Limb Lead Research Articles

The distinctive electrocardiogram of Duchenne's progressive muscular dystrophy: An electrocardiographic-pathologic correlative study

The clinical, electrocardiographic, hemodynamic and cardiac pathologic features are described in two patients with the rapidly progressive, pseudohypertrophic, sexlinked form of Duchenne's muscular dystrophy. Previous studies have shown that the electrocardiogram is distinctive enough to aid in identifying this particular type of heredofamilial myopathic disorder even when the clinical features of the systemic myopathy are inconclusive. Tall right precordial R waves and deep limb lead and left precordial Q waves characterize these electrocardiograms. Information thus far has not provided explanations for either the distinctive morphology of the Duchenne electrocardiogram or for the variety of rhythm disturbances that have been observed. Accordingly, an electrocardiographic-pathologic correlative study was undertaken in order to determine whether a relationship existed between the distribution of myocardial dystrophy, the presence of an unusual type of small vessel coronary arteriopathy, and the electrocardiographic abnormalities of both QRS configuration and rhythm. The present study indicates that the anterior shift of the QRS (tall right precordial R waves) relates to a loss of posteriorly directed electrical forces caused by selective scarring of the posterobasal portion of the left ventricle. The abnormally deep Q waves appeared to reflect lateral extension of this scarring. These areas of myocardial fibrosis corresponded precisely to the locations of altered electrical activity demonstrated by the electrocardiogram. The reason for this unusual focal location of myocardial fibrosis was not determined. Although striking abnormalities were found in small intramural coronary arteries, the distribution of scarring was unrelated to the arteriopathy. The pathologic observations provided only scanty information regarding the rhythm disturbances. Degeneration of neurogenic fibers of the sinus or atrioventricular nodes could not be held responsible, but in one patient the arteries to both cardiac nodes were abnormal and may have contributed to the clinical arrhythmias.

ALTERATIONS IN CARDIAC SYNCHRONY INDUCED BY THE CARDIAC SYMPATHETIC NERVES.

While pressures were recorded separately from the four chambers of the heart in openchest dog preparations, together with a standard limb lead of the ECG, the right and left stellate ganglia were stimulated. Measurements from the beginning of the P wave to the initial rise in chamber pressures revealed that pressure in the left ventricle began to rise approximately 20 msec prior to that in the right ventricle. This interval was significantly shortened during electrical stimulation of the stellate ganglion. Although the interval between P wave and the initial pressure elevations in the right atrium (RA) and the left atrium (LA) both shortened during stellate stimulation, P-RA decreased considerably more than P-LA. The P wave, PR interval, and the QRS complex all shortened markedly, indicating increased conduction velocity over the atria, the nodal conducting tissue, and the ventricles during stellate stimulation. These events occurred with or without alterations in heart rate and were correlated with large increases in the rate of change of ventricular pressures. Simple algebraic summation of individual muscle segment contractions may achieve significantly greater intraventricular pressure as the contractions become more synchronous. The total pressure developed is further augmented when each individual unit contracts with greater force and greater velocity. The recruitment of additional functional units would result in further summation and thus in still greater augmentation in total force and pressure. Alterations in pacemaker site are common during stellate stimulation.

EFFECTS OF POTASSIUM ON AUTOMATICITY AND CONDUCTION OF CANINE HEARTS.

The action of potassium on cardiac automaticity and conduction was studied in dogs. It was found that idioventricular automaticity is depressed at an early stage of potassium administration. Apparent dissociation between P and QRS waves resulted from various degrees of atrioventricular block, but not complete block. The ventricles were driven by an atrial pacemaker even in absence of P waves in the limb lead ECG, as evidenced by the following findings. First, local atrial activity persisted in absence of P waves. Second, the His bundle electrogram maintained its control pattern. Finally, vagal stimulation inhibited the ventricular activity. Depression of ventricular conduction was found to involve Purkinje fibers, their junction with muscle, and the muscular fibers. Enlargement of the ventricular complexes in the ECG results in part from intermingling of depolarization and repolarization processes. Cardiac arrest results from failure of conduction since atrial activity often persisted after ventricular arrest. Ventricular flutter may occur in presence of reduced idioventricular automaticity; it is precipitated by a supraventricular beat under conditions of depressed ventricular conduction.

