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Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
The ECG lead I paradox in cardiac resynchronization therapy
Berry M Van Gelder1, Frank A Bracke
1Department of Cardiology, Catharina Hospital, Eindhoven, The Netherlands. carlgr@cze.nl
Pacing and Clinical Electrophysiology : PACE
|December 11, 2008
Summary
Cardiac resynchronization therapy (CRT) pacing can rarely cause paradoxical QRS complex changes in lead I. This phenomenon, observed in specific right ventricular (RV) and left ventricular (LV) lead placements, impacts pacing effectiveness.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Cardiac resynchronization therapy (CRT) relies on QRS complex morphology to guide pacing site selection and optimize stimulation effectiveness.
- Understanding QRS morphology is crucial for successful CRT device implantation and patient outcomes.
Observation:
- A review of 737 patients with CRT devices identified four cases exhibiting a paradoxical QRS complex in lead I.
- These patients showed a negative QRS in lead I during right ventricular (RV) pacing and a positive QRS during left ventricular (LV) pacing.
- Specific lead placements were noted: RV lead in the high septum and coronary sinus leads in posterior/postero-lateral basal regions.
Findings:
- High septal RV pacing can rarely result in a negative QRS complex in lead I.
- Basal LV lead positions may lead to a positive QRS complex in lead I during LV pacing.
- The 'lead I paradox' is evident when these unrelated phenomena coexist in a single patient.
Implications:
- This rare QRS complex behavior in lead I during CRT may necessitate careful ECG interpretation.
- Awareness of these specific lead placements and their associated ECG findings can aid in troubleshooting and optimizing CRT.
- Further investigation into the mechanisms underlying this paradoxical response could refine CRT programming and patient selection.
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