Marked Left Axis Deviation Research Articles

Right precordial qrS pattern due to left anterior hemiblock

Five patients with left anterior hemiblock and a qrS pattern in V 2 were studied. In each instance, the q wave disappeared when V 2 was recorded in the fifth interspace and was accentuated when recorded in the third interspace. None of the patients had a history of myocardial infarction or were suspected of having arteriosclerotic heart disease. It is suggested that in the presence of marked left axis deviation, q waves in V 2 or V 1 and V 2 may not be due to myocardial infarction.

Relationship of right bundle-branch block and marked left axis deviation (with left parietal or peri-infarction block) to complete heart block and syncope.

The pattern of complete right bundle-branch block (RBBB) combined with abnormal left axis deviation is shown to be the predominant conduction abnormality during orthograde (antegrade) conduction in patients who have experienced transient or permanent complete heart block (59% of a series of 44 patients). Sequential records on the same patient are presented showing progressive development of the complete pattern from left parietal and peri-infarction block alone and also from RBBB with normal axis deviation. Underlying abnormality is a partial bilateral bundle-branch block, that is, complete RBBB and involvement of the anterior-superior subdivision of the left bundle. The incidence of this pattern in 5,500 consecutive hospital records was 1%. Of these, 10% manifested complete heart block. It is suggested that a history of syncope or dizziness in a patient with the above pattern may denote that episodes of transient heart block have occurred.

Prognostic significance of anterolateral peri-infarction block in surgery for aortic regurgitation ∗

Eighty-four patients underwent open heart surgery with ball-valve (Starr-Edwards or Magovern) replacement for pure or predominant aortic regurgitation. Of the 58 having normal axis deviation, 40 survived; all 5 having left axis deviation alone survived; of the 20 having marked left axis deviation plus anterolateral peri-infarction block, 1 survived; neither of the two having marked right axis deviation survived. No difference between patients with normal axis or left axis deviation with or without peri-infarction block was found by gross pathologic or histologic study, review of physiologic data, review of degree of coronary atherosclerosis, degree of left ventricular fibrosis, or other parameters of investigation. Five patients with aortic regurgitation had abnormal glucose tolerance tests; 3 of these had left axis deviation. It is suggested that anterolateral peri-infarction block accompanying aortic regurgitation indicates an abnormality of the myocardium which may be expressed as failure to defibrillate, poor myocardial contraction and increased irritability. Because of the absence of infarction or histologic evidence of specific abnormality, the term, anterolateral myopathic block might be more appropriate than anterolateral peri-infarction block in the individual with aortic regurgitation. The presence of this electrocardiographic abnormality in a patient with aortic regurgitation indicates an increased risk of cardiopulmonary bypass and aortic valve replacement.

Significance of marked left axis deviation: Electrocardiographic-pathologic correlative study

Significance of marked left axis deviation: Electrocardiographic-pathologic correlative study

The Significance of the Posteriorly Oriented QRS sE Loop in Congenital Heart Disease: A Potential Source of Error in the Electrocardiographic Diagnosis of Ventricular Hypertrophy

In 15 necropsy-proved cases with various congenital cardiac malformations, potential sources of error were present when utilizing conventional electrocardiographic criteria to determine ventricular hypertrophy. These potential sources of error were the ultimate result of three types of posteriorly oriented QRS sE loops, with the culminative electrical forces in all cases resulting in rS complexes in lead V 1 and deep S complexes in lead V 6 . Type I QRS sE loops were oriented right and posterior. Each case at necropsy showed isolated right ventricular hypertrophy. The proper electrocardiographic interpretation of right ventricular hypertrophy is aided by a predominant R wave in lead V 4 R and marked right axis deviation in the frontal plane, even though an rS or QS wave is present in lead V 1 . Type II QRS sE loops were positioned directly posterior, with little rightward or leftward projection, producing sterotype rS complexes in all precordial leads, including lead V 4 R. This type of QRS loop is present in malformations with distortions of their conduction system. Type III QRS sE loops, positioned posterior, leftward , and superior, also have rS complexes in V 1 . By conventional electrocardiographic criteria each case had left ventricular hypertrophy, confirmed in all at necropsy. In addition, however, relatively deep S waves and tall R waves were present in V 6 and aVR, respectively. These patterns might suggest additional right ventricular hypertrophy—a supposition unconfirmed at necropsy. Thus we interpret these patterns as a manifestation of marked left ventricular hypertrophy, even though the terminal portion of the QRS sE loop is rightward and posterior. The association of marked left axis deviation and a decrease in the size of the S wave in lead V 7 aids in the proper diagnosis of isolated left ventricular hypertrophy.

