Author + information
- Behzad B. Pavri,
- Henry Siu,
- Effie Andrikopoulou,
- Reginald Ho and
- Matthew DeCaro
The normal (NL) T wave in health is asymmetric [gentler initial slope (TInit Sl), steeper terminal slope (TTerm Sl)]. The T Peak – T End (TP-TE) interval reflects repolarization dispersion; a prolonged QTc (LQT, Bazett) is associated with TP-TE prolongation and increased arrhythmic risk. We evaluated automated T wave TInitSl and TTermSl measurements (mV/ms) from NL and LQT ECGs as novel measures of repolarization dispersion.
An automated formula was devised to calculate TInit Sl and TTerm Sl from digital ECGs using the lead with the tallest/deepest T wave. The slope of the best-fit tangent was calculated for 50 – 90% of TInit Sl and for 20 – 90% of TTerm Sl. Absolute values of TInit Sl & TTerm Sl, absolute slope difference ([TTerm Sl]-[TInit Sl]), & TP-TE intervals were automatically generated. NLs were identified by NL echo and NL ECG. LQT ECGs were selected by QTc >500 of any etiology; all heart rates were between 50 – 90 bpm.
100 NL, 186 LQT ECGs were analyzed (Table). All T wave slope measurements and TP-TE were significantly different between NL and LQT ECGs. TTerm Sl ≤5 was seen in 5/100 NLs and 76/186 LQT ECGs, Spec=95%, PPV=94%, P<0.001.
Automated T wave slopes are significantly different in NL vs. LQT ECGs. Mean TP-TE intervals were <17 ms different, highlighting difficulty in measurement. T wave slope, a novel automated method of assessing repolarization dispersion, may be less prone to measurement error and may be useful in identifying arrhythmic risk in various disease states.
|NL (n=100)||LQT (n=186)||P Value|
|Initial T Wave Slope (mV/ms)||8.00||5.75||<0.001|
|Terminal T Wave Slope (mV/ms||10.70||7.06||<0.001|
|Slope Difference (Terminal – Initial)||2.70||1.31||<0.001|
|T Peak – T End||106.59||123.29||<0.001|
NL=Normal ECGs, LQT=ECGs with QTc>500 ms
Moderated Poster Contributions
Sunday, March 30, 2014, 9:45 a.m.-10:00 a.m.
Session Title: ECG and Stress Testing: Predictive Value
Abstract Category: 27. Standard ECG, Stress Testing: ECG, Stress Testing, Sports and Exercise
Presentation Number: 1205M-366A
- 2014 American College of Cardiology Foundation