Concealed rhythms by double ventricular parasystole.

Area of Science:

• Cardiology
• Electrophysiology
• Cardiac Arrhythmias

Background:

• Ventricular ectopic rhythms can originate from multiple foci.
• Concealed ectopic rhythms are challenging to diagnose and understand.
• Bidirectional ventricular tachycardia is a serious arrhythmia.

Purpose of the Study:

• To analyze electrocardiograms (ECGs) from patients with sinus rhythm and ventricular ectopic rhythms from two foci.
• To investigate the characteristics of concealed ectopic rhythms and their relationship with sinus beats.
• To explore the underlying mechanisms of bidirectional ventricular tachycardia.

Main Methods:

• Analysis of ECGs from 11 patients with sinus rhythm and ventricular ectopic rhythms.
• Quantification of sinus beats (S values) between ectopic rhythms.
• Identification of different forms of concealed bigeminy and trigeminy.
• Morphological analysis of QRS complexes during double ventricular ectopic rhythms.

Main Results:

• Three out of 11 patients exhibited S values typical for concealed ectopic rhythms.
• One patient showed concealed bigeminy (2n-1 form) that shifted to 2n form, associated with double ventricular ectopic rhythms.
• Two patients displayed concealed trigeminy (3n and 3n-2 forms).
• Double ventricular ectopic rhythms presented with distinct QRS morphologies and opposite directions, indicating parasystolic characteristics.

Conclusions:

• Concealed ectopic rhythms and double ventricular ectopic beats are observed in patients with multifocal ventricular ectopy.
• The findings support bifocal automaticity as a potential mechanism for bidirectional ventricular tachycardia.