The electrocardiogram in late middle life

Within the limits of our experience we may state:The following findings, some of which we have previously considered of doubtful significance, are not pathological.Diphasic or iso-electric P-waves in Lead I or inverted P-waves in Lead III, if they become upright on deep inspiration; slurring of QRS complexes, especially in Lead III and slight to moderate notching of R with the QRS interval below 0.10 seconds, “transverse heart,” isolated left axis deviation, moderate inversion of T-III (this last finding is very common).On the other hand, the following findings were not present in this series and must therefore be looked upon with suspicion.Indeterminate or inverted P-waves in Leads I or II, inverted P-waves in Lead III, if they do not become upright on deep inspiration. Inversion of T-waves in Leads I or I and II, or iso-electric T-waves in Leads I or II if they do not become upright on deep inspiration. A P-R interval exceeding 0.20 seconds, a QRS interval exceeding 0.10 seconds, or an S-T interval exceeding 0.34 or 0.36 seconds (the upper limit seems slightly uncertain).It is seen that for the proper evaluation of a doubtful finding deep inspiration and sometimes change in position may be necessary in any lead. Such thorough investigation should always be done when the electrocardiographic findings may be the determining factor in the diagnosis.This material does not indicate whether an isolated right axis deviation is definitely a pathological sign or whether the inverted wave in a transverse heart is always an S-wave.There do not seem to be any characteristic “age-changes” in the electrocardiogram.     

Ligation of the coronary arteries in javanese monkeys : I. Introduction,general experimental results,especially the changes in the ventricular electrocardiogram

Reasons are given why monkeys offer many advantages over other animals for experimental heart research, especially for electrocardiographic research, in spite of the fact that the anatomical structure of their coronary system sometimes differs from that of man. This anatomical structure and its relationship to that of man are described in the Javanese monkey Macaca irus. After the normal electrocardiogram and the influence of various incidental factors on it had been studied, coronary vessels were ligated in these monkeys. In seventeen of the animals described, the anterior descending branch of the left artery (L) was tied off and in fourteen the right artery (R). In one monkey the right artery was ligated seven weeks after the anterior descending branch of the left. The electrocardiograms were recorded in the customary Leads I, II, and III, mostly simultaneously. S-T deviations were shown by all monkeys, except two left monkeys which fell immediately into ventricular fibrillation, and two right monkeys which afterward were shown to have exclusively frontal lesions. The S-T deviation appeared within ten minutes, reached its maximum in about one hour, and disappeared in an average time of one month. The S-T deviation must always be observable in at least two leads; its study in only one lead is of but little value. The direction of the S-T deviation (the electrical S-T axis) was determined, according to the principles of the equilateral triangle, by quantitative measurements in at least two leads. This direction proved to point after left ligation preponderatingly to the left, and after right ligation preponderatingly to the right. There was a small mixed sector, in which the S-T axes of left and right monkeys were shown to overlap. During development of the S-T deviation systole is usually not prolonged. Among the secondary changes in the ventricular electrocardiogram there was often observed an after-wave in a direction opposite to that of the preceding S-T deviation. This was accompanied by a prolongation of systole. Changes in the QRS complex are described in thirteen animals. No definite direct relation between those changes and an altered duration of systole could be found. There appeared to be a probable connection between those changes and septum lesions. An electrocardiogram that after ligation had once changed never returned within six months to its original form completely. Two special cases (one of air embolism and one of a spontaneous heart disease) are described, in which in the monkeys concerned the electrocardiogram resembled that after coronary ligation.     

The ECG of constrictive pericarditis--pattern resembling right ventricular hypertrophy.

The ECG changes in 122 cases of constrictive pericarditis have been reviewed. Ninety-five per cent of tracings were typical and showed a normal QRS axis, low voltage, and generalized T wave flattening or inversion. The remaining six tracings showed evidence of right ventricular hypertrophy and half of these showed right axis deviation in addition. In only one could these findings be readily accounted for by the presence of severe fibrotic annular subpulmonic constriction; the remainder are unexplained and it is postulated that cardiac rotation and distrotion is causative since none of the other mechanisms of right axis deviation or right ventricular hypertrophy were operative.     