MECHANISM OF ATRIAL FLUTTER AND FIBRILLATION INDUCED BY ACONITINE IN THE DOG, WITH OBSERVATIONS ON THE ROLE OF CHOLINEGIC FACTORS.

The topical application of aconitine nitrate to the right atrial appendage in the "intact" anaesthetized dog produced atrial flutter. Premature systoles with fixed coupling preceded the development of flutter. In early stages of the arrhythmia, atrial rate was irregularly irregular. Also, the form of flutter beats was similar to that of preceding premature systoles. The fibrillatory activity of acetylcholine described by earlier workers has been confirmed. Transient atrial dissociation was seen after intravenous injection or topical application of acetylcholine. The occurrence of fibrillation in the left atrium after focal application of acetylcholine has been demonstrated, while the right atrial appendage containing the ectopic focus induced by aconitine continued to flutter. Aconitine produced slow-rate flutter in dogs treated with atropine or hemicholinium; this flutter was easily distinguishable from the sinus tachycardia produced by these drugs, by recording the electrocardiogram from a direct atrial lead from the area treated with aconitine, but not from limb lead II. The importance of these findings in the interpretation of the mechanism of atrial flutter and fibrillation is discussed.

AN EXPERIMENTAL STUDY OF THE ACTION OF SUXAMETHONIUM ON THE CIRCULATORY SYSTEM

SUMMARY The cardiovascular actions of suxamethonium were studied in spinal cat preparations, and in cats with intact central nervous systems anaesthetized with a thiopentone, nitrous-oxide and oxygen sequence. Mechanical artificial ventilation of the lungs was maintained throughout. Intra-arterial pressure, standard limb lead electrocardiograms and respiratory movements were recorded. Under these conditions suxamethonium was shown to have nicotine-like and muscarine-like activity. It is suggested that suxamethonium produces similar effects in other animals and in man.

Clinical studies on the brachial artery sphygmogram

The elasticity of the vascular wall has been the subject of many studies either with surgical or without surgical methods. The present author attempted to measure the elasticity of the arterial wall from the pulse wave curve recordable at the brachial artery and with a set of rather bold assumptions. Namely, the author assumed the arterial wall as a simple physical system with elasticity. Under this assumption the following equation will apply to the movement of the arterial wall: md2x/dt2=-Kx x=Sin ωt ω=2π/T T=2π√(m/K) where m : unit mass of the arterial wall tissue x : distance of the dislocation of a fixed point on the arterial wall vertical to the axis of the artery k : coefficient of elasticity T : period of sine wave The measurement of T will then allow the estimation of K, the coefficient of elasticity. Since, on the other hand, the velocity of the pulse wave propagation is related to the elasticity coefficient as follows : V∝√(p/K) there is another method of estimating the elasticity coefficient of the arterial wall. Methods Materials used consisted of three groups, (a) normal group, (b) arteriosclerotic group and (c) non-arteriosclerotic group consisting of cases with juvenile hypertension, nephritis and cardiac disease. The pulse wave was measured from the brachial artery by such arrangements that each pulse wave caused a corresponding change in the electrical capacity of the system which was presented to a condense microphone. At the same time, occlusion was applied 20cm distal to the point of the pulse wave recording by tighteing a vinyl-covered rubber band around the arm in order to measure the period of the reflected wave component (will be accentuated by occlusion) and measure the occlusion. Following this, the injection of TEAB or noradrenalin was performed and Pulse waves were recorded before and after injection (in this case, too, with and without occlusion). Throughout the course of these tests, simultaneous electrocardiograms were recorded by the third limb lead. The duration of time intervening between the R wave of electrocardiogram and the origin of ascending limb of the pulse wave gave the pulse wave arrival time. In this way the percentage change in pulse ware arrival time due to occlusion was also determined.

