Showing papers on "QRS complex published in 1970"
TL;DR: Clinical and necropsy findings in 15 patients with cardiac dysfunction secondary to cardiac amyloidosis are described, and the most reliable anatomic indicator was a firm, rubbery noncompliant myocardium on gross examination.
Abstract: Clinical and necropsy findings in 15 patients with cardiac dysfunction secondary to cardiac amyloidosis are described. The most reliable anatomic indicator of clinically significant cardiac amyloidosis was a firm, rubbery noncompliant myocardium on gross examination. Twelve of 15 patients had congestive cardiac failure that was not alleviated by digitalis therapy, and 8 patients had documented arrhythmias while receiving this drug. Amyloidosis appears to be a cause of congestive cardiac failure in which digitalis is contraindicated. Electrocardiograms in 14 patients showed low voltage of the QRS complex in 13, axis deviation in 10, conduction disturbances in 9, patterns similar to old myocardial infarction in 9 and arrhythmias in 6 patients. In 6 patients the intramural coronary arteries were narrowed by amyloid without significant coronary atherosclerosis: 3 of the 6 had angina pectoris, and 1 of the 3 a recent myocardial infarct. The diagnosis of clinically significant cardiac amyloidosis should be questioned in the absence of congestive cardiac failure and low voltage in the electrocardiogram.
209 citations
TL;DR: The data support the clinical observations that Mobitz II A-V blocks are associated with bilateral bundle-branch block as well as with BH lesions and demonstration of the Wenckebach cycles within the HPS (BH or either bundle branch), which cannot be determined from the surface ECG, has important clinical implications.
Abstract: Fourteen patients with conduction defects were analyzed by using bundle of His (BH) recordings. The BH electrograms were validated by BH and right atrial pacing (AP). In 12 patients with Mobitz type II A-V block, failure in impulse transmission for the dropped beats was localized distal to the recording site of the BH. Three of these 12 patients showed normal QRS complexes. In two of these three, the QRS complexes remained unchanged during intermittent periods of complete heart block (CHB), and thus represent His bundle rhythm with subsidiary pacemaker arising above the bifurcation of the BH. The A-H time in this group of 12 patients ranged from 60 to 160 msec and the H-V time ranged from 40 to 90 msec. At any atrial rate (NSR or AP) conduction time through the A-V node (A-H), and His-Purkinje system (H-V) remained constant. With increasing atrial (A) rates during AP, the number of impulses blocked distal to the BH increased. At high AP rates Wenckebach phenomenon between A and BH occurred concomitantly w...
206 citations
TL;DR: In patients with first degree heart block during sinus rhythm the A-H time was prolonged and the H-V time was either normal or prolonged, and in higher degrees of heart block, the block was localized either in the proximal or distal A-V junction.
Abstract: His bundle electrograms were recorded in 20 patients. Conduction times from atrium to His bundle (A-H time) and His bundle to ventricle (H-V time) were measured and the sites of delay or block were localized to the proximal or distal A-V junction. On progressively increasing the atrial rate by atrial pacing, the A-H time lengthened, while the H-V time remained constant. Premature atrial beats usually resulted in prolongation of the A-H time only. In some instances, premature atrial beats also resulted in prolongation of the H-V time and aberrant ventricular conduction (change in configuration of the QRS complex). In patients with first degree heart block during sinus rhythm the A-H time was prolonged and the H-V time was either normal or prolonged. In higher degrees of heart block, the block was localized either in the proximal or distal A-V junction.
160 citations
TL;DR: Bundle of His pacing was used to establish a His bundle rhythm in a patient with complete heart block localized within the His bundle, and the retrograde Wenckebach phenomenon was demonstrated.
