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Optimal QT/JT interval assessment in patients with complete bundle branch block
John Chiladakis1, Andreas Kalogeropoulos, Nikolaos Koutsogiannis
1Cardiology Department, Patras University Hospital, Rion, Patras, Greece. chil@otenet.gr
Summary
Assessing QT/JT intervals in bundle branch block (BBB) is crucial for arrhythmia risk. The Hodges, Nomogram, and Framingham formulas offer the most reliable heart rate correction, unlike Bazett's formula which exaggerates variations.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Prolonged ventricular repolarization increases malignant ventricular arrhythmia risk.
- Accurate QT/JT interval assessment is vital in patients with bundle branch block (BBB).
Purpose of the Study:
- To determine the optimal method for assessing QT/JT intervals in patients with complete bundle branch block (BBB).
Main Methods:
- Seventy-one dual-chamber device recipients with baseline left or right BBB were studied.
- QT/JT intervals were recorded at varying heart rates (51-100 bpm) with six correction formulas.
- Linear mixed-effects models analyzed heart rate's effect on corrected QT (QTc) and JT (JTc) intervals.
Main Results:
- Heart rate significantly affected QTc and JTc intervals across all formulas (P < 0.001).
- Hodges, Nomogram, and Framingham methods showed the least variability in QTc/JTc measurements.
- Bazett's formula resulted in the most pronounced interval variations in patients with BBB.
Conclusions:
- Hodges, Nomogram, and Framingham correction methods are recommended for QT/JT interval assessment in BBB.
- Bazett's formula overestimates heart rate dependency of ventricular repolarization intervals in BBB.
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