Graphic determination and comparison of RLF plane vector angles obtained from lead projection ratios using the Einthoven and various Burger-type triangles

The limb lead projection ratios for Lead I/Lead II, Lead I/Lead III, and Lead II/Lead III throughout the 360° of the RLF plane have been presented for the Einthoven and four representative Burger-type scalene triangular reference frames. Comparison of the angles given by the various reference systems for each lead ratio showed that, although in hearts having electrically horizontal axes all five methods of assessment gave essentially similar angular values, the vector as determined from the equilateral triangle is, in general, placed more vertically than by any of the scalene triangles. Within the range 0° to 50° the “mean” Burger triangle produced angles nearest to the Einthoven values, but in the clinically important range of 50° to 80° gave maximal differences from the Einthoven. The angular difference between QRS and T in the RLF plane is shown to be a function of the reference frame used and, consequently, should not be employed as a measure of cardiac electric longitudinal rotation unless the individual's own characteristic reference system can be determined.

Study on the Relation between the Electrocardiographic Change and the Histological Change in the Experimental Myocarditis

(II) Experimental Myocarditis The exprimental study of allergic myocarditis has been made by many scholars since olden times. But it was very difficult that allergic changes were produced in the disirable organ freely and locally. As the mechanism of allergy was made clear by Professor Maekawa's allergy theory and by a series of experiments on allergy in his laboratory, allergic inflamation has been able to be caused freely in the heart. Already a few reports on the relation between electrocardiographic changes in allergic myocarditis and its histological changes have been described. The reports chiefly stated that, in spite of remarkable histological changes, the electrocardiographic changes were very slight and the mutual-relationship was not clear. F or the purpose of knowing whether the electrocardisgraphic changes were caused by the myocarditis or not, the course of the disease was investigated with the limb-lead electracardiogram; moreover, to examine them in detail, the chest lead electrocardiogram with photographic method that was already reported was taken. Thus the relation between the histological change and the electrocardiographic change was studied.Method : 1) Antigens : By means of Kitasawa's method, cephalin and lecithin were extracted from ox myocardium. The white of an egg (2 cc/kg) which was diluted 50 % by physiological salt solution, or ox serum (2 cc/kg) were added to cephalin (2 mg/a rabbit) or lecithin (8.5 mg/a rabbit) and they were mixed fully. After they were let alone a room for an hour they were used.2) Rabbits were sensitized by intravenous injection of the above mentioned antigens for 3 days (once a day) and were reinjected by the same antigen for 3 days (once a day) 3 weeks later.At the 7th day after reinjection, rabbits were killed.3) Throughout this experiment, all rabbits were observed electrocardiographically and histological surveys were compared with electrocardiographic findings.4) Some rabbits were killed halfway and histological surveys were compared with electrocardiographic findings.Results and Conclusion : 1) When the substance, which a mixture of 50 % raw white physiological salt solution with ox cephalin or lecithin (the antigen) was used, the histological changes in heart were generally interstitial, sligth perivascular infiltration and more remarkable in the right ventricle than in the left ventricle.When the mixture of ox serum with cephalin or lecithin, was used : chiefly a remarkable perivascular myocarditis; moreover, interstitial myocarditis and endocarditis were found.In either case, the longer the time after reinjection, passes by the more marked histological cnanges were found.But the others before reinjection and after sensitization showed slight changes. When lecthin was used, no matter what the protein was, the histological changes in their heart were much slighter than in that case of cephalin.2) Generally, the electrocardiographic changes were weaker relative to the histological changes.When the histolofical changes extended to the pericardium, electrocardiographic findings were marked. Alterations of ST segment and T wave (monophasic ST, T) were registered both in the limb lead and in the chest lead.In other cases, in general, their findings were the elevation or depression of ST segment and increased, decreased, low or inverted T, etc.3) The relationship was as follows between electrocardiograms of rabbits and their histological findings of their heart.Namely, in 4 cases which were destroyed pericardium and myocardium among 19 cases of definite histological changes, the elevation of ST segment in lead I and lead II, the depression of Segmen in lead III, and the monophasic STCF3, CF4 segment and TCF3, CF4 wave in the chest lead were noted. They showed just the same electrocardiographic changes that were noted in man. [the rest omitted]

