The electrocardiographic diagnosis of right ventricular hypertrophy.

Abstract 1. 1. The electrocardiographic criteria for the diagnosis of right ventricular hypertrophy have been evaluated and elaborated upon through a critical review of the literature and a study of our clinical and autopsy material. A detailed description is given of the findings in the standard limb leads, the Wilson precordial leads, and the Goldberger unipolar extremity leads. 2. 2. An analysis is presented of all of our cases of patients in whom Leads V 1 through V 6 , inclusive, and the standard limb leads were obtained during life and a diagnosis of preponderant hypertrophy of the right ventricle was established at autopsy. The series comprised a total of forty cases. The augmented unipolar limb leads were available in thirty-five of the cases and Lead V 3R in eight. The amplitude of each deflection of the QRS in V 3R , V 1 , V 2 , V 5 , V 6 and aV R was measured and the time interval from the onset of QRS to (1) the nadir of Q, (2) peak of R, (3) nadir of S, (4) peak of R′, and (5) end of QRS was determined in each of these leads with the aid of a Cambridge measuring device. In thirtysix of the patients post-mortem study included injection of the heart with a radiopaque mass, subsequent roentgenogram, and careful dissection. 3. 3. The forty cases of patients proven to have preponderant right ventricular hypertrophy at autopsy were classified according to electrocardiographic pattern into the following six groups: 3.1. (A) Pattern in Leads V 1 through V 6 , inclusive, was considered diagnostic of right ventricular hypertrophy in thirteen cases on the basis of the following criteria: (1) reversal in the ratio of the amplitudes of the R and S waves in V 1 and V 6 characterized by an abnormally large R in proportion to S in V 1 , a diminution in ratio in leads further to the left, and a prominent S in V 6 ; (2) time interval from beginning of QRS to onset of intrinsicoid deflection that was abnormally long in V 1 (generally between 0.03 and 0.05 second) and greater than in V 5 or V 6 ; (3) tendency to a small Q wave in V 1 ; (4) tendency to inversion of the T wave in V 1 and to upright T wave in V 6 ; (5) total duration of QRS less than 0.12 second and generally within the normal range; (6) absence of notching or double peaking of the R wave of V 1 , except in one case where bundle branch block could be excluded and a conduction defect in the outer wall of the right ventricle postulated from the presence of a Q wave followed by a notched R in all leads from the right side of the precordium. The electrocardiographic findings were similar, irrespective of the cause of the right ventricular hypertrophy. 3.2. (B) Pattern typical of right ventricular hypertrophy was present in Lead V 3R , but not in V 1 or V 2 in one patient, and signs of incomplete right bundle branch block were distinctive in V 3R , but not in V 1 or V 2 of another patient. 3.3. (C) Pattern presumptive of right ventricular hypertrophy was present in Lead V 6 and aV R in six patients without confirmatory signs in V 1 or V 2 . This pattern consisted of an abnormally large S wave in V 6 together with an abnormally tall R in aV R , which was four to ten times the amplitude of the downward deflection in the same lead. If additional leads had been taken over the right precordium, it is probable that the diagnosis of right ventricular hypertrophy could have been definitely established in some of these cases. 3.4. (D) Incomplete right bundle branch block was present in nine patients, the diagnosis being established by the following criteria: (1) in leads from the right side of the precordium, the R wave was prominent and exhibited either a course notch or double peak and S wave was small or absent, whereas, in leads further to the left, S wave was deeper and broader: (2) time interval from beginning of QRS to onset of intrinsicoid deflection in V 1 that was generally between 0.05 and 0.075 second and exceeded that in uncomplicated right ventricular hypertrophy; (3) total duration of QRS that was less than 0.12 second and usually between 0.09 and 0.11 second; (4) absence of Q wave in leads from the right side of the precordium. The electrocardiographic pattern of incomplete right bundle branch block was more or less stereotyped, irrespective of the cause of the right ventricular hypertrophy. 3.5. (E) Complete right bundle branch block was present in three cases, as indicated by the following criteria: (1) in leads from the right side of the precordium the R wave was prominent and either coarsely notched or double peaked, Q was absent, and S was small or absent; (2) total duration of QRS was 0.12 second or longer. Neither complete nor incomplete right bundle branch block are pathognomonic of right ventricular hypertrophy. 3.6. (F) Pattern in the precordial and unipolar extremity leads was not diagnostic of either hypertrophy or a conduction defect in the right ventricle in seven cases. One of these patients, who had an R′ deflection in V 3R and V 1 which was thought to have been derived from the posterobasal surface of the left ventricle, is discussed in detail. 4. 4. The presence of right axis deviation in the standard leads accompanied by depression of RS-T 2 and RS-T 3 and inversion of T 2 and T 3 is not diagnostic of right ventricular hypertrophy, as shown by previous workers and confirmed by our autopsy material. This pattern may occur in left ventricular hypertrophy and even in normal subjects when the heart is in vertical position.