Electrocardiographic changes in pneumonia

Daily electrocardiograms were taken on forty-five patients with lobar pneumonia, and on seven patients with bronchopneumonia. The T-wave and R-T changes were very similar to those described in acute coronary artery closure, and the P-R, R-T, and T-wave abnormalities similar to those observed in rheumatic fever. The electrocardiogram in these three diseases is therefore not specific.In eighteen patients (35 per cent) there was a definite increase in the auriculo-ventricular conduction time, ranging from 0.20 seconds to 0.24 seconds. The impaired auriculo-ventricular conduction occurred when the temperature was normal and the patient was beginning to convalesce. Atropine sulphate affected the P-R interval only to a slight degree.There were ten patients with inverted T-waves in Leads I or II and sixteen cases in all with either inverted or flat T-waves. These patients had a poor prognosis. The T-wave inversions occurred early in pneumonia when the prostration was marked. They showed a “cove-plane” or “coronary T-wave” contour, but were, however, always shallow and always transitory. No coronary artery involvement was found in the post-mortem examinations.R-T abnormalities occurred in 93 per cent of the patients with lobar pneumonia. They first appeared with a fall of temperature to normal levels. The R-T deviations were similar to those observed in acute coronary artery closure but they never progressed to an inverted T-wave.In only one case of bronchopneumonia were there R-T changes, in marked contrast to the frequency of such changes in the lobar pneumonia cases.A tachycardia was present in thirty-five patients. The more marked the tachycardia, the worse the prognosis.A simple bradycardia was found in twenty-four patients. The rate in these cases was often about 40 per minute, once it was as slow as 36 per minute. Atropine at times released the bradycardia.Large T-waves were present twenty-one times, associated usually with the occurrence of a bradycardia.A sinus arrhythmia was discovered in twenty-two individuals, and occurred in convalescence. It was sometimes present with the bradycardia, but often appeared later. Atropine had no effect on the sinus arrhythmia.Premature beats occurred three times.Auricular fibrillation was observed in two fatal cases.“Alternation” of the QRS group occurred in two patients, one of whom died.Auricular flutter was observed once. This patient survived.Transient P-wave inversions in Lead III were recorded three times, transient T-wave inversions in Lead III alone, eleven times; a change in left axis deviation, three times; changes in the QRS group, four times.The fatal cases showed marked tachycardia, a large number of T-wave inversions (44 per cent), and an absence of auriculo-ventricular conduction impairment, of bradycardia, of sinus arrhythmia, and of large T-waves.It is suggested that T-wave, R-T, and P-R abnormalities are due to varying degrees of myocardial involvement and hence the electrocardiogram may perhaps serve as a guide as to when to permit a patient out of bed and when to consider him cured.     

The relative risk of spontaneous complete atrioventricular block in elderly patients with impaired intra-ventricular conduction.

We reviewed 144 consecutive patients with symptomatic high grade atrioventricular block. Cases due to congenital heart disease, acute myocardial infarction, cardiac surgery or digitalis toxicity were excluded. Of the remaining, we chose 71 patients in whom atrioventricular conduction was observed either intermittently during complete heart block (CHB) or in electrocardiograms taken within two years prior to documentation of CHB. The mean age was 69 years, with the peak incidence in the seventh decade in 43 men and eight decade in 28 women. Bundle branch block (BBB) was present in 76% of patients as follows: 47% had right BBB (20% with normal QRS axis, 20% with left axis deviation and 7% with right axis deviation), 17% had left BBB (11% with normal QRS axis and 6% with left axis deviation) and 12% had either alternating BBB, right BBB with alternating axis deviation or atypical BBB. "Trifascicular block" patterns accounted for 21% of the total group of CHB. We also studied the prevalence of various patterns of BBB in a group of 2000 random hospital patients of comparable age and sex exclusive of those with acute myocardial infarction and heart surgery. The risk of CHB for the various patterns of BBB was calculated relative to normal intraventricular conduction. All patterns of BBB carried a considerably increased relative risk of CHB, (P smaller than .01). The relative risk was highest for RBBB with left axis deviation and lowest for LBBB with normal or left axis deviation. In the men, 74% had QRS patterns of "bifascicular" or "trifascicular" block during atrioventricular conduction. By contrast, 71% women had atrioventricular beats showing either no BBB or right BBB with normal QRS axis. QRS pattern during CHB was unchanged from that during atrioventricular conduction in 52% if cases (rabge 38%-76% with different QRS patterns) suggesting idiojunctional pacemaker. CHB in these cases was thought to be due probably to coexistent disease in the AV node or His bundle. Although the concept of uni-, bi- and trifascicular block patterns has been useful in identifying patients at greater risk of CHB, the predictability of the electrocardiogram has obvious limitations, particularly in women.     

