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Concealed rhythms by double ventricular parasystole
1DST Centre for Visceral Mechanisms, V.P. Chest Institute, University of Delhi, India.
Insights
This study analyzed electrocardiograms of patients with ventricular ectopic rhythms, revealing concealed rhythms and double ectopic beats. These findings suggest bifocal automaticity may cause bidirectional ventricular tachycardia.
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.
Abstract:
Electrocardiograms taken from 11 patients in sinus rhythm with ventricular ectopic rhythms from two different foci were analyzed to find the number of sinus beats, S, between the ectopic rhythms (S values). Three out of 11 patients had the S values typical for concealed ectopic rhythms. One of them had concealed bigeminy of 2n-1 form that occasionally shifted to 2n form. Following the shift, S values of 2n-1 form were always achieved by the occurrence of double ventricular ectopic rhythms in succession. Concealed trigeminy of 3n and 3n-2 form was seen in the other two patients. Double ventricular ectopic rhythms had bizarre abnormal QRS complexes of two different morphologies and were inscribed in opposite directions. Ectopic rhythms in each case had parasystolic characteristics. These observations suggest bifocal automaticity as a mechanism for bidirectional ventricular tachycardia.