Historically, electrocardiographic criteria for right ventricular (RV) hypertrophy has achieved high specificity but low sensitivity. Recently, however, Butler-Leggett et al. have introduced three criteria that attained a 66% sensitivity in a population with RV hypertrophy due to mitral stenosis while maintaining a 95% specificity in an extensive normal control group. Electrocardiographic diagnosis of RV hypertrophy is principally dependent on changes in the QRS complex that may be masked or mimicked by myocardial infarction (MI). This dilemma has been confirmed by documentation of the low specificity of both the Selvester QRS scoring system for MI size estimation (greater than 3 points) and its screening subset (greater than 0 points) in a pure mitral stenosis population. This study introduces the population characterized by RV hypertrophy due to cor pulmonale, which has a mean pulmonary arterial systolic pressure that is higher than the mean for the mitral stenosis population and consequently suggests more severe RV hypertrophy. When compared, the Butler-Leggett criteria for RV hypertrophy are more sensitive in the new population than in the mitral stenosis population (89% versus 60%) and the Selvester QRS scoring system is less specific (12% versus 60%). Three sequential steps are suggested for electrocardiographic analysis: (1) diagnosis of RV hypertrophy using the Butler-Leggett criteria, (2) diagnosis of MI using the Selvester screening criteria in those patients with step 1 negative, and (3) estimation of MI size using the complete Selvester scoring system in patients with step 1 negative and step 2 positive.