Unusual ventricular activation produced by temporary transvenous cardiac pacing: electrovectorcardiographic findings

Area of Science:

• Cardiology
• Electrophysiology
• Medical Case Study

Background:

• Complete heart block (CHB) is a cardiac conduction system disorder leading to total electrical dissociation between atria and ventricles.
• CHB commonly causes symptoms like bradycardia, hypotension, fatigue, hemodynamic instability, syncope, and Stokes-Adams syndrome.
• Ventricular escape rhythms in CHB can originate from various points in the conduction system, influencing QRS width and heart rate.

Observation:

• A middle-aged male patient presented with severe bradycardia (34 bpm) and progressive fatigue.
• A temporary pacemaker was implanted in the subtricuspid region to manage the CHB.
• The post-intervention electrocardiogram exhibited atypical characteristics.

Findings:

• Escape rhythms originating above the His bundle bifurcation typically yield narrow QRS complexes and a faster heart rate, unless His system disease is present.
• The specific electrocardiogram features observed post-pacemaker implantation in this CHB case were unusual and warrant further investigation.
• This case highlights the variability in electrocardiographic presentations of CHB and the impact of pacemaker intervention.

Implications:

• Understanding the origin of ventricular escape rhythms is crucial for interpreting electrocardiograms in CHB patients.
• The unusual post-intervention ECG findings suggest potential complexities in cardiac pacing or conduction abnormalities.
• Further analysis of this case may refine diagnostic and therapeutic strategies for complete heart block and temporary pacemaker management.