Showing papers on "QRS complex published in 1972"
TL;DR: The results favor reentry as the causal mechanism for the tachycardias in patients who suffered from recurrent attacks of ventricular tachycardsia.
Abstract: The initiation and termination of tachycardias were studied in five patients who suffered from recurrent attacks of ventricular tachycardia. In four, coronary artery disease with old myocardial infarction was present. A ventricular tachycardia could be initiated in all patients by a single right ventricular premature beat given during regular driving of the right ventricle. The tachycardia could be terminated by a single right ventricular premature beat, or two right ventricular premature beats given in close succession. In four of our patients an early right ventricular premature beat was followed by the next QRS complex of the tachycardia after an interval shorter than compensatory. Our results favor reentry as the causal mechanism for the tachycardias in our patients. Possible pathways for circus reentry leading to ventricular tachycardia can theoretically be composed of (1) the bundle branches, (2) Purkinje fibers with or without adjacent ventricular myocardium, (3) infarcted or fibrotic ventricular tissue, and (4) combinations of (1), (2), and (3).
489 citations
TL;DR: Impulse conduction through the A-V node was normal in all four cases, as could be concluded from the effect of increased atrial driving rate and of accurately timed atrial premature beats.
Abstract: Four patients are described with different degrees of conduction disturbance within the His bundle. In one patient with a Mobitz type II atrioventricular (A-V) block with normal QRS complexes the blocked atrial beats were followed by a His potential. Since the QRS complexes of the conducted beats were completely normal, the site of the block was thought to be in the distal part of the His bundle. In the other three patients with a 2:1 A-V block, a nearly complete A-V block, and a complete A-V block, two distinct His potentials could be discerned, one (H) following each atrial beat, the other (H') preceding each ventricular activation. In the patient with 2:1 A-V block a Wenckebach phenomenon within the His bundle could be produced at certain atrial driving rates. Impulse conduction through the A-V node was normal in all four cases, as could be concluded from the effect of increased atrial driving rate and of accurately timed atrial premature beats. The site of the block could not be predicted from the con...
96 citations
TL;DR: Surgical findings confirmed the existence of a left bundle of Kent, and the division of the His bundle resulted in a maximal W-P-W deformity (type A) and abolished the reciprocating tachycardia.
Abstract: Total atrioventricular bypass (Kent bundle) does not explain all the findings in some cases of Wolff-Parkinson-White (W-P-W) syndrome. Two cases are reported in which two accessory pathways, set in series or in parallel, could be demonstrated. In case 1, a short P-R interval, gap phenomenon, and presence of delta wave with either a short or long P-R interval suggested the hypothesis of an atrio-His accessory path (James fibers). The presence of a type-B delta wave during His stimulation demonstrated the takeoff of another bypass (Mahaim fibers) below or at the point of stimulation. The His-ventricle accessory path had a supernormal phase of conduction during either atrial or His stimulation. In case 2, the rapid spread of the impulse to the His bundle (P-H 65 msec) was responsible for a normal H-R interval (35 msec) during either reciprocating tachycardia or normal sinus rhythm wtih a nonwidened QRS and minimal W-P-W deformity (partial cancellation of the delta wave). During reciprocating tachycardia, alt...
85 citations
TL;DR: It is concluded that the electrocardiographic age trends in asymptomatic populations are to a large extent due to latent coronary artery disease.
Abstract: There are significant electrocardiographic age trends in adult healthy populations from the third to the fifth decade in QRS and T amplitudes (decrease with age) and direction (left axis shift with age) in conventional electrocardiographic leads, which flatten out after age 50. The decrease of amplitudes is more pronounced in men than in women. Age trends of intervals are absent or small. However, the incidence of premature supraventricular and ventricular beats increases with age. Overweight accelerates the age trends. Diagnostic implications are discussed, particularly for recognition of left ventricular hypertrophy. Magnitudes and directions of maximal spatial QRS and T vectors show age trends similar to comparable conventional electrocardiographic items. Initial spatial 20 msec vectors also decrease with age; therefore, “poor progression of the R wave in the anterior chest leads”, often interpreted as compatible with anterior wall myocardial infarction, is a normal age trend. In the majority of studies, the effect of age is more pronounced in populations with high prevalence of coronary artery disease than in populations with low incidence. Coronary artery disease, as long as the resting electrocardiogram is normal, accelerates the age trends. The frequency of ischemic response to exercise is greater, with more pronounced age trends, in populations with high prevalance of coronary artery disease. It is concluded that the electrocardiographic age trends in asymptomatic populations are to a large extent due to latent coronary artery disease.
