ABSTRACT
The height of the R wave and depth of the S wave vary from lead to lead in the normal electrocardiogram (ECG). There are many criteria for the ECG diagnosis of left ventricular hypertrophy, with varying sensitivity and specificity. Generally, the diagnostic criteria are quite specific, but not sensitive. The Romhilt–Estes scoring system allocates points for the presence of certain criteria. A score of 5 indicates left ventricular hypertrophy and a score of 4 indicates probable left ventricular hypertrophy. Infarction of the posterior wall of the left ventricle leads to reciprocal changes when viewed from the perspective of the anterior chest leads. Acute myocardial infarction is a medical emergency. Prompt diagnosis and treatment are essential. Small QRS complexes indicate that relatively little of the voltage generated by ventricular depolarization is reaching the ECG electrodes. Although criteria exist for the normal upper limit of QRS complex size, there are no similar guidelines for the lower limit of QRS size.