T-wave changes secondary to left anterior hemiblock as shown by study of intermittent and alternating patterns.

T-wave changes in spontaneous intermittent and alternating LAH have been described. Attention has been called to the fact that, with the onset of LAH conduction, the T-wave axis shifts oppositely to that of the QRS, thus widening the QRS-T angle in the frontal plane by about 95 degrees. This has the effect of causing T-waves to become upright in leads II, III and AVF, even in those in whom T-waves were previously inverted. This described dicordance of QRS and T-wave axes is considered as evidence that LAH conduction is in fact a true conduction abnormality. As a corollary, an inverted T-wave in leads II, III or AVF in the presence of LAH is a primary abnormality and may be an indication of inferior wall myocardial ischemia or infarction. T-waves are lowered but not inverted in lead I as a result of LAH conduction and precordial leads are variably but not significantly altered.     

The electrocardiogram in lupus erythematosus disseminatus

Abnormalities of the electrocardiogram in patients with lupus erythematosus disseminatus have been noted by several authors in case reports. These abnormalities have consisted of low voltage, increased P-R interval, increase in left axis deviation, low or inverted T waves and premature beats.This report presents the electrocardiographic findings in eight autopsied cases of lupus erythematosus disseminatus. All abnormalities noted above were found in this group with the exception of premature beats. In addition, change of axis from normal to right axis deviation occurred. There was also a general tendency toward prolongation of the Q-T interval; in two patients Q-T was abnormally prolonged. Low voltage was not as common as reported in other series.Electrocardiographic changes were seen as long as ten months before death. In those patients in whom a series of records was obtained the electrocardiograms became progressively and increasingly abnormal. In three of eight patients in whom there was anatomic abnormality of the heart there was no change in the electrocardiogram. In all of these, however, there was no series of records; only a single electrocardiogram was available for study.     

Electrocardiograms in rheumatic heart disease in children

Analysis of the electrocardiographic findings in ninety-seven cases of rheumatic heart disease revealed the following: (1) 86 per cent of cases: S and Q waves of the cross type present; (2) 33 per cent of cases: lengthened P-R interval; (3) 32 per cent of cases: T₂ and, to a lesser extent, T₁ waves large; (4) 24 per cent of cases: displacement of S-T segment; (5) 6 per cent of cases: diphasic or inverted T₁ or T₂ wave present; (6) four times as many mitral as aortic lesions were found; 10 per cent of cases showed combined lesions; (7) Q and S waves were more sensitive than axis deviation in determining right or left-sided heart strain; (8) the importance of noting Q and S waves is emphasized by the fact that they occur in the cross combinations three times more frequently in children with rheumatic heart disease than in normal children or even in a group of possible or potential rheumatic heart disease cases.     

Vectorcardiographic QRS loop in spontaneous pneumothorax

Vectorcardiographic QRS loops were recorded in twenty-nine patients with primary spontaneous pneumothorax (SP), comprised of eighteen of left SP and eleven of right SP. The configurations of QRS loops in acute to recovery phases were compared. The patients were classified into three groups according to the degree of collapse of the lung (Group A: 25% or less, Group B: 25% to 50%, Group C: 50% or more). The major features of the QRS loop in SP were as follows: Left SP--Leftward QRS force was markedly reduced and the mean QRS axis showed a shift to the inferior and posterior. The greatest changes in the QRS loop appeared in group B. Right SP--The mean QRS axis tended to shift to the posterior and to the right. For clarifying the cause of the changes in the QRS loop, a simulation study was performed with a two-dimensional electrical field model. The results of the simulation study strongly suggested that the alterations of the QRS loop in spontaneous pneumothorax were mainly due to extracardiac reasons.     

Left spontaneous pneumothorax presenting with ST-segment elevations: a case report and review of the literature

Common electrocardiogram (ECG) changes associated with left-sided pneumothorax include right axis deviation, reduced R-wave amplitude in precordial leads, QRS alterations (amplitude changes), and T-wave inversions. Few reports exist of ST-segment elevations or changes suggestive of acute myocardial infarction (AMI), and these involve older patients with tension pneumothorax and previous coronary heart disease. We report on a young man with no significant medical history, presenting with left-sided spontaneous pneumothorax and ECG changes that included ST-segment elevations and T-wave inversions in the precordial leads, reminiscent of AMI. All changes resolved after decompression of the pneumothorax. On the basis of the patient’s presenting symptoms, response to therapy, and our review of the literature, we propose a number of possible mechanisms explaining his electrocardiographic findings.     

