T-wave alternans in LQTS: repolarization-rate dynamics from digital 12-lead Holter data
K Brockmeier1, I Aslan, T Hilbel
1Department of Pediatric Cardiology, Children's University Hospital of Heidelberg, Germany. konrad_brockmeier@med.uni-heidelberg.de
Journal of Electrocardiology
|January 10, 2002
Summary
T-wave alternans (TWA), a marker of heart vulnerability in Long QT Syndrome (LQTS), was found in 3 of 18 patients. High heart rates, not rate changes, preceded TWA episodes, complicating risk management.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Diagnostics
Background:
- T-wave alternans (TWA) is a significant predictor of ventricular arrhythmias and sudden cardiac death in patients with Long QT Syndrome (LQTS).
- Accurate detection of TWA is crucial for risk stratification and management of LQTS patients.
Purpose of the Study:
- To investigate the occurrence and characteristics of T-wave alternans in a cohort of patients diagnosed with Long QT Syndrome.
- To explore the relationship between TWA, heart rate variability, and sudden cardiac death in LQTS patients.
Main Methods:
- Digital Holter ECG analysis was performed on 18 LQTS patients (ages 6 months to 32 years).
- Specialized software was used to analyze cycle length-mediated repolarization dynamics and detect TWA.
- Morphological expression and triggers of TWA, including heart rate and ventricular premature beats, were assessed.
Main Results:
- Macroscopic T-wave alternans was identified in 3 out of 18 LQTS patients.
- TWA onset was associated with long/short RR interval sequences and heart rates exceeding 130-140 bpm.
- Two patients with detected TWA experienced sudden cardiac death during follow-up.
Conclusions:
- T-wave alternans is present in a subset of LQTS patients and may indicate a high risk for sudden cardiac death.
- Current automated Holter ECG analysis may miss TWA, potentially leading to underestimation of risk.
- High heart rates, rather than beat-to-beat rate variability, appear to be the primary trigger for TWA in LQTS, posing challenges for therapeutic strategies.
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