肺手術に関する心電図の臨床的研究(第2報) : 胸成術後心電図各棘の変化

The author made periodic observations of electrocardiographic variations resulting from thoracoplasty. Results obtained are given below.Methods : Methods used were just the same as those described in Report I.Results and Conclusions : Selection of cases was done as described in Report I ; that is, from 93 cases who had undergone thoracoplasty those were selected who gave abnormal electrocardiographic findings at rest or after exercise. The selected cases were electrocardiographically examined from the 2nd month after operation to the 12th.1) P-Wave : Cases with heightened PII III-waves gradually increased in number from the 2nd postoperative month, and in the 12 th month had increased by about 300 per cent. This is a peculiar phenomenon observed only after thoracoplasty.2) ST-Segment : Cases with lowered STII III-and STV5 V6-segments gradually decreased in number from the 2nd postoperative month, and in the 12th month had decreased by about 50 per cent. But those cases who had preperatively shown abnormal variations in this segment at rest or after exercise gave the same abnormal findings even 12 months after operation. That is, the number of cases with abnormalities of this kind was nearly the same before and 12 months after operation.3) T-Wave : Cases with abnormal TI-waves were rapidly reduced in number from the 2nd month after operation. But those cases who had preperatively shown abnormal TI-waves at rest remained all the same unimproved on this point even 12 months after operation. Abnormal TII III-, TV2- and TV5 V6-waves were normalized in nearly the same way as abnormal ST-segments.4) Comparison between Abnormal ST-Segments and T-Waves in Standard Limb Lead and Those in Precordial Lead : Abnormal ST-segments and T-waves in standard limb lead were compared with those in precordial lead. Results thus obtained indicated not only that myocardial damage existed in the right ventricle, as reported by various investigators, but also its presence in the left ventricle.

A vector study of the delta wave in “nondelayed” conduction

1. 1. At present, the electrocardiographic syndrome discussed could be adequately described as a “nondelayed” conduction. 2. 2. The directional incidence of the delta wave vector and remaining QRS vector, as well as the angular incidence between them at the RLF plane, were studied. The study was based on 50 limb lead electrocardiograms of “nondelayed” conduction. 3. 3. The left basal ventricular wall of either ventricle may possibly be the frequent site of the premature, weak, localized contraction associated with the delta wave vector. 4. 4. A leftward tendency of the remaining QRS activation was observed.