Abstract: His bundle electrograms were recorded and A-V junction pacing was achieved in 30 patients by a pervenous electrode catheter technic. His bundle pacing was achieved in 26, and A-V node pacing in five patients. Conduction time from atrium to the His bundle (A-H time) and His bundle to ventricular activation (H-V time) were measured. During His bundle pacing, the pacing impulse to ventricular activation time (PI-R) was the same as the H-V time during normal sinus rhythm and remained constant at different pacing rates. With A-V node pacing, the PI-R interval was shorter than the conduction time from atrium to the ventricle (sum of the A-H and the H-V time) but longer than the H-V time, and there was progressive lengthening of PI-R interval, with increase in pacing rates. The QRS complex remained unchanged in all ECG leads with BH and A-V node pacing from that during normal sinus rhythm. During BH pacing, the retrograde Wenckebach phenomenon was demonstrated. Bundle of His pacing was used to establish a His bundle rhythm in a patient with complete heart block localized within the His bundle. BH pacing is of value for validation of His bundle electrograms and differentiation from that of right bundle branch. Clinically, this technic has proved extremely useful in definitive diagnosis of bilateral bundle-branch block in patients with right bundle-branch block and left axis deviation and infarction.
143 citations
TL;DR: Electrophysiologic observations coupled with previous clinical, anatomic, and pathologic findings suggest that the heart block in DMI is usually due to an ischemic lesion of the A-V node, whileheart block in AMI is due to necrosis involving both bundle branches.
Abstract: Bundle of His electrograms were recorded in eight patients with acute myocardial infarction and heart block. Three patients with diaphragmatic myocardial infarction (DMI) and one with subendocardial infarction were characterized by slowing or block above the bundle of His and A-V junctional escape rhythms during periods of advanced or complete block. An additional patient with DMI had block in the His bundle itself. Intraventricular conduction in the above patients was characterized by normal H-Q intervals (35 to 60 msec) and absence of widened QRS. In contrast, three patients with anterior infarction (AMI) manifested complete block below the bundle of His and idioventricular escape. P-H intervals were normal (80 to 140 msec) and A-V conduction was considered unaffected. Our electrophysiologic observations coupled with previous clinical, anatomic, and pathologic findings suggest that the heart block in DMI is usually due to an ischemic lesion of the A-V node, while heart block in AMI is due to necrosis in...
139 citations
TL;DR: Bilateral bundle-branch block was probably the mechanism of block in the majority of the patients with CHB; this emphasizes the clinical significance of ECG patterns indicating bilateral bundle- Branch block during normal sinus rhythm with 1:1 A-V conduction.
Abstract: Twenty-one patients with complete heart block (CHB) were studied by recording His bundle (BH) electrograms. The site of block was localized proximal or distal to the site at which the BH electrogram was recorded. Eighteen patients had block distal to the recorded BH deflection. One of these 18 patients had a narrow QRS complex indicating block within the His bundle; the other 17 had wide QRS complexes probably due to bilateral bundle-branch block. The three patients with block proximal to the His bundle are examples of A-V nodal block or block in the uppermost portion of the BH. Two of these three had normal QRS complexes; the third with a left bundle-branch block pattern demonstrated that during CHB the ECG criteria for the localization of the site of block are not dependable. The conduction time from the atrium to the BH (A-H time) was measured in the 18 patients with CHB distal to the BH and was within the normal range. With atrial pacing there was progressive lengthening of the A-H time, and Wenckebac...
118 citations
TL;DR: The mechanisms of reciprocating tachycardias were studied in three patients with WPW syndrome using the catheter technic of His bundle recordings, finding that short-lived paroxysms of atrial fibrillation in cases 1 and 2 were most probably related to atrial vulnerability.
Abstract: The mechanisms of reciprocating tachycardias were studied in three patients with WPW syndrome using the catheter technic of His bundle recordings. In the first case it could not be determined with certainty whether the tachycardias involved two anatomically independent fascicles or a single longitudinally dissociated pathway. They were terminated by carotid sinus pressure, which caused A-V nodal block, or by properly timed atrial stimuli, which interrupted the circuit. Short-lived paroxysms of atrial fibrillation in cases 1 and 2 were most probably related to atrial vulnerability. In case 3 there were three types of QRS complexes in lead II representing (a) exclusive His bundle conduction, (b) simultaneous His and Kent bundle conduction, and (c) coexisting His and infra-nodal preferential (Mahaim fiber[?]) conduction. This patient also had three types of reciprocating tachycardias-two of ventricular, and one of atrial origin. The reciprocating circuit probably involved the three pathways.
