Exaggerated Amplitude and Peak Location of Ta Wave in Tachycardia as an Indicator for Atrial Disorders

In Standard 12-Lead Electrocardiogram (ECG) of Sinus Rhythm (SR) volunteers, the atrial repolarization (Ta wave) as a possible indicator for atrial-related diseases is undermined. The presence of Ta wave in exercise stress ECG has been noted previously, however its manifestation during SR is limited in Standard 12-lead system. This study delineates and compares the characteristics of the Ta wave in Sinus Tachycardia (ST) with the SR in terms of amplitude and Ta peak location using the Modified Limb Lead (MLL) system. MLL was recorded for eight SR and fifteen ST volunteers (mean age of 24 years). P-R and S-T segment amplitudes were measured and analyzed. Ta wave-related impact on P-R and S-T segment have been noted and found a 41.60 % increase in
$P-R_{ST}$
to
$P-R_{SR}$
and 49.60% in
$S-T_{ST}$
to
$S-T_{SR}$
using absolute values of P-R and S- T segments. Moreover, the Ta wave peak can be predicted with the change in morphology of the P-R and S-T segments. Determination of Ta wave peak may help to delineate atrial-related disease conditions. A detailed study on Ta wave induced S- T segment depression and elevation helps decrease the false-positive detection of myocardial ischemia and infarction.