82 citations
TL;DR: Tachycardias originating in the left bundle branch and documented by right, left, and His bundle recordings have been produced in animals given excessive digitalis, and bidirectional depolarization of the His bundle with fusion His potentials could be demonstrated.
Abstract: Ectopic atrial, A-V junctional, and ventricular tachycardias in man have been associated with digitalis medication. Recently it has become possible to distinguish various locations of pacemakers within the specialized conduction system of the ventricles on the basis of the form of the QRS complexes in the standard electrocardiogram. Tachycardias originating in the left bundle branch and documented by right, left, and His bundle recordings have been produced in animals given excessive digitalis. We have noted a similar tachycardia in a patient with ischemic heart disease receiving digitalis during hypokalemia. The QRS complexes were 0.10 sec in duration and by contour suggested an ectopic focus located in the posterior fascicle of the left bundle; His bundle recordings were consistent with this diagnosis. As the ectopic rhythm became synchronized with a slightly irregular sinus rhythm, bidirectional depolarization of the His bundle with fusion His potentials could be demonstrated.
77 citations
TL;DR: His bundle electrograms were recorded in three patients with heart block who subsequently died, and Serial sections of the conduction system were performed, revealing relatively insignificant A-V nodal lesions and major destructive lesions of both bundle branches.
Abstract: His bundle electrograms were recorded in three patients with heart block who subsequently died. Serial sections of the conduction system were performed. Two patients had complete block distal to H with wide QRS and P-H intervals of 135 and 100 msec, respectively (normal 80-140 msec). Postmortem (PM) revealed relatively insignificant A-V nodal lesions and major destructive lesions of both bundle branches. The third patient had block proximal to H with left bundle-branch block and H-V prolongation. PM revealed amyloidosis of the A-V nodal approaches and fatty infiltration of the A-V node and His bundle. There were also fibroelastic lesions, with total disruption of the left and moderate involvement of the right bundle branch. The first patient also had sinus pauses as well as delay between what was felt to be posterior internodal tract depolarization and the P wave. PM also revealed arteriolosclerosis, mononuclear cell infiltration, and fibroelastosis of the SA nodal approaches. Block distal to H appeared t...
67 citations
TL;DR: It is recommended that selective left ventricular angiocardiography be performed when patients with the Turner phenotype undergo diagnostic cardiac catheterization, especially when the frontal ÂQRS is superiorly directed.
Abstract: This study of individuals with familial and sporadically occurring 46 XX or XY Turner phenotype documented a wide range of right- and left-sided cardiovascular abnormalities and a previously unreported eccentric hypertrophy of the left ventricle. A mother and five of her seven children had abnormal cardiovascular findings. Five had an abnormal electrocardiogram with frontal AQRS of -60° to ±180° and rS or rsr' in V1 and rS, qrS, or qRS in V5. Catheterization demonstrated the following anomalies: coarctation of the aorta in three, valvular aortic stenosis in one, pulmonary valvular insufficiency with atrial septal defect in one, and pulmonary arterial branch stenosis in one child. All six had a similar abnormality of the left ventricle on angiocardiography. During systole and also in diastole the cavity was encroached on in its superolateral and posteroinferior aspects. Septal hypertrophy altered right ventricular contour in two. A similarly abnormal electrocardiogram and left ventricle were found in four...
66 citations
TL;DR: The systolic time intervals do not appear to be useful as a diagnostic or prognostic tool in acute myocardial infarction and a reduction in stroke volume is the most likely explanation for the reduction in LVET and QS2.
Abstract: The phases of systole were measured in 51 patients with acute myocardial infarction and three control groups: (1) a group of 40 patients without heart disease, (2) a group of 23 patients admitted to a coronary care unit for chest pain, who did not have an acute myocardial infarction, and (3) a group of 16 patients with stable angina pectoris and arteriographically proven coronary atherosclerosis. In addition, serial measurements were made in the acute myocardial infarction group. Total electricalmechanical systole (QS2), the preejection period (PEP), and left ventricular ejection time (LVET) were measured in each patient from simultaneous recordings of the ECG, phonocardiogram, and carotid pulse tracing. The systolic and diastolic blood pressures and QRS duration were also measured. Corrections were made for heart rate where appropriate. The average PEP was elevated on the first day of myocardial infarction but was within normal limits thereafter. The LVET and QS2 were significantly shortened until the fo...