108 citations
TL;DR: Lidocaine in therapeutic doses had a minimal effect on atrioventricular and intraventricular conduction, in contrast to quinidine and procainamide, which may prolong atriaventricularand intravent cardiac conduction.
Abstract: Atrioventricular and intraventricular conduction were studied in 10 patients with arrhythmias before and after rapid administration of lidocaine (1 to 2 mg/kg by direct intravenous injection). Standard electrocardiographic lead II and catheter recordings of His bundle electrograms (H) were obtained. Recordings were made at varied heart rates, utilizing atrial pacing. P wave to H (P-H) interval was used as a measure of atrioventricular conduction. H to onset of the Q wave (H-Q), and H to the terminal deflection of the QRS complex (H-S) were used as measures of intraventricular conduction. After administration of lidocaine, P-H intervals were essentially unchanged in 4 patients, slightly decreased in 4 and slightly increased in 2 patients. H-Q intervals remained constant in all patients and at all rates both before and after lidocaine. H-S intervals were unchanged in 6 patients and increased in 4 patients by 8 to 18 msec (4 to 18 percent of total H-S interval). Thus, lidocaine in therapeutic doses had a minimal effect on atrioventricular and intraventricular conduction. This is in contrast to quinidine and procainamide, which may prolong atrioventricular and intraventricular conduction.
103 citations
TL;DR: The use of transvenous pacemakers in this condition, although widely accepted as an adjunct to treatment of all forms of complete heart block due to myocardial infarction, may reduce mortality in only a small group of patients.
Abstract: Complete heart block, a serious, early complication of acute myocardial infarction, occurred in 9.1 percent of 308 patients with acute myocardial infarction. Patients with anterior infarction have a poor prognosis (80 percent mortality rate) and a widened QRS complex, probably due to involvement of both bundle branches. In inferior wall infarction a narrow QRS complex is associated with the heart block, and the mortality rate is 45 percent. The high mortality rate appears to be due to the extent of the infarction and not to the heart block itself. The use of transvenous pacemakers in this condition, although widely accepted as an adjunct to treatment of all forms of complete heart block due to myocardial infarction, may reduce mortality in only a small group of patients.
80 citations
TL;DR: The electrocardiographic patterns recorded from seven patients with isorhythmic A-V dissociation fall into two distinct groups, which represents a typical biologic feedback control system and the mechanism producing synchronization in pattern II has not been established conclusively.
Abstract: The electrocardiographic patterns recorded from seven patients with isorhythmic A-V dissociation fall into two distinct groups. In pattern I, the P wave fluctuates cyclically back and forth across the QRS complex. The mechanism responsible for this type of A-V synchronization represents a typical biologic feedback control system. The P-R interval is a determinant of stroke volume, which in turn influences the arterial blood pressure. The blood pressure has an inverse effect on the discharge frequency of the S-A node through the baroreceptor reflex. The S-A nodal frequency then affects the P-R interval, to close the feedback loop. In pattern II, the P wave is in a fairly constant position relative to the QRS complex. It is usually coincident with the QRS complex or appears on the ST segment or first half of the T wave. The mechanism producing synchronization in pattern II type of isorhythmic dissociation has not been established conclusively.
62 citations
TL;DR: Atrial pacing assures unchanging antegrade conduction to the ventricles, which permits beat-to-beat observation of changes in the P-R interval or QRS configuration that might result from surgical manipulation.
Abstract: An electrophysiologic technique has been described to localize the atrioventricular (A-V) conduction system during cardiac surgery. The method utilizes atrial pacing with an electrode plaque to insure a supraventricular rhythm, and an electrode probe to localize the specialized A-V pathways. Atrial pacing assures unchanging antegrade conduction to the ventricles, which permits beat-to-beat observation of changes in the P-R interval or QRS configuration that might result from surgical manipulation. The anatomic course of the His bundle and bundle branches is delineated by observing a typical "His spike" during the P-R interval in the electrogram. While heart block is uncommon following repair of uncomplicated ventricular septal defect, this technique has been a distinct aid in the repair of ostium primum atrial septal defects (four cases) and fourteen other complex congenital anomalies.