CHEST AND LIMB LEADS

CHEST AND LIMB LEADS

心房内刺戟伝導に関する実験的研究(第3報) : 家兎心房の刺戟伝導に就て

Using rabbit's heart unipolar leads E. C. G. were taken simultaneously over the intra vena cava superior of its initial region and the atrial surface, and calculated the time of activation arrival at different points on the atrial surface, at the same time observing the morphology of the P wave on the E. C. G. led from the surface of the atria.Summary and conclusion of this study are as follows : 1) The form of the P wave in the unipolar lead E. C. G. led from the superior cava venous appendage's angle indicated a negative wave of the QS type and the activation arrival at this point was found to be the earliest point of all on the atrial surface, which made one to assume that this region must be the initial point of activation.2) The activation arrival at points lying along the taenia terminalis from the venous appendage's angle (above mentioned) downward to the right was rapid compared with those at other points on the atrium. Moreover, the form of the P wave at these points in the unipolar lead E. C. G. was found to be of the rS type with predominance of the negativity.3) Despite the fact that the distance between each points on the surface of the right appendage and the head of the sinus node was comparatively small, the activation arrival was late, and the P wave in the unipolar lead E. C. G. taken over those points indicated the RS type.4) Inferring from above facts and the activation times at various points on the atrial surface, it is proper to acknowledge the assumption that the activation of the atrium does not propagate from the head of the sinus node in proportion to distance in diffusiveness, but is carried out through some definite formation.II. In experiments with eight rabbits, the author recorded the E. C. G. intra atrial unipolar lead and the standard limb lead II simultaneously after injuring different points at localities in the atrial wall and the atrial septum thrusting them with a pointed knife through the atrial wall or the appendage, and studied how relationships are there between the injured points and the change in the E. C. G. Various observation were made on the different injured points. Summary and conclusion of this experiment are as follows : 1) When the previous part of the fossa ovalis or wall of the appendage were injured, the heart beating remained for about 30 minutes, and besides a presumption of the results of an acute heart failure due to bleeding, no particular change was observed in the E. C. G.2) When injury was given to the upper part of the right atrium near the Bachmann's bundle, it was observed that very soon after the administering of injury changes were seen to take place, such as a marked transformation of the P wave, an irregular beating of the heart, an appearance of two P waves of entirely different kind, disturbances in the a-v conduction, etc. From these observation, it was assumed that there existed activation pathways between the sinus node and the left atrium, and between the sinus node and the Tawara's node.3) An injury given to the border between the anterior wall of the atrium and the septum often caused such changes in the E. C. G. as the shortening or prolongation of the P-Q interval, an appearance of the a-v nodal rhythm, a sudden cease of the heart beat, etc. From above observations it may be assumed that the stimulus conduction of the atria is not one rendered through complete diffusion but through some stimulus conduction pathways running directly from the sinus node to the right and left atria and the Tawara's node.

老年者の心電図に関する研究(第3報) : 老年者異常心電図の予後

A follow-up study was made on 918 aged people during the period of Jan. 1947 to Jan. 1953. The result are as follows : 1) The death rate of those with abnormal electrocardiogram is higher than that of normal electrocardiogram.2) Mortality rate of those with prolongation of the P-Q interval equals that of those with normal electrocardiogram. It can be said, therefore, that prolongation of the P-Q interval is of no significance.3) Mortality rate of those with prolongation of the Q-T interval is 16.2% in the first year and 13.5% in the second year and is higher than that of normal electrocardiogram. Prolongation of the Q-T interval is considered to have some prognostic significance.4) The extrasystole has a similar meaning with prolongation of the Q-T interval in aged persons.5) Mortality rate of those with right bundle branch block equals that of those with normal electrocardiogram or less. Accordingly right B.B.B. has almost no prognostic significance.6) Isolated inversion of the T wave has a great prognostic value. The greater the number of leads with isolated inversion of the T wave, the worse the prognosis becomes. Both Nehb's lead and aV lead seem to have no less a value than standard limb lead. TI II inversion is more important than TII III inversion in determining prognosis, but there is no difference in significance between TI II inversion and TI II III inversion.7) Isolated depression of the RS-T segment is more important than isolated inversion of the T wave. Depression of RS-TI II is more serious than depression of RS-TII III.8) Prognosis of those with abnormal RS-T segment and T wave is not decisively poorer than those with isolated depression of the RS-T segment. So it is clear that abnormal RS-T segment is more important than T wave.9)Mortality rate of auricular fibrillation with abnormal RS-T segment and T wave equals that of abnormal RS-T segment and T wave, so it seems that auricular fibrillation has nothing to do with prognosis.10) Myocardial infarction presents a serious problem, its immediate mortality rate being 26 percent and first year's mortality rate 72 percent. As to the location of the infarction, the highest mortality rate is seen in anteroposterior infarction. There is no difference between anterior myocardial infarction and posterior infarction.11) Summarizing of heretofore discussed prognostic significance of all abnormal electrocardiographic findings, prognostic value is recognized in order of myocardial infarction, the abnormal RS-T segment and T wave, isolated depression of the RS-T segment, isolated inversion of the T wave, prologation of the Q-T interval and extrasystole. Auricular fibrillation, right B.B.B. and prolongation of the P-Q interval have almost nothing to do with prognosis.

