Unraveling Myocardial Mass: Using Classical ECG With Contemporary GWAS.

I n the early 20th century, the Dutch physiologist Willen Einthoven stated “What you or I think is not important. What is important is the truth.” Today, this concept remains pertinent to our efforts to better understand myocardial mass complexity. Einthoven’s 1906 paper “Le télécardiogramme” presented the first collection of abnormal human electrocardiograms (ECGs) using the string galvanometer, which was the first published identification of abnormal ventricular cavity growth through cardiac signal recording (1). In 1914, Lewis investigated an autopsy series and reported the first use of bipolar leads voltage criteria to diagnose ventricular hypertrophy (2). His (RI RIII) þ (SI SIII) index had a maximum normal value of 1.79 mV and primarily reflected axis deviation to the left. In the mid-1940s, Wilson introduced precordial unipolar leads, enabling a better approach to estimating left ventricular mass on the basis of QRS voltage. In 1949, Sokolow and Lyon (3) published their famous summation voltage criteria (sum of R in V5 and S in V1 >3.5 mV), which were widely used over the following decades. The Romhilt-Estes criteria were published in 1968 but were less commonly employed, possibly due to their greater complexity, using a scoring system that considered QRS voltage data, ST-segment deviation, P-wave morphology, left axis deviation, and QRS duration (4). Utilization of voltage criteria peaked in 1982 with the paper by