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The retrograde His bundle deflection: its recognition and value in the analysis of tachyarrhythmias induced by
Insights
His bundle electrocardiography aids in understanding ectopic beats and tachycardias. Retrograde His deflections help exclude certain reentry mechanisms, especially in bundle branch block patients.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Interpreting His bundle deflections requires considering simultaneous intracardiac and surface lead recordings.
- Understanding ectopic beats and tachycardias is crucial in cardiac electrophysiology.
Purpose of the Study:
- To evaluate the utility of His bundle electrocardiography in analyzing ectopic beats and tachycardias.
- To differentiate reentry mechanisms using His bundle recordings.
Main Methods:
- His bundle electrocardiography with simultaneous intracardiac and surface lead recordings.
- Premature ventricular stimulation during the T wave.
- Recording coronary sinus and low lateral right atrial electrograms when necessary.
Main Results:
- His bundle electrocardiography is useful for analyzing ectopic beats in patients without coronary artery or myocardial disease.
- AV nodal echoes and reciprocating tachycardias were identified in patients with and without preexcitation.
- Retrograde His deflection behavior helped exclude bundle branch reentry in some cases, particularly with contralateral bundle branch morphology in bundle branch block.
Conclusions:
- His bundle electrocardiography is a valuable tool for analyzing complex arrhythmias.
- The retrograde His deflection's behavior is informative for excluding specific reentry circuits.
- Further electrophysiological studies may be needed for complete mechanism elucidation in certain cases.
Abstract:
Interpretation of deflections presumably retrograde His bundle in origin has to be performed in context considering the coexisting changes in simultaneously recorded intracardiac and surface leads. His bundle electrocardiography thus conceived is helpful in the analysis of the runs of ectopic beats elicited by premature ventricular stimulation during the antecedent T wave in patients without coronary artery or primary myocardial disease. Identification of AV nodal echoes within the paroxysms as well as the subsequent runs of reciprocating tachycardias, was possible in patients with and without preexcitation, although a thorough study of these cases also requires recording of coronary sinus and low lateral right atrial electrograms. The behavior of the retrograde H deflection in respect to the first extra beat following the premature QRS complex helped in excluding bundle branch reentry. The latter is improbable in patients with 'complete' bundle branch block pattern, if extra beats show a contralateral bundle branch morphology. However, in absence of bundle branch block, retrograde H deflections were not helpful in elucidating the mechanisms of pacemaker-induced intraventricular (bundle branch, fasicular or vulnerability-related) reentry.