Insights on Atrial Electrocardiogram in Sinus Rhythm and Atrioventricular Block for Improved Clinical Diagnosis

Abstract

Objective: This study aims to characterize P and Ta wave of Modified Limb Lead (MLL) Electrocardiogram (ECG) in Normal Sinus Rhythm (NSR) and Atrioventricular Block (AVB). Methods: ECGs were recorded using MLL configuration from 100 NSR volunteers (mean age 31 years, 35 women) and 20 male AVB patients (mean age 72 years). Amplitudes and durations of P, Ta wave, and PTa Interval (PTaI) were measured, plotted, and analyzed for both the groups. Results: P-wave amplitudes were larger in AVB, and also P, Ta waves correlated significantly in both groups with higher correlation in AVB (NSR: [Formula: see text]; AVB: [Formula: see text]). Ta-wave duration ([Formula: see text] ms) was longer than P-wave duration ([Formula: see text] ms) in AVB patients and was opposite to P-wave polarity in all the leads. PP Interval (PPI) correlated significantly with P wave (NSR: [Formula: see text]; AVB: [Formula: see text]), Ta wave ([Formula: see text]; [Formula: see text]), PTaI ([Formula: see text]; [Formula: see text]), and corrected PTaI ([Formula: see text]; [Formula: see text]). Conclusion: P-wave right axis shift leads to the higher P-wave amplitude in AVB which may be due to the advancing age and atrial chamber enlargement. In NSR, the duration of observable Ta wave was longer than P wave, whereas in AVB, the Ta wave duration was 3–3.5 times longer than P wave.

Exaggerated amplitude and peak location of Ta wave in tachycardia as an indicator for atrial disorders

“…Therefore, it is timely to study its characteristics in detail. [8] studied the characteristics of Ta and P waves in the atrioventricular condition and determined that amplitudes change more compared to the change in duration parameters in disease conditions. Another study [10] determined that increased heart rate in ST condition leads to axis shift of the waves and the change in amplitude.…”

“…A study [6,7,8] employed a novel Modified Limb Lead (MLL) ECG system and noted the 'observable Ta wave' in Sinus Rhythm (SR) of duration 109 ± 4.7 ms. Hence, the MLL system also employed in this study helps to witness and measure the Ta wave features by comparing the P-R and S-T segment amplitude for the Sinus Rhythm (SR) and Sinus Tachycardia (ST) ECG recordings which may assist in the early determination of disease.…”