Marked left axis deviation: Parietal and peri-infarction block ∗

Marked left axis deviation: Parietal and peri-infarction block ∗

Arrhythmias in Acute Myocardial Infarction

SUMMARY Five hundred admissions for acute myocardial infarction were studied for the incidence of arrhythmias. (The incidence of death in the entire series was 24 per cent). Three hundred and eighty-one patients representing 400 admissions demonstrated an arrhythmia of some type (80 per cent). In those with any arrhythmia, death occurred in 27 per cent; in those without arrhythmia, death occurred in 12 per cent. Serious arrhythmias, however, were accompanied by a death incidence of 47 per cent. The incidence of serious arrhythmias remained relatively constant among all age groups, while the incidence of lesser arrhythmias increased with age. With increasing age, there was a greater incidence of death in those with serious arrhythmias, despite the fact that the incidence of serious arrhythmias remained relatively constant at various ages. Among men with serious arrhythmias there was a 10 per cent higher incidence of death than among women of the same age. The incidence of death in patients having minor arrhythmias or normal rhythm was lower than that for the entire series but increased from 8 to 22 per cent with advancing age. Sex did not alter the incidence of death in this group. Ventricular tachycardia was associated with the highest incidence of death (61 per cent). Sinus bradycardia was associated with a lower incidence of death (11 per cent) than was encountered in the overall series (24 per cent). In sinus tachycardia, the incidence of death (50 per cent) was twice that for the entire series. Among the various anatomic types of infarction, lateral and multiple infarcts were associated with a higher than average incidence of death (68 per cent). Although there was no increased incidence of serious arrhythmias, the incidence of death was greater when serious arrhythmias occurred in these types of infarcts. As compared to the same arrhythmias in association with other anatomic types of infarction this may have resulted from the older age of patients having these infarcts or from the frequent association of these infarcts with altered blood flow to the S-A or A-V node. Hypertension, marked left axis deviation, diabetes mellitus, shocks, and certain other factors did not seem to influence the incidence of death in patients with the various arrhythmias. The treatment of each arrhythmia is briefly discussed, as are the indications and contraindications for the commonly used cardiac drugs.

The clinical significance of uncomplicated marked left axis deviation in men without known disease

T HE electrocardiographic finding of marked left axis deviation occurs in a wide variety of clinical conditions.l+? These include acquired diseases which alter myocardial integrity, such as myocardial fibrosis, myocardial infarction, myocardiopathies and left ventricular hypertrophy. In addition. either congenital or acquired interruption of the conduction system may be associated with left axis deviation. Alteration of electric resistance of pulmonarytissue,resulting from chronic pulmonary disease,’ is yet another cause. Left axis deviation also occurs in individuals without clinically apparent cardiac disease. There are those who believe that, in this latter circumstance, left axis deviation is an indication of an “aging heart”; others consider it merely an indication of an altered “electrical position.” Still other observers regard left axis deviation (if it is the only finding in an apparently healthy subject) as a variant of the normal. Thus, a question requiring an answer is, ” W/tat is the clinical signz&ance of left axis deviation in the apparently flealthy individual?” Although retrospective studies have been reported,3r4 no prospective study, to our knowledge, has been made to demonstrate the incidence of cardiovascular disease in apparently healthy individuals who exhibit left axis deviation. Thus, in undertaking this study, it was our intention to determine the clinical significance of left axis deviation in apparently healthy subjects.

QS and QR pattern in leads V<SUB>3</SUB> and V<SUB>4</SUB> : Electrocardiographic and Pathologic Correlation on 41 Cases, Including 25 Cases without Myocardial Infarction

Although a QS or QR pattern in leads V3 and V4 is generally accepted as a diagnostic sign of myocardial infarction, similar patterns are also found in cases without infarction. Among 41 autopsied cases with significant Q waves in leads V3 and V4 there were 25 not associated with myocardial infarction. These electrocardiographic abnormalities were rather frequently observed at terminal stage and also in cases with severe pulmonary emphysema. It is difficult to decide whether myocardial infarction is present when significant Q waves persist without any other definite signs and symptoms, although the presence of coronary T wave in a precordial lead and/or marked left axis deviation is suggestive of infarction. The cause of significant Q waves in the absence of myocardial infarction was discussed and altered position of the heart was suggested to be responsible.

