Implications for the Employment of Quantitative Electrocardiography in Research and Clinical Applications

In ECG syndrome has been reported that associated the development of peripheral edema of varying etiology with a decrease in the body surface QRS potentials involving all ECG leads. In that work, we employed the sum of QRS complexes of 12-lead ECGs from routine daily tracings, which were obtained by our technicians without the aid of marking of the thoracic wall to ensure intrasubject reproducible recordings from the precordial ECG sites. It is common knowledge that precordial ECGs display considerable intraindividual variation stemming from an alteration in the use of thoracic landmarks for V1-V6 recording, and that even a slight change of the recording sites can alter significantly the ECG waveforms. This problem remains without solution, despite the clear treatment of the topic on the appropriate recording of the precordial ECG provided by the ECG textbooks. In practice, this is of immense importance, since such inconsistencies frequently lead to erroneous diagnoses and a need for a cardiologic consultation.

Since the six standard (bipolar and unipolar) limb ECG leads are not subject to the vagaries of inconsistent recording that is inherent with the six precordial leads, it was hypothesized that the correlation of the weight (W) gain with a reduction in the sum of the QRS complexes from the six standard ECG leads (2QRS6) in our patients with anasarca (AN) would be better than the one we found with the employment of the 2QRS12 (r = 0.61; p = 0.0005) in our previous article.

Most modern ECG machines record only leads 1 and 2, and they calculate in real time the remaining limb leads. Accordingly, it was hypothesized that using merely the sum of QRS complexes of leads 1 and 2 (2QRS2) from a recorded 12-lead ECG will suffice to provide at a glance a quick index of body fluid retention. Such an index could be used at bedside for the evaluation of patients with an edematous state, thus obviating the inconvenience of calculating 2QRS6 or 2QRS12.

Consequently, the database of our previous study in conjunction with 2QRS6 and 2QRS2 in addition to the corresponding 2QRS12 used previously, was employed to investigate the two hypotheses cited above. In addition, similar ECG data from another recent study of three patients with idiopathic dilated cardiomyopathy who were admitted to the hospital with congestive heart failure (CHF) were included.

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