単極肢誘導知見補遺(第1報) : 緒論並に湯槽法による単極誘導

In regard to a clinical study of unipolar limb lead, the methods, such as Wilson's, Shimizu-Fujito's, Goldberger's etc. are widely adapted. However, each of these methods can not always be said to be perfect in itself in the sence that the human body is a limited conductor of electricity. Through the immersion experiment at a hot spring bath of Yamanaka National Hospital, I have come to the following conclusion. (1) The electric strom potential of the body laid on its back in water is constant having no relation with its depth of water. It is also constant at any position of the body on its left side in the water deeper than 10 cm and on its right side deeper than 18cm. (2) The electric conductivity of the water in the spring in Yamanaka is 10×10-4ohm-1cm-1 (18°C) and it increases 2×10-4ohm-1cm-1 for every rising of 10°C. This indicates that it corresponds to the salt-solution of 0.071∼0.072% and is 100 times as better as city-water in its conductivity. (3) As for the influence of bathing upon the electrocardiogram, little change is recognized before and after bathing. (4) When in water the different electrode is placed at a neighbouring corner of the left shoulder and the different one to the corner of the tub, or to the opposite corner, the same curved-line is obtained in either cases, that is, the unipolar limb lead is brought about in the immersion experiment. (5) In order to take my unipolar limb lead, it is necessary to lay the body parallel, with water level, although the potential of the upper limb is unchanged with its position and its motion in water. (6) If much attention is paid to keep well the conditions above mentioned, the absolute unipolar lead may be possible.

Studies on the Relationship between the Initial Deflection of Electrocardiogram and the Histologic Fndings following the Experimental Myocardial Infarction (IV).

In experimental myocardial infarction was observed the relationship between the initial deflection of ecg and histologioc findings. 1. Low voltage (under 0.5mV in all leads) was observed in cases, which myocardial damage were in the highst degree. 2. In the other cases, the changes of the initial deflection were variously. In the cases, which had aneurysma at the ventricular apex, the initial complexes deflected downwards, and not upwards in lead II and III. For detailed analysis of initial deflections were calculated the largest potentials (Φ_A) and their directions (θ_R) by means of orthogonal isoscale triangle coordinate (Maekawa). Results were as following. 3. In 5 cases (A-group), which Φ_A increased, was the extension of myocardial damage relatively localized and superficially. Φ_A increased immediately after the operation for the almost cases. The change of θ_R showed undetermined results compare with that before operation. 4. In 9 cases (B-group), which Φ_A decreased, the extension of myocardial damage excelled the apparent width. Histologic change was diffuse and reached to deep and degree of degeneration of myocardium was higher. Φ_A decreased immediately after the operation for the most cases. θ_R deviated to the right. 5. In the 6 cases (C-group), which Φ_A showed no remarkable change, was myocardial damage the same as A & B groups. The change of Φ_A in the cource of experiment and rotation of θ_R were variously in each cases. 6. In all cases, ecg were monophasic or biphasic in the sometime during the experiment. These results of the experiment showed that electrical change of the heart is produced by myocardium itself and its electrical potentials are representated as vectors directed from endcardium to epicardium according to excitement of myocardium. And so, ecg by limb lead represents rotation of a vector, which is resulted from those vectors. These facts give a experimental evidence to the "Chain-doublets" theory (Maekawa), that supposes the causality among the three physical phenomena, namely electricity, contraction and double refraction of myocardium.

Studies on the Relationship between the Initial Deflection of Electrocardiogram and the Histologic Fndings following the Experimental Myocardial Infarction (III).