TL;DR: Electrocardiographic abnormalities were attributed to the transient ischemic or toxic effect produced by the bolus of dye and could result in different degrees of complete or incomplete block in the divisions of the left branch or in an extensive peripheral block affecting large areas of the subendocardial regions of the heart.
Abstract: Selective coronary arteriography produces characteristic ST-T changes associated with significant axis shifts. In patients with normal control AQRS (mean, +88.6°; sd ± 12.2°) left coronary injections induced an important leftward deviation of the AQRS: mean, +8.2°; sd, ±49.1° (P < 0.001). Right coronary artery opacification changed the AQRS from a control mean of +66.5°; sd, ±17.2° to a mean of 89.3°; sd, ±16.7° (P < 0.001). Left axis shifts after left coronary artery injections were significantly more marked than right axis deviation after right coronary injections. Important increases (beyond 0.02 sec) in ventricular activation time were not observed. These electrocardiographic abnormalities were attributed to the transient ischemic or toxic effect produced by the bolus of dye. This could result in different degrees of complete or incomplete block in the divisions of the left branch or in an extensive peripheral block affecting large areas of the subendocardial regions of the heart.
TL;DR: A study of the pacemaker-induced ventricular complexes can be of help in determining the site of stimulation, and the classical Wolff-Parkinson-White beat was interpreted as a fusion beat, as long as exclusive Kent bundle conduction was not present.
TL;DR: Left intraventricular hemiblock resulting from selective coronary arteriography was studied in 20 patients by continuous and simultaneous recording of 2 standard electrocardiographic leads throughout the injection of contrast material to derive statistical analysis of the tracings.
Abstract: Left intraventricular hemiblock resulting from selective coronary arteriography was studied in 20 patients by continuous and simultaneous recording of 2 standard electrocardiographic leads throughout the injection of contrast material. The statistical analysis of the tracings led to the following conclusions: (1) QRS duration was either unmodified or variously increased, sometimes up to 0.12 second. (2) The mean vector of ventricular activation (ÂQRS) rotated leftward in left anterior hemiblock and rightward in left posterior hemiblock. (3) The magnitude of the mean ventricular activation vector (VQRS) increased; when combined with axis deviation this resulted in a significant modification of the White-Bock index of ventricular hypertrophy. (4) The frontal plane direction of the mean initial 0.02 second QRS vector was not significantly modified. (5) Both mean initial and terminal 0.04 second QRS vectors rotated leftward in left anterior hemiblock and rightward in left posterior hemiblock, so that the average absolute angle included between them (¦ÂVi.04 … ÂVt.04¦) was not significantly increased and remained less than 100 °.
TL;DR: Electrocardiographic measurements computed from 405 patients with pulmonary emphysema showed progression of R x changes, a QRS shift in a superior direction and a rightward shift of the P wave as the best indicators of deteriorating pulmonary function.
Abstract: Orthogonal electrocardiograms (Frank system) were recorded from 405 patients with pulmonary emphysema of moderate and severe degree. The diagnosis was based on clinical and radiologic or pulmonary function studies, or both, according to uniform study protocols. Of 333 electrocardiographic measurements computed from each record, different sets of diagnostic criteria were selected for optimal separation of records of patients with pulmonary emphysema from those of normal subjects, using a variety of statistical techniques. The first set consisted of five scalar and vector measurements which can be easily obtained and which do not require access to computer facilities. With these criteria, 80 percent of the records of patients with pulmonary emphysema could be correctly classified, with a false positive rate of 11 percent. With a second set of 14 more complex measurements intended for computer use, 81 percent of pulmonary emphysema tracings were classified correctly, with a reduction in false positives to 5 percent. With the use of additional criteria, a series of 140 records from patients with right ventricular hypertrophy due to pure mitral stenosis could be differentiated from records of patients with pulmonary emphysema in 80 percent of cases. Reduction of the R wave and the R:S ratio in lead X proved to be the best discriminators between records of normal subjects and those of patients with pulmonary emphysema. Correlations with arterial pCO 2 showed progression of R x changes, a QRS shift in a superior direction and a rightward shift of the P wave as the best indicators of deteriorating pulmonary function. Classification procedures were tested on independent record samples including 1 sample of 22 autopsy cases of pulmonary emphysema. Results were nearly identical. They exceeded those reported in the literature, which may be attributed to the use of more reliable electrocardiographic leads and to application of more efficient multivariate classification procedures.
