Sympathetically induced atrial tachycardia. Successful treatment by left stellate ganglion block

An unusual type of atrial tachycardia was observed in a 52-year-old woman. The tachycardia occurred only when the patient kept the left upper limb in the lateral and horizontal position. Propranolol, atropine sulfate, carotid sinus massage and occular compression were not effective in terminating or preventing the arrhythmia. Left stellate ganglion block has stopped the tachycardia for at least two years. The atrial tachycardia in this patient was thought to be caused by mechanical stimulation of the left stellate ganglion resulting in pacemaker shifting, as has been demonstrated in the canine heart.     

Echocardiographic analysis of interatrial septal motion.

Interatrial septal motion was analyzed in 12 normal subjects and 19 patients with right or left atrial overloading using a new method for recording echograms of the mid portion of the interatrial septum through each cardiac cycle. In normal subjects, septal motion was characterized by eight distinct points that were identified and designated on the septal echogram. The septum showed gradual anterior motion (toward the right atrium) in mid and end systole and in early diastole. After reaching the most anterior point, it moved posteriorly (toward the left atrium). During mid diastole it showed very little motion. After the P wave of electrocardiogram it showed slight posterior and then anterior motion.In all eight patients with mitral stenosis, the motion of the interatrial septum was diminished. In all seven patients with mitral regurgitation due to chordal rupture, the septal motion was increased. Systolic fluttering of the septum was observed in four of seven patients. In two patients with Ebstein's anomaly, paradoxical motion of the interatrial septum (posterior motion in systole) was observed. In two patients with primary pulmonary hypertension, septal motion was very much decreased. Interatrial septal motion was thought to result from the interatrial pressure gradient through each cardiac cycle. This method of recording the motion of the interatrial septum seems to be useful for diagnosing right or left atrial overloading and for studying hemodynamic events in both atria.     

Histologic and ultrastructural studies on the myocardium in spontaneously diabetic KK mice: A new animal model of cardiomyopathy

The hearts from spontaneously diabetic KK mice and control mice were examined by light and electron microscopy. Myocardial degeneration, myocardial fibrosis and calcium deposits in the myocardium were extensive in KK mice aged 8 weeks. In myocytes of newborn KK mice, an irregular arrangement of myofibrils and poorly formed Z bands were found. Ultrastructural changes in myocytes of KK mice aged 4 weeks consisted of destruction of mitochondria, degenerated myofibrils and abnormalities of Z bands. However, increased mucopolysaccharides in interstitium and thickened basement membranes of capillaries were not found in KK mice, in contrast to the previous reports of myocardial changes in diabetic C57BL/KsJ mice, alloxan-diabetic dogs and hypertensive-diabetic rats. These observations suggest that the cardiomyopathy found in KK mice is not secondary to diabetes mellitus but is caused by other factors.In conclusion, myocardial ultrastructural abnormalities are present in newborn KK mice. Thus, this animal can be used as a model of cardiomyopathy.     

Electrophysiological and histological abnormalities of the heart in myotonic dystrophy

For frequent complications of cardiac involvement, it is important to recognize exactly myotonic dystrophy from a cardiovascular standpoint. Electrophysiological and histological studies were performed in three patients. Analysis of the site of the conduction disturbances was revealed by His bundle electrography proximal to the His bundle in one patient and distal in two other patients. The histological examination for biopsied myocardium by light and electron microscopy disclosed replacement of large areas by fat and also showed varying degrees of cellular damage. The most striking abnormality of the heart muscles was found in the mitochondria in which a peculiar and granular substance bulged into the outer space. Both the conduction system and the myocardium were involved in our cases. The value of His bundle recordings and endomyocardial biopsy in evaluating cardiac abnormality in the disease were discussed.     

Detection of posterior myocardial infarction by body surface mapping: A comparative study with 12 lead ECG and VCG

To examine the diagnostic ability of body surface mapping in posterior myocardial infarction (PMI), mapping was performed in 11 patients with PMI proven by left ventriculography and T1-201 myocardial perfusion imaging (PMI group) and in 44 normal subjects (N group). Map data was analysed by the following methods: (1) potential departure maps at 10, 20, 30, 40 and 50 msec after the onset of QRS; each map indicates the area of decreased potential out of the normal range at the time. (2) AQRS departure map which indicates the area of decreased time-integral value of QRS out of the normal range. True positive (TP) in the PMI group and false positive (FP) in the N group were calculated for each method, and were compared with those of various criteria for PMI with standard 12-lead electrocardiogram (ECG) and Frank lead vectorcardiogram (VCG). The potential departure maps and the AQRS departure map had high TP (10/11 and 8/11) and low FP (0/44 and 0/44). The diagnostic ability of mapping is considered to be higher than that of ECG and VCG. Mapping, especially the departure map technique, is a sensitive and specific method to detect posterior infarction.     

Ventricular arrhythmia with postural dependency

Ventricular arrhythmias associated with recumbency were noted in a 17-year-old man with mild idiopathic myocarditis. These arrhythmias were refractory to several anti-arrhythmic drugs. Frequent ventricular arrhythmias were reproducibly recorded in the supine position and in a 15 degree tilt from the horizontal, while they were completely abolished in positions tilted more than 30 degrees from the horizontal, at which time sinus rate increased to more than 70 beats/min. The ventricular arrhythmias were suppressed during treadmill exercise and markedly aggravated when the underlying sinus rate was decreased during sleep or lying flat in bed. The arrhythmias were entirely abolished by atropine 1 mg. Furthermore, they were suppressed during atrial pacing at the rates of 80 and 90 bpm. Ventricular tachycardia could not be induced by programmed right ventricular stimulation. The appearance of postural arrhythmias in this patient correlated with relative bradycardia suggesting that they may be related to enhanced vagal nerve activity.     

P-wave changes in obstructive and restrictive lung diseases

To evaluate the P wave changes in the electrocardiogram (ECG) in chronic lung diseases, we examined ECGs from twenty patients with interstitial pulmonary fibrosis (the FLD group) and twenty patients with chronic obstructive lung disease (fifteen with pulmonary emphysema and five with bronchial asthma, the COLD group). In the COLD group, the amplitude of P waves in leads II and III increased and the axis of the P wave shifted rightward. In the FLD group, however, these changes were not observed. Furthermore, the axis of the P wave exceeded +70 degrees in all the patients in the COLD group, and was less than +70 degrees for all the patients in the FLD group. The increased P wave terminal force in lead V1 was found in nine patients (45%) of the FLD group and in ten patients (50%) in the COLD group. We concluded that the rightward shift of the axis of the P wave was a characteristic of obstructive lung disease and that it was mainly caused by the overinflation of the lung. This P wave change was not observed in interstitial pulmonary fibrosis.     

Correlation between the direction of the interventricular septum estimated with transmission computed tomography and the initial QRS vectors

A correlative study was performed to relate the interventricular septal angle (As^o) evaluated by transmission computed tomography to azimuth of initial QRS vectors in 52 patients. Patients were divided into five groups: RV volume overloading (RVO), RV pressure overloading (RSO), LV volume overloading (LVO