In experimental myocardial infarction was observed the relationship between the initial deflection of ecg and histologioc findings. 1. Low voltage (under 0.5mV in all leads) was observed in cases, which myocardial damage were in the highst degree. 2. In the other cases, the changes of the initial deflection were variously. In the cases, which had aneurysma at the ventricular apex, the initial complexes deflected downwards, and not upwards in lead II and III. For detailed analysis of initial deflections were calculated the largest potentials (Φ_A) and their directions (θ_R) by means of orthogonal isoscale triangle coordinate (Maekawa). Results were as following. 3. In 5 cases (A-group), which Φ_A increased, was the extension of myocardial damage relatively localized and superficially. Φ_A increased immediately after the operation for the almost cases. The change of θ_R showed undetermined results compare with that before operation. 4. In 9 cases (B-group), which Φ_A decreased, the extension of myocardial damage excelled the apparent width. Histologic change was diffuse and reached to deep and degree of degeneration of myocardium was higher. Φ_A decreased immediately after the operation for the most cases. θ_R deviated to the right. 5. In the 6 cases (C-group), which Φ_A showed no remarkable change, was myocardial damage the same as A & B groups. The change of Φ_A in the cource of experiment and rotation of θ_R were variously in each cases. 6. In all cases, ecg were monophasic or biphasic in the sometime during the experiment. These results of the experiment showed that electrical change of the heart is produced by myocardium itself and its electrical potentials are representated as vectors directed from endcardium to epicardium according to excitement of myocardium. And so, ecg by limb lead represents rotation of a vector, which is resulted from those vectors. These facts give a experimental evidence to the "Chain-doublets" theory (Maekawa), that supposes the causality among the three physical phenomena, namely electricity, contraction and double refraction of myocardium.

Standardizing factors in electrocardiography.

Modifications in recorder standardization are required to correct inherent scalar differences among potential differences measured in a given electrocardiographic reference frame. In the frontal plane, agreement between the resultant vectors calculated from unipolar limb lead measurements and from standard lead measurements can be obtained by standardizing the galvanometer for recording the unipolar limb lead potentials at √3 cm. per millivolt. A method for calculating this "standardizing factor" and similar factors for other reference frames is presented and applied to calculations for the equilateral tetrahedron, the isosceles tetrahedron, and the cube.

Electrocardiographic Changes in Pulmonary Collapse: Artificial and Spontaneous Left-Sided Pneumothorax Studied by Conventional and Unipolar Methods

Conventional and unipolar limb leads, and CF and unipolar chest lead electrocardiograms, and chest films were taken in four patients with spontaneous left-sided pneumothorax, and in two tuberculous patients in whom therapeutic pneumothorax was planned. In the first group the studies were made during pneumothorax and following the re-expansion of the lung. In the latter group the studies were made before and after institution of pneumothorax. The characteristic electrocardiographic pattern for Leads I, II, III, and the CF precordial leads was repeated in all six cases. This pattern consisted of a small T1, a T3 larger than T1, QRS small and inverted (or a QS complex), and low or inverted T waves in the chest leads, the chest lead changes being maximal in the more lateral precordial positions. This previously described pattern can be explained on the basis of the “unipolar” lead findings. The standard limb lead changes are apparently produced by the heart assuming an extremely vertical position in the presence of left pneumothorax. The CP lead abnormalities in the recumbent position are related chiefly to the decreased voltage of the precordial V leads, resulting from the interposition of a non-conductor (air) between the heart and the chest wall. The use of the CP precordial leads in the presence of left-sided pneumothorax might lead to a false electrocardiographic impression of coronary artery disease, or even of old myocardial infarction. In the same situation the V leads (Wilson terminal) show a tracing with a low amplitude but with a more normal contour. This would minimize the likelihood of erroneous interpretation.

III. Correlation of electrocardiographic and pathologic findings in anteroposterior infarction

III. Correlation of electrocardiographic and pathologic findings in anteroposterior infarction