Electrocardiographic changes in young patients with spontaneous pneumothorax: A retrospective study

Primary spontaneous pneumothorax (PSP) commonly occurs in adolescents. PSP symptoms can mimic cardiac event. We aimed to examine electrocardiography (ECG) changes that accompanied PSP in relation to side and size of pneumothorax.A retrospectively reviewed 57 adolescents presented with PSP and underwent a cardiac evaluation.Overall, 49 patients (86%) were male, median age of 16 years. Of these, 1 patient had a known mitral valve prolapse. In 56 patients the initial episode of PSP was unilateral (16 left sided and 40 right sided), and 1 was bilateral. The main initial symptom was chest pain or dyspnea and chest pain 66.6% and 33.3% respectively. Small pneumothorax was right and left sided in 1and 8 patients respectively, medium right (n = 8) medium left (n = 22), large right (n = 7) and large left (n = 10). One additional patient had medium bilateral pneumothorax. ECG findings were abnormal in 12 patients (21%) and included ST elevation in 5 patients, inverted T wave in 2 patients, incomplete right bundle branch block in 2 patients, poor R wave progression, left axis deviation and low QRS voltage in 1 patient each. Only 2 patients had abnormal echocardiography findings, MPV (n = 1) and minimal mitral and tricuspid regurgitation (n = 1). Serum troponin-T levels were normal in all patients.ECG changes were found in 21% among pediatric patients with PSP. No correlation was observed between ECG changes and side/size of pneumothorax. It is important to rule out pneumothorax among children presented with chest pain, dyspnea and ECG changes.     

Changes in the electrocardiogram in status asthmaticus

The aim of this study, based on the electrocardiographic analysis of 42 patients in status asthmaticus, is to define the basic criteria which may be used as a basis for electrocardiographic differential diagnosis. The following ECG changes were observed: the pulmonary "p" wave is common, sometimes with exaggerated amplitude in peripheral leads, however, in the precordial leads, the voltage of the "p" wave is reduced; most cases have a vertical heart with clockwise rotation and mild right axis deviation, S1 Q2 Q3 and the transitional zone displaced to the left. Ten cases also had a S1 S2 S3 appearance and three cases showed Q1 Q2 Q3, simulating myocardial infarction; there is poor progression of the R wave in the precordial leads and marked persistence of the S wave in the left precordial leads. In some cases, a QS complex dominates the right precordial leads. A variation in the amplitude of the QRS with the respiratory rhythm is often seen in V1 and V2; ventricular repolarization shows a lowered J point with an upward oblique ST segment in the peripheral leads. However, in the precordial leads, the repolarization is normal except for three cases which presented a frank hypokalaemia. The mechanism of these electrocardiographic changes appears to depend on the vertical position of the heart caused by over expansion of the lungs and pulmonary arterial hypertension. The elements of the electrocardiographic differential diagnosis with myocardial infarction and pulmonary embolism are discussed.     

气胸心电图特点的临床意义

目的探讨气胸致心电图变化的特点及其临床意义。方法将86例气胸患者分为左侧气胸组59例和右侧气胸组27例，并对比分析两组心电图变化。结果左侧气胸组心电图异常率（84．70％）较右侧气胸组（37．03％）高，差异有显著性意义（x^2=19．9，P〈0．05）。左侧气胸组心电图改变主要表现为胸导联R波递增不足，V3～V6低电压现象。右侧气胸组主要表现为V1、V2QRS电压随呼吸周期呈有规律性变化。结论左、右侧气胸时，各自有其相应的心电图改变，应结合临床和及时作X线胸部检查等及早明确诊断。     

