The Modifications of the Electrocardiogram in Chronic Pulmonary Tuberculosis

This preliminary paper contains general observations on the modifications of the electrocardiogram cases of chronic pulmonary tuberculosis.

1) The study has been continued for more than seven years on 8.000 patients. The tracings have often been repeated at intervals and have been recorded, besides the usual standard derivations like the peripheral ones according to Einthoven, the unipolar derivations of the limbs, and the unipolar precordial ones according to Wilson, also with the thoracic derivations of Condorelli and the right hand side thoracic derivations long since proposed by Di Maria.

2) The electrocardiographic research has revealed how of these 8.000 cases at least 2.850 (35,68 per cent), presented alterations in at least one of the tracings, and has allowed the division of their pathological aspects in three main groups selected with a clinical functional intent. It has not been possible to make evident an electrocardiographic pathognomonic picture for chronic pulmonary tuberculosis.

3) The multiplicity of the electrocardiographic pictures is justified by the fact that the factors generating the lesions of the cardio-vascular system in the course of the tuberculous affection, are different. The most important ones among these are represented by toxemia, anoxemia, the possible medical or surgical treatments, and the alteration of the electrolytic and immuno-biological constants of the organism.

Notes on the Condorelli and Di Maria methods

The precordial derivations, called "right side thorax derivations" by Di Maria, are obtained in the following way: the first, putting on the right hand margin of the second section, one electrode attached to the lead normally used for the right arm, and on the IV section, always on the same line, a second electrode attached to the lead of the left arm (commutator in D1); the second, putting on the second section the electrode attached to a lead of the right arm and on the left leg the lead normally reserved to this limb (commutator in D2); the third, putting the electrode of the left arm on the right margin of the IV section and leaving the one of the left leg on the original spot (commutator in D3).

The regulating is made with the usual voltage of 1 cm = 1 mV.

The derivations according to Condorelli, which are called "equatorial derivations," are two: 1) the right side equatorial derivation in which the electrode of the left arm is put on the section of the right median axillary line, and the electrode of the right arm on the left sub-clavicular region; 2) the left side equatorial derivation, in which the electrode of the right arm is put on the right sub-clavicular region and the electrode of the left arm is put on the left median axillary line on the VIII section.