Nomenclature and description of the electrocardiogram

In view of the present confusion regarding the terms to be applied to the peaks of the electrocardiogram, the usage of Einthoven and of Lewis has been reviewed in the hope of finding a reasonable solution. Lewis' modification of Einthoven's terminology is recommended.Suggestions are made for naming the peaks of certain types of QRS not particularly mentioned by Lewis, namely, the M complex, the vibratory QRS, and the solely downward deflection.A method of describing notching and slurring of QRS is outlined, and certain features of the measurement of the duration of P, QRS, and Q-T are emphasized.A definition of the term diphasic is suggested, to be applied to the P and T waves; also, a method of describing these waves which is considered adequate for statistical grouping is presented.