TL;DR: In the known presence of infarction, certain patterns of incomplete and complete LBBB provided rough clues as to the general site of myocardial lesions and the finding of Q waves inferiorly strongly suggested concomitant MI.
TL;DR: A high frequency, constant sinusoidal current can be passed through the chest by a noninvasive technique and pulsatile changes in the thoracic impedance recorded and it is possible that the impedance changes are related to the flow of blood in venous circuits, and the heart.
TL;DR: An electrocardiogram is presented in which spontaneous conversion of 2:1 block with first degree block and incomplete left bundle branch block resulted in 3:2 block with normal conduction of the QRS complex after the short R-R interval, indicating phase 4 depolarization and supernormal conduction are inseparable concepts.
Abstract: An electrocardiogram is presented in which spontaneous conversion of 2:1 block with first degree block and incomplete left bundle branch block resulted in 3:2 block with normal conduction of the QRS complex after the short R-R interval. Alternation of rate and block with every second beat is a variation of previously described bradycardia-dependent bundle branch block. Phase 4 depolarization and supernormal conduction are inseparable concepts, and both may play a causal role in bradycardia-dependent bundle branch block. Criteria for recognition of this type of block should not disqualify cases in which supernormal conduction may be present, particularly since proximity of the QRS interval to the preceding T wave may not be an adequate test for supernormal conduction in clinical situations. A knowledge of phase 3 and phase 4 events allows one to relate different types of clinical aberrance, from premature aberrance through early beat “normalization,” as in bradycardia-dependent bundle branch block, to normal rate aberrance as in typical bundle branch block and, finally, to escape beat aberrance.
TL;DR: In this article, a third degree heart block was produced in anesthetized dogs by injecting 95% ethanol into the region of the A-V node, where the ventricles were paced artificially at a constant rate near the spontaneous rate of the S-A node.
Abstract: Third degree heart block was produced in anesthetized dogs by injecting 95% ethanol into the region of the A-V node. When the ventricles were paced artificially at a constant rate near the spontaneous rate of the S-A node, then the atria and ventricles became synchronized. During synchronization, the P wave oscillated rhythmically around the QRS. When the P preceded the QRS, the arterial blood pressure increased, whereas when the P wave followed the QRS, the blood pressure fell. Synchronization depended on such rhythmical fluctuations in blood pressure because (1) when the blood pressure changes were severely attenuated, synchronization ceased, and (2) simulation of the blood pressure changes by means of a servo-controlled pump also produced synchronization. A biological control system operates in such a way that (1) the P-R interval affects blood pressure by virtue of changes in the atrial contribution to ventricular filling; (2) the blood pressure has an inverse effect on atrial frequency through the baroreceptor reflex, and perhaps other mechanisms; and (3) changes in atrial frequency alter the P-R interval, to complete the control loop.
TL;DR: The characters of the loops observed in 40 patients, 45 years of age or over, are assumed to be related to a delayed activation of the anterolateral wall of the left ventricle and to correspond to left anterior focal block.
TL;DR: Although causing a diversity of findings, myocardial disease may be sufficiently characteristic to justify clinical diagnosis, the evolution of electrocardiographic changes has important prognostic significance.
TL;DR: Intermittent paired ventricular pacing was performed in five patients, one of them with Wolff-Parkinson-White (WPW) syndrome, and in the patient with WPW syndrome A2 preceded H2 at a given coupling interval, suggesting retrograde atrial pre-excitation through an extra-Hisian pathway.