65 citations
TL;DR: It is suggested that digitalis-induced unifocal ventricular tachycardia originates below the His bundle from Purkinje tissue supplying the left ventricle and demonstrated that automaticity of canine PF from the left Ventricle is preferentially enhanced by ouabain.
Abstract: Epicardial mapping technics were used to locate the origin of ventricular ectopic beats produced by pacing and by the administration of ouabain and acetylstrophanthidin in pentobarbital-anesthetized open-chest dogs. The sequence of epicardial depolarization was determined with close bipolar reference and roving electrodes. The wave of excitation spread in concentric manner from driven points with the origin having the earliest time. Nonparasystolic unifocal ventricular tachycardia (UVT) was then aroused in nine dogs with ouabain or acetylstrophanthidin. Plunge electrodes were inserted for recording and stimulating of bundle of His and Purkinje fibers. Earliest epicardial ventricular activation of the UVT beats always occurred at or near the apex of the left ventricle. Purkinje fiber (PF) spikes from the region of earliest epicardial depolarization appeared just prior to ventricular activation. Pacing at this point produced QRS configuration almost identical to that during UVT. His bundle pacing normalized...
53 citations
TL;DR: Four cases with transient electrocardiographic features which have been attributed to left posterior hemiblock (LPH) are reported, induced by the exercise test in patients with severe coronary artery disease and chronic posteroinferior damage.
Abstract: Four cases with transient electrocardiographic features which have been attributed to left posterior hemiblock (LPH) are reported. These features were induced by the exercise test in patients with severe coronary artery disease. In all of them the following exercise-induced changes were noted: (1) A shift of the main QRS forces inferiorly and to the right (between +90° and +120°). (2) A definite shift of the initial 0.02 QRS vectors superiorly and to the left, causing a small Q wave to appear in leads II, III, and aVF and/or to disappear from leads I and aVL. (3) A SIQIII pattern. (4) A leftward displacement of the precordial transition zone. (5) An increase of QRS duration in about 0.02 sec. Gradual disappearance of the exercise-induced axis shift was observed in all four cases and these findings were compatible with multiple degrees of "incomplete" LPH. The occurrence of transient LPH patterns was related to the development of acute, transient injury in the posteroinferior wall of the left ventricle in the presence of segmental or widespread coronary artery disease and chronic posteroinferior damage. Before the exercise test, two patients had electrocardiographic patterns suggesting old myocardial infarction and the other two had repolarization changes related to inferior myocardial ischemia according to the angiographic findings.
45 citations
TL;DR: Because of the difficulties in the electrocardiographic recognition of coexisting left anterior hemiblock and inferior myocardial infarction, utilization of the Frank vectorcardiogram appears to be a superior means for diagnosis.
Abstract: Using the Frank lead system, the Vectorcardiographic features of coexisting left anterior hemiblock and inferior wall myocardial infarction were characterized in 25 patients The Vectorcardiographic findings most useful for the diagnosis of coexisting left anterior hemiblock and inferior myocardial infarction are: Frontal plane: (1) clockwise and superior inscription of the 20 to 30 msec QRS vectors, (2) counterclockwise and delayed inscription of the terminal 40 msec QRS vectors, (3) maximal QRS deflection vector located in the left superior quadrant, and (4) major area of the QRS loop above the X axis Sagittal plane: (1) superior inscription of the 20 to 30 msec QRS vectors, (2) deviation of the maximal QRS deflection vector superiorly and posteriorly, (3) delay in inscription of the terminal 40 msec QRS vectors, and (4) figure-of-eight or counterclockwise rotation of the QRS loop Because of the difficulties in the electrocardiographic recognition of coexisting left anterior hemiblock and inferior myocardial infarction, utilization of the Frank vectorcardiogram appears to be a superior means for diagnosis
TL;DR: The effect of isoproterenol administered intravenously within 30 to 90 seconds was studied in 106 patients with abnormal negative T waves, and t wave abnormality was reversed in 96 percent of patients with QRS.
Abstract: The effect of isoproterenol (1 to 9 μg) administered intravenously within 30 to 90 seconds was studied in 106 patients with abnormal negative T waves. T waves remained abnormal in patients with QRS >- 0.10 second and in patients with myocardial infarction or pericarditis. T wave abnormality was reversed in 96 percent of patients with QRS
TL;DR: Evidence for functionally distinct longitudinal fascicles only within the distal portion of the common bundle is provided, and the syncytial character of the terminal fascicular (Purkinje) network may minimize the electrocardiographic evidence for such functional specificity within the commonundle.
