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Effect of the Air Volume in the Lung on Electrocardiogram : Experimental Studies on the Genesis of Electrocardiographic Changes in Pulmonary Emphysema

1969; Japanese Circulation Society; Volume: 33; Issue: 10 Linguagem: Inglês

10.1253/jcj.33.1193

1347-4839

Akira Okada,

Refrigeration and Air Conditioning Technologies

Since the detailed study was reported by ZUC-KERMANN and others, many authors have de-scribed some variations in the patterns of QRS complexes which were characteristic of the electrocardiograms of pulrnonary emphysema. But few experiments have been tried yet to investigate the genesis of these electrical changes manifested on electrocardiograms. It is the purpose of this study to investigate the role of decreased conductivity of the lung in the genesis of the changes in the QRS patterns which are characteristic of the electrocardiograms of pulmonary emphysema. For this purpose, an attempt was made in this experiment to analyze quantitatively changes in the QRS patterns and in the magnitude of lead vectors resulted from increased air volume in the lung. Method: Seventy-three mongrel dogs weighning about 10kg were used for this experiment. After anesthetization the chest of the dog was opened by midsternal thoracotomy under artificial positive pressure breathing. The heart holder which had to make the heart fix in the thorax was inserted either into the anterior or the posterior wall of the ventricle. The two-directional artificial dipole was attached to near the tip of this heart holder. In case of twelve dogs the dipole was located in the anterior wall and nine dogs in the posterior wall. About ten unipolar electrodes for recording of epicardial electrograms were attached to all around the epicardium in some experiments. After the chest was closed the intrapleural pressure was controled at the level of -3 to -7 cm H2O by means of the continuous aspiration. Scalar electrocardiograms of MCFEE-PARUN-GAO lead system and in some experiments epicardial electrograms were recorded with a photo-corder. Also in some cases vectorcardiograms of MCFEE-PARUNGAO lead system were recorded with three cathode ray oscilloscopes. In some experiments epicardial electrograms and MCFEE-PARUNGAO lead electrocardiograms were recorded simultaneously. The artificial dipole was energized into three orthogonal directions in turn (X, Y and Z axes) with 20 HZ AC through the oscillator during the diastolic phase of the cardiac cycle. To energize into Y direction, X directional dipole was rotated in the myocardium so far as 90 degree around the heart holder. The strength of the current with which the dipole was energized was controled so as not to induce runs of ventricular premature beats. The voltages corresponding X, Y and Z components of the lead vector produced by this dipole were also recorded with a photocorder.