Abstract: Intermittent paired ventricular pacing was performed in five patients, one of them with Wolff-Parkinson-White (WPW) syndrome. Retrograde activation of the His bundle and of the atria was observed in all patients. Bipolar leads with interelectrode distances of 1 mm seemed to be slightly better than the conventional ones (10 mm apart) for the identification of His (H) deflections buried inside the QRS complexes. Diagnosis of retrograde atrial activation was enhanced by the use of a high bipolar right atrial lead. In cases 1 and 2, V2-A2 and V2-H2 intervals consistently lengthened as the V1-V2 interval was reduced. In two other patients, previously present retrograde P waves disappeared as the V1-V2 interval was reduced. Yet at even shorter intervals, retrograde conduction to the His bundle and to the atria was seen. Ventricular echoes occurred in two cases, and reciprocating tachycardia in one. In these instances the His bundle was engaged in both retrograde and forward conduction. Finally in the patient wi...
TL;DR: Body surface maps were helpful in clarifying misleading and atypical conventional electrocardiograms and the presence of simultaneous multiple maxima could only be accounted for by the existence of multiple wave fronts simultaneously present within the heart.
Abstract: The purpose of this study was to determine if there were consistent differentiating patterns in body surface potential maps in children with normal hearts and in those with ostium primum versus ostium secundum atrial septal defects. A second purpose was to interpret the isopotential surface maps in terms of the position of intracardiac electrical wave fronts.
Body surface activity throughout QRS demonstrated three major intervals: developing, transitional, and declining potentials. Patients with both types of atrial septal defects demonstrated complex distributions (multiple maxima) during the transitional interval which were not encountered in normal subjects. In the primum group, the distribution of positive and negative potentials sequentially changed in an inverted pattern as compared to the pattern in those patients with secundum defects. Furthermore, during the transitional interval the potential distribution was considerably more complex in the primum group. In two additional patients, body surface maps were helpful in clarifying misleading and atypical conventional electrocardiograms.
The presence of simultaneous multiple maxima could only be accounted for by the existence of multiple wave fronts simultaneously present within the heart. In particular the emergence of two widely separated anterior chest maxima in patients with secundum atrial defect indicated the simultaneous presence of prominent left and right ventricular wave fronts. Also, the marked differences in the relative positions of the major body surface maximum and minimum could be accounted for only by considerable differences in the position and extent of intracardiac wave fronts. For example, the target distribution, consisting of an isolated minimum surrounded by multiple maxima and positive potentials over the upper body, in the ostium primum patients, indicated epicardial breakthrough in a wave front positioned in the anterosuperior portion of the heart. In contrast, normal subjects and patients with secundum defect had distributions indicating antero-inferior wave front position at the time of right ventricular epicardial breakthrough.
TL;DR: A computer program for the ECG pattern recognition by a computer utilizes a thresholding principle for locating the QRS complex and employs critical points for determining its configuration, which indicate either change of direction or maximal slope of theECG signal.
TL;DR: It is concluded that this rhythm is a common and relatively benign arrhythmia complicating myocardial infarction, and that it should be distinguished from ventricular tachycardia.
Abstract: The incidence, natural history, prognosis, and electrocardiographic characteristics of idioventricular rhythm complicating acute myocardial infarction are described. It occurred as a transient arrhythmia nearly always within 24 hours of infarction in 61 (8%) of 737 patients, and was characterized by paroxysms of between 6 and 20 beats with widened bizarre QRS complexes at a rate of between 60 and 90 a minute. Most cases showed fusion beats and P waves dissociated from the QRS complexes, and in many cases idioventricular rhythm started during the slow phase of sinus arrhythmia. Though it usually occurred in patients with moderately severe transmural infarcts, the incidence of ventricular fibrillation and subsequent mortality was no greater than in patients with infarcts of equivalent severity who did not have idioventricular rhythm. It is concluded that this rhythm is a common and relatively benign arrhythmia complicating myocardial infarction, and that it should be distinguished from ventricular tachycardia.
TL;DR: A patient with WPW paroxysmal tachycardia was treated with a permanent artificial pacemaker, with the electrodes attached to the left atrium, which produced WPW type A QRS complexes, whereas regular sinus rhythm and right atrial pacing resulted in more normal Q RS complexes.