Abstract: The alterations in ventricular excitation resulting from production of discrete punctate electrocautery lesions in the canine bundle of His were studied. Electrocardiographic changes were correlated with lesions identified anatomically by microscopic examination of the atrioventricular bundle. Although partial or complete atrioventricular block developed from lesions at several levels of the atrioventricular bundle, changes in the form of the QRS complex appeared only when lesions involved the distal portion of the bundle. Such QRS changes were recorded in 21 of 32 instances when the lesion involved the branching portion of the common bundle but in none of 6 instances when the lesion involved only the nonbranching portion of the common bundle. This study, then, provides evidence for functionally distinct longitudinal fascicles only within the distal portion of the common bundle. The syncytial character of the terminal fascicular (Purkinje) network may minimize the electrocardiographic evidence for such functional specificity within the common bundle.
TL;DR: In none of the patients could SN be abolished by atropine, suggesting absence of an important vagal role, and observations favor an electrophysiologic explanation for the phenomenon of supernormality which is most probably related to the increased voltage of the transmembrane action potential in the period commonly known as the period of negative afterpotentials.
Abstract: This report documents five cases of supernormal (SN) conductivity in the sense of unexpected normalization of the previously existing bundle-branch block (BBB) and three cases of SN excitability in which impulses delivered to the ventricles propagated to the myocardium only during a well-defined interval in the cardiac cycles corresponding to the U waves of the preceding beat. In none of the patients could SN be abolished by atropine, suggesting absence of an important vagal role. In the five patients with SN conductivity there were three examples of right BBB in which spontaneous, as well as electrically induced premature atrial beats, were followed by normal QRS complexes only if they reached the right bundle during its SN phase. In the other two patients with bilateral BBB, strategically placed sinus P waves and electrically induced atrial impulses were conducted to the ventricles with normal P-His and His-Q intervals. Analysis of the electrocardiograms and His bundle electrograms indicated that SN con...
TL;DR: It was concluded that in a postero-inferior infarction, the presence of terminal and slurred R waves with a delayed intrinsicoid deflection in Leads III and aV F , is due predominantly to an associated LPSB rather than to peri-infarction block.
Patent•
13 Jul 1972
TL;DR: In this article, the frequency components of the ECG wave that lie predominantly below the frequency range of the normal QRS complex are sensed, these frequency components being typically in the range of about two Hertz to about eight Hertz.
Abstract: A continuous electrical wave representing the electrical action of a patient''s heart is produced (the ECG wave). Frequency components of the ECG wave that lie predominantly below the frequency range of the normal QRS complex are sensed, these frequency components being typically in the range of about two Hertz to about eight Hertz. These frequency components are integrated upon the occurrence of a QRS complex, and the magnitude of the result is then compared to a reference standard. If the magnitude of the integral exceeds the reference standard an output signal indicative of a cardiac arrhythmia is then produced.
TL;DR: Magnetocardiograms of 6 normal male subjects are presented, taken in a magnetically shielded chamber with a newly developed superconducting magnetometer, and are as clear as the conventional electrocardiogram.
Abstract: Magnetocardiograms of 6 normal male subjects are presented. For each subject magnetocardiograms were taken at about 32 positions on the chest; the positions were the junctions of a 2 by 2 inch grid. The electrocardiograms of each subject are also presented, for comparison. The magnetocardiograms are recordings of that component of the magnetic field vector which is normal to the chest. They were taken in a magnetically shielded chamber with a newly developed superconducting magnetometer, and are as clear as the conventional electrocardiogram. They contain the same general features as the electrocardiogram such as QRS, T, P and U waves, but with different ratios. New information about the heart, unavailable to the electrocardiogram, is believed to be contained in the variation of the magnetocardiogram across the chest. It is not yet known how to extract this information.
TL;DR: The mechanism of aberrancy of atrioventricular (A-V) junctional escape beats was investigated in 8 cases, in 5 of which His bundle electrography was performed with both conducted and escape beats recorded as discussed by the authors.
