablation (RFCA).
• M-Mode echocardiography was used to assess left ventricular contraction and wall motion abnormalities.

Main Results:

• All patients exhibited dyssynchronous left ventricular contraction, with some showing septal thinning and aneurysmal bulging.
• Successful RFCA was achieved in all cases, with accessory pathways located on the right-sided anteroseptum or free wall.
• Significant improvement in physical activity, growth, and cardiac function (synchronous contraction, normalized LVEF, reduced LVED) was observed post-ablation, particularly in those with coexisting dilated cardiomyopathy (DCM).

Conclusions:

• Overt right-sided accessory pathways can adversely affect ventricular function and potentially lead to dilated cardiomyopathy.
• Dyssynchronous ventricular contraction appears to be a key mechanism underlying these adverse effects.
• Radiofrequency catheter ablation is an effective treatment for these conditions, offering a good prognosis.