Marked left axis deviation indication of cardiac abnormality

The electrocardiograms of 154 patients with left axis deviation of the QRS of between −30 and −90 degrees (LAD) were correlated with the findings clinically and at necropsy. Only 4 patients (2.6 per cent) did not have cardiac abnormality, even though in 17 patients the electrocardiograms were normal except for the left axis deviation (LAD). Myocardial infarction was present in 52 per cent of the patients, and unequivocal coronary artery disease in an additional 13 per cent. The angle between the mean initial 0.04-second and mean terminal QRS vectors was of little value in predicting the presence of myocardial infarction. Emphysema was thought to have only a contributory role in producing LAD. The data on 100 consecutive living patients with LAD and on 100 consecutive living patients under 40 years of age were interpreted as affording additional support to the conclusion that LAD, with rare exception, is electrocardiographic evidence of cardiac abnormality.

A case of tetralogy of Fallot with a patent foramenovale (pentalogy) showing a marked left ventricular hypertrophy and left axis deviation

Summary The clinical and pathologic findings in a case of tetralogy of Fallot associated with patent foramen ovale are presented. It is believed that this is the first reported case of a tetralogy of Fallot with a hypertrophy of the left ventricle and a left axis deviation substantiated by autopsy.

Acute coronary insufficiency due to pulmonary embolism

A study of forty-one consecutive fatal cases of pulmonary embolism confirmed by autopsy showed that acute coronary insufficiency is an important factor in determining the electrocardiographic and myocardial effects following embolism of the pulmonary artery. The electrocardiographic pattern of “acute cor pulmonale” (deep S 1 and Q 3, depressed RS-T in Lead I, elevated RS-T in Lead III and T 3 inversion) occurred in only a minority of cases. In the majority the electrocardiographic changes were those characteristic of acute coronary insufficiency, namely, RS-T depression and T wave inversion in one or more leads and often in all leads. Antecedent hypertensive or arteriosclerotic heart disease and cardiac hypertrophy were important predisposing factors of acute coronary insufficiency. The classical cor pulmonale pattern was seen more often in patients with previously normal hearts. When the electrocardiogram prior to the embolism was very abnormal, the electrocardiographic changes were usually those of coronary insufficiency or, less often, atypical in character. Furthermore, the presence of marked left axis deviation made the development of the cor pulmonale pattern less likely. Right ventricular dilatation was not regularly associated with either “cor pulmonale” or “coronary insufficiency” electrocardiogram. The pattern of coronary insufficiency was often noted in patients with marked dilatation of the chambers of the right side of the heart, a fact which suggests that coronary insufficiency and right ventricular strain may occur simultaneously following massive embolism of the pulmonary artery. Changes indicative of myocardial necrosis or infarction resulting from acute coronary insufficiency were found in ten cases or 24 per cent. In three of these cases there were gross changes in the myocardium and in seven cases histologic changes. Acute occlusion of a coronary artery was not seen in any of the hearts. The most frequent sites of necrosis were the subendocardial layer of the left ventricle and the papillary muscles. The anterior and posterior walls of the left ventricle were involved with equal frequency. The right ventricle was involved in only one case, emphasizing the greater deleterious effect of pulmonary embolism on the left ventricle. Acute myocardial changes were found in cases with electrocardiograms indicative of cor pulmonale as frequently as in cases with electrocardiographic signs of acute coronary insufficiency. Coronary insufficiency following embolism of the pulmonary artery is caused by diminished coronary blood flow and myocardial anoxia which result from systemic shock, right ventricular dilatation, anoxemia and possible reflex vasoconstriction. The pathologic physiology and relative importance of these factors are discussed.

The significance of marked left axis deviation of the electrocardiogram: Faulkner, J. M., and Duncan, C. N.: Am. J. M. Sc. 208: 205, 1944

The significance of marked left axis deviation of the electrocardiogram: Faulkner, J. M., and Duncan, C. N.: Am. J. M. Sc. 208: 205, 1944

A proved case of dextroposition of the heart, showing left axis deviation in the electrocardiogram

A case of dextroposition of the heart with right ventricular hypertrophy proved post mortem is presented because there was in the electrocardiogram marked left axis deviation. The significance of this finding is discussed.