Abstract: A patient with WPW paroxysmal tachycardia was treated with a permanent artificial pacemaker, with the electrodes attached to the left atrium. The pacemaker is turned off at all times except when the patient activates it by holding a magnet over the implanted power unit. Random atrial pacing at a rate of 108/min has always terminated the tachycardia within 1 min, and usually within 10 sec. Left atrial pacing produced WPW type A QRS complexes, whereas regular sinus rhythm and right atrial pacing resulted in more normal QRS complexes. The distinct difference in the QRS complexes suggests preferential conduction through an abnormal pathway during left atrial pacing.
TL;DR: This study confirms the difficulties concerning the correct interpretation of the significance of loss of anteriorly directed forces in the presence of LVH, but the error rate in diagnosis can be considerably reduced by the use of criteria proposed on the basis of this investigation.
Abstract: Electrocardiograms recorded from patients with uncomplicated left ventricular hypertrophy (LVH) often show loss of initial anteriorly directed QRS forces. An attempt was made to differentiate these records from electrocardiograms showing a similar pattern as a result of anterior myocardial infarction (MI). Orthogonal ECGs (Frank system) obtained from 103 patients with LVH were compared to ECG obtained from 327 patients with MI. The ECG were selected on the basis of absence of Q waves in lead Z which in the conventional ECG corresponds to absence of the R wave in right precordial leads. With two simple scalar measurements, namely R amplitude in lead X ≥ 1.2 mv and the sum of amplitudes of R in leads X and Z ≥ 2.5 mv, 66% of LVH cases were recognized. With these criteria, 88% of the MI records were also correctly classified. The same measurements identified 59% of an independent sample of 66 cases of LVH with no Q in lead Z. By utilizing linear discriminant function analysis, 75% of the cases of LVH, 80% of...
TL;DR: Ultrasound tracings were correlated with the electrocardiogram on an oscilloscope recorded by Polaroid photographs in 4 patients and each had angiographic proof of subclavian steal.
Abstract: Ultrasound tracings were correlated with the electrocardiogram on an oscilloscope recorded by Polaroid photographs in 4 patients. Each had angiographic proof of subclavian steal. Measurements were recorded between the peak of the QRS complex and the foot of the pulse wave upswing. The patients showed a pulse delay of 0.03 to 0.06 second; normal controls a delay of 0.00 to 0.01 second.
TL;DR: Voltage criteria were formed using the magnitude of the maximum QRS vector, while additional QRS criteria were developed using the following characteristics of the transverse plane QRS loop found in LVH: leftward displacement of the initial and terminal deflections; increased magnitude of posteriorly directed vectors.
TL;DR: Elderly patients with right bundle-branch block and left axis deviation were studied vectorcardiographically utilizing the McFee-Parungao system and it is assumed that both vector Cardiographic patterns may result from an abnormal spread of excitation resulting from bilateral branch conduction disturbances.
Abstract: Thirty-four elderly patients with right bundle-branch block and left axis deviation were studied vectorcardiographically utilizing the McFee-Parungao system. Atherosclerosis, arterial hypertension, angina pectoris, cardiac enlargement, and heart failure were common clinical features in this series. Moreover, intermittent advanced degree of atrioventricular block was present in 10 out of the 34 patients. The vectorcardiograms might be readily classified into two basic patterns, types A and B. In type A (19 cases), the frontal plane loop was open-faced. The initial vectors were directed anteriorly, inferiorly, and to the right. The mid-temporal vectors were located in the left postero-superior octant, and the late portion of the loop was inscribed anteriorly to the right with conspicuous conduction delay. Those vectorcardiographic features associate the characteristic patterns of left superior intraventricular block with complete right bundle-branch block. The type B vectorcardiograms (15 cases) demonstrated anterior clockwise loops in the horizontal plane and superior counterclockwise loops in the frontal plane. From a review of the published reports and from personal data, the authors assume that both vectorcardiographic patterns may result from an abnormal spread of excitation resulting from bilateral branch conduction disturbances.