Variations in the deviations of S-T in anterior wall infarction

Reciprocal deviations of S-T in chest leads from right- and left-side positions occur in clinical cases of anterior wall infarction. They conform to changes observed in experimentally produced ischemia of the heart muscle.When myocardial infarction is of anteroseptal location, elevation of S-T in leads from the right side of the precordium may be accompanied by depression of S-T in chest leads from the left side. Then Lead I may also show depression of S-T, and the resulting features may resemble those sometimes seen in the presence of lateral wall infarction.When myocardial infarction is of lateral location, elevation of S-T in leads from the left side of the precordium may be associated with depression of S-T in leads from the right side. However, when infarction fails to include the superficial muscle layers, or when it is located close to the base of the heart, depression instead of elevation of S-T may be present in leads from the left side of the precordium at the customary level.There is great variability in the deviations of S-T in limb and chest leads in clinical cases of myocardial infarction. One determining factor is the site and extension of infarction. Another important factor is that the the chest leads, unlike direct leads used in the experimental animal, record changes of potential from a far greater area than that covered by an electrode placed directly upon the myocardium, that is, from an area which may include damaged and undamaged myocardium. Thus, positive and negative changes of potential may be mixed and the resultant deviation of S-T will depend on whether the positive or negative potential variation prevails. Therefore, reciprocal deviations of S-T in the chest leads are not invariably observed with anteroseptal or lateral wall infarction. Also, in limb leads, in the presence of anterior wall infarction, elevation of S-T may be inconspicuous in Lead I while marked depression of S-T is noted in Leads II and III. On the other hand, in infarction of posterior site, positive and negative changes in S-T potential which originate in damaged and undamaged parts of the posterior wall may neutralize each other. Thus, Lead III may show no deviation of S-T, while marked depression of S-T is present in Lead I.     

Electrocardiographic and radiographic heart changes in women at high altitude

Electrocardiographic, vectorcardiographic and radiographic cardiac changes are described in 8 young women during 10 weeks of residence at high altitude (14,110ft.). The changes in electrical activity were similar in type to those reported in natives of high altitude and also to those in male subjects previously observed at this altitude. Prominent findings at altitude included increased heart rate, a rightward shift in ÂQRS and increased spatial vector magnitude of terminal QRS force (S vector). Minor changes were observed in P wave contour, T wave voltage and contour and in QRS amplitude. A slight reduction in frontal radiographic heart size was also noted; however, lateral views suggested that the over-all size of the heart was probably unchanged during the stay at altitude. Some comments on the probable etiology and significance of the observed changes are given.     

特发性室性心动过速QRS波群电轴与成功消融关系的探讨

为探讨特发性室性心动过速（ＩＶＴ）体表心电图ＱＲＳ波群电轴与射频消融成败的关系，对２３例ＩＶＴ进行射频消融治疗，其中左室ＩＶＴ１５例、右室ＩＶＴ８例。在左室ＩＶＴ中，１０例ＱＲＳ波群电轴左偏（－８１°±９°）者均消融成功；５例电轴右偏者（＋１１０°～＋２３０°）中只有１例（＋１１０°）消融成功。电轴左偏与电轴右偏患者的消融成功率比较（１０／１５ｖｓ１／５），差异有显著性，Ｐ＜０．０５。在右室ＩＶＴ中，５例电轴正常或轻度右偏患者均消融成功；另３例电轴左偏患者均消融失败。结果提示室性心动过速（ＶＴ）时ＱＲＳ波群电轴对术前判断ＶＴ的起源部位及消融难易程度会有所帮助。     

Left axis deviation in healthy infants and children

In a series of 1036 routine electrocardiograms, 14 children, without clinical and echocardiographic evidence of heart disease, showed a left axis deviation in the standard electrocardiogram. Six children also had an incomplete right bundle branch block. Left axis deviation is defined as a mean frontal QRS complex axis being -30 degrees or less. The age varied from three months to 10 years, with a clear predominance of males (13/14). The unusual finding of left QRS axis deviation in normal children is emphasized.     

Common ECG changes in athletes.

The various ECG changes found in a group of 3,000 healthy athletes are discussed on the basis of eight representative ECG recordings. The common findings were sinus bradycardia, atrioventricular conduction disturbances, left and right ventricular hypertrophy according to the accepted voltage criteria, right axis deviation, intraventricular conduction disturbances (mainly in the right side of the heart), and various disturbances of the repolarization phase. The literature on this subject is reviewed, and the possible mechanisms involved in production of the various ECG changes are discussed. It is pointed out that in the absence of other evidence suggestive of cardiovascular disease, these changes should be considered as a normal variant and not lead to restriction of physical activity.     

Left bu;ndle branch block with right axial deviation. Clinic and electro-vectorcardiographic study (author's transl)]

Eleven patients whose ECG and VCG showed a left bundle branch block with right axial deviation (between + 90 degrees and + 150 degrees) were studied with clinical and radiological investigations. All of them had pathological abnormalities of cardiopulmonary apparatus and cardiac enlargement, but only one had congestive heart failure. The right axial deviation was due in one case to the vertical position of the heart in the chest and in three cases to conduction defects of the cardiac impulse through the left bundle branch. In the remaining cases the right axial deviation was dubious. The authors present and discuss all possible factors which could cause such deviation of QRS axis in the left bundle branch block.