Abstract: The mechanism of aberrancy of so-called atrioventricular (A-V) Junctional escape beats was investigated in 8 cases, in 5 of which His bundle electrography was performed with both conducted and escape beats recorded. Aberrancy in Junctional beats usually shows features of incomplete or complete right bundle branch block and leftward or rightward shift of the QRS axis in the frontal plane. From the morphologic point of view the aberrancy resembles that seen in conducted beats with the additional feature of bifascicular block. Functional aberrancy based on incomplete recovery of the conduction fibers cannot account for aberrancy in slow Junctional rhythms. Phase 4 depolarization may explain the aberrancy in slow heart rates but cannot readily account for the fusion complexes so frequently seen in these rhythms. His bundle electrography in the present study showed a time relation between His spikes and the onset of the QRS complex which excludes the possibility of antegrade conduction of the aberrant beats along the same pathway used by descending sinus beats as well as true Junctional beats descending through the main His bundle. Specifically, the His spikes were found at or near the onset of the QRS complexes in aberrant escape beats, whereas they were ahead of the QRS complexes by the expected interval of 40 to 50 msec in the conducted beats. This temporal relation favors propagation of escape impulses from their origin bidirectionally, that is, simultaneously toward the ventricular myocardium and retrograde toward the main His bundle. This observation, together with the right bundle branch block and the axis deviation, places the escape focus in 1 of 2 fascicles of the left bundle branch: in the superior division for beats displaying right axis deviation and in the inferior division for beats displaying left axis deviation. With acceptance of a fascicular origin for these beats, a satisfactory explanation becomes readily available for the fusion complexes.
TL;DR: A study of the morphologic features of right ventricular ectopic beats produced by stimulating the endocardium of the right ventricle with a nonpacing catheter tip, and a comparison of these features with the patterns of classic left bundle branch block, afforded the following clues.
Abstract: A study of the morphologic features of right ventricular ectopic beats produced by stimulating the endocardium of the right ventricle with a nonpacing catheter tip, and a comparison of these features with the patterns of classic left bundle branch block, afforded the following clues: (1) a wide (> 0.04 second) r wave in lead V 1 ; (2) a QS or rS complex deeper in lead V 4 than in V 1 ; and (3) right axis deviation in the frontal plane occurring commonly in right ventricular ectopic beats and rarely in left bundle branch block. Artificially paced right ventricular beats shared the first 2 characteristics (wide r wave in lead V 1 and deep QS or rS complex in lead V 4 ) with the ectopic beats produced at catheterizatton but, unlike them, displayed an invariable left axis deviation. Application of these findings to the clinical tracing may be helpful in discriminating between right ventricular ectopic beats and aberration of the left bundle branch block type.
TL;DR: The present study confirms that the patterns are not those ofright ventricular hypertrophy or abnormal right ventricular conduction, and casts serious doubt on the idea that the essential explanation lies in persistence of the electrocardiographic-vector Cardiographic pattern of infancy and early childhood.
TL;DR: This slender monograph is a report of the author's observations in his department of cardiology in Amsterdam on the use of bundle of His recordings and the response to external electrical stimulation of the heart by right atrial and ventricular electrodes to determine whether certain regular tachycardias represent atrial flutter, atrioventricular (AV) junctionalTachycardia, or tachy Cardia related to the preexcitation syndrome.
Abstract: This slender monograph is a report of the author's observations in his department of cardiology in Amsterdam. The author states the suspicion that experiments on open-chested animals with cut cardiac nerves are subject to possible error has been dispelled by the experience with external electrical stimulation of the heart in man. The author presents a classification of tachycardias, summarizes the physical signs helpful in diagnosis, and emphasizes the difficulty in differentiating between supraventricular tachycardias with wide QRS complexes and ventricular tachycardias. The text of this monograph deals mainly with the use of bundle of His recordings and the response to external electrical stimulation of the heart by right atrial and ventricular electrodes to determine whether certain regular tachycardias represent atrial flutter, atrioventricular (AV) junctional tachycardia, or tachycardia related to the preexcitation syndrome. The bundle of His recordings were accomplished by passing two or more electrodes by the Seldinger technique
TL;DR: Six children, aged between 3 and 19 years, with congenital complete heart block without associated cardiac disease were studied by His bundle electrography and were thought to have a lesion proximal to the site where the bundle of His potential was recorded and, therefore, were unlikely to develop symptoms or require treatment.
Abstract: Six children, aged between 3 and 19 years, with congenital complete heart block without associated cardiac disease were studied by His bundle electrography. All were symptomatic with resting ventricular rates over 40 beats/min, and electrocardiograms that showed a normal axis and QRS complex. His bundle to ventricular activation was within the normal range in all and the block was proximal to the bundle of His. Ventricular and atrial pacing did not result in retrograde or antegrade conduction. All the patients were thought to have a lesion proximal to the site where the bundle of His potential was recorded and, therefore, were unlikely to develop symptoms or require treatment.
TL;DR: The clinical and vectorcardiographic features were studied in 12 patients, aged 64 to 85 years, with right bundle branch block and left posterior fascicular block, finding the horizontal QRS loop was predominantly anterior with variable direction of inscription, and was termed type I.
Abstract: The clinical and vectorcardiographic features were studied in 12 patients, aged 64 to 85 years (mean 74 years), with right bundle branch block and left posterior fascicular block. The blocks had been present for 1 to 9 years (mean 2.7 years). Five patients had coronary artery disease of whom 4 had vectorcardiographic criteria of inferior wall infarction. In 5 patients the cause was undetermined (probably Lenegre's disease), and 2 patients had aortic valve sclerosis. Other causes simulating this type of bilateral bundle branch block were excluded. In 7 patients the horizontal QRS loop was predominantly anterior with variable direction of inscription, and was termed type I. In 5 patients the loop was normal in position, predominantly counterclockwise and was termed type II. The frontal QRS loop was clockwise with the maximal or half area vector inferior (mean 102.1 °). Two patients died of causes not related to disturbed atrioventricular conduction; complete heart block developed in none.
TL;DR: Most pulmonary embolism episodes are associated with nonspecifically altered or unchanged electrocardiograms as discussed by the authors, and most of these episodes of pulmonary emblomeration occur in patients who have been treated with heparin as an anti-serotonin agent.
Abstract: Most episodes of pulmonary embolism are associated with nonspecifically altered or unchanged electrocardiograms. QRS and T abnormalities of right ventricular “strain,” like significant circulatory changes, require 50 percent embolic obstruction and greatly increased pulmonary vascular resistance. Primary T wave changes appear to be related to increased right ventricular mural tension exaggerating myocardial oxygen requirements and simultaneously compromising the oxygen delivery system. QRS axis and conduction changes result from acute right ventricular dilatation plus hypoxia of His-Purkinje system components. Diagnostic sensitivity is partly related to time and frequency of monitoring. Bronchoconstriction due to serotonin release after embolic impact may produce P wave changes. Experimental studies indicate the protective effect of heparin (as an anti-serotonin agent). Some clinical and electrocardiographic variability may be related to prior treatment with many common medications which act as anti-serotonin agents.
TL;DR: In this article, the authors reported a patient with Wolff-Parkinson-White syndrome who presented with a tachycardia showing an unusual QRS morphology closely resembling that of a ventricular thymus.
Abstract: This paper reports a patient with Wolff-Parkinson-White syndrome who presented with a tachycardia showing an unusual QRS morphology closely resembling that of a ventricular tachycardia. On reversal to a normal rhythm the electrocardiogram showed changes of a type A preexcitation, with subsequent conversion to a type B pattern. This phenomenon was observed on two separate occasions. Such conversion would suggest the presence of two distinct sites for bypass location resulting in preexcitation, thus lending support to the theory of aberrant atrioventricular conduction via a bundle of Kent or neuromuscular tissue connecting atrium to ventricle. The configuration of the QRS complexes during the tachycardia would appear to be due to a circus movement with antegrade anomalous atrioventricular conduction and retrograde atrial stimulation via the bundle of His, although in this case, due to the presence of two distinct anomalous atrioventricular conduction pathways, both antegrade and retrograde conduction via these two pathways alone cannot be excluded.
TL;DR: The diagnosis of Ebstein's malformation of the tricuspid valve was validated by the anatomic enlargement of the left ventricle in 4 autopsy cases, thereby giving anatomic support to this Vectorcardiographic finding in Ebsteins anomaly.
Abstract: Twenty-one cases of Ebstein's malformation of the tricuspid valve were studied vectorcardiographically; in 6 cases vectorcardiographicanatomic correlations were made. The anomaly is viewed as part of a generalized disturbance in the development of the right and, in some cases, the left ventricle. Autopsy sections obtained from the septum and free wall of the right and left ventricle showed areas in which muscle fibers were replaced by connective tissue. The fibrosis in the medial posterior and superior portions of the ventricular septum (first published anatomic observation) explains the reduction and abnormal direction of the initial QRS forces and the appearance and correlation with the vectorcardiogram (absent or very diminished slurred Q loop or, in the absence of the Q loop, an initial slurred R loop) and the electrocardiographic configuration (QR in leads V1, V2 and, at times, V3) in some cases of Ebstein's anomaly. Fibrotic areas of this kind may produce similar configurations in other types of cardiomyopathy. A clue to the differential diagnosis between right atrial enlargement due to Ebstein's anomaly and that due to other causes is the slurring in the QH loop or in the initial RH loop when the QH loop is absent. The diminished muscle areas or the pouch of the right ventricular free wall, or both, give rise, in the presence of the right bundle branch block, to the abnormal slurring of the SH loop in the patients without type B Wolff-Parkinson-White syndrome. This is the equivalent of the electrocardiographic qR, qrR′ or qRR′ configuration in leads III and aVF. Left ventricular enlargement was diagnosed in almost 50 percent of cases. The diagnosis was validated by the anatomic enlargement of the left ventricle in 4 autopsy cases, thereby giving anatomic support to this Vectorcardiographic finding in Ebstein's anomaly.
TL;DR: His bundle recording suggested a site of block in the His bundle, which was the most likely explanation for the occurrence of longitudinal dissociation in the distal His bundle allowing preferential distribution of the cardiac impulse to one or the other ventricle.
Abstract: A patient is described with complete heart block and a ventricular septal defect, both secondary to a stab wound of the chest. The escape rhythm was characterized by a wide QRS interval with a configuration suggesting right bundle branch block. His bundle (H) recordings revealed “split” H potentials with a P-H1 interval of 100 msec and an H2-V interval of 40 msec. Recording of left bundle branch (LB) potentials showed the left bundle branch spike to occur in the H2-V interval with an H2-LB interval of 15 msec and an LB-V interval of 25 msec. Atrial pacing produced prolongation of P-H1, administration of atropine and isoproterenol produced shortening. Wenckebach periods proximal to H1 were noted at an atrial paced rate of 190/min. During the study, the QRS pattern unexpectedly shifted from right to left bundle branch block, with H2 potentials still preceding each QRS interval. The most likely explanation for this was the occurrence of longitudinal dissociation in the distal His bundle allowing preferential distribution of the cardiac impulse to one or the other ventricle. However, the possibility of varying bundle branch block, or shifting of the pacemaker from the His bundle to the bundle branches could not be absolutely excluded. In summary, His bundle recording suggested a site of block in the His bundle. Observations are made on the nature of “split” H potentials and evidence for the occurrence of longitudinal dissociation in the His bundle is presented.
TL;DR: Left posterior hemiblock should be suspected when the ÂQRS direction is about +120 °, with an S 1 -Q 3 pattern and a QRS interval within normal limits, provided right ventricular hypertrophy or a vertical heart can be excluded, and provided there is some form of left ventricular disease.
Abstract: Two cases of transient left posterior hemiblock associated with acute lateral myocardial infarction are reported. The main electrocardiographic features, diagnostic criteria and problems of differential diagnosis are analyzed. The association of left posterior hemiblock with the lateral infarction causes a difficult diagnostic problem. Left posterior hemiblock should be suspected when the ÂQRS direction is about +120 °, with an S1-Q3 pattern and a QRS interval within normal limits, provided right ventricular hypertrophy or a vertical heart can be excluded, and provided there is some form of left ventricular disease.
TL;DR: The electrocardiograms of 50 patients after isolated aortic valve replacement were examined and intraventricular conduction defects were interpreted as evidence of involvement of the conducting system during removal of the abnormal valve, whereas uneven myocardial blood flow during coronary perfusion was thought to be responsible for the appearance of abnormal Q waves.
Abstract: The electrocardiograms of 50 patients after isolated aortic valve replacement were examined. Two main types of postoperative QRS changes were found. In I3 patients intraventricular conduction defects developed, predominantly in theform ofa left anterior hemiblock as an isolated lesion or combined with other focal blocks. The other prominent finding was the appearance of abnormal Q waves suggesting inferior wall infarction in 8 patients, and anterior wall infarction in one. Intraventricular conduction defects were interpreted as evidence of involvement of the conducting system during removal of the abnormal valve, whereas uneven myocardial blood flow during coronary perfusion was thought to be responsiblefor the appearance of abnormal Q waves. The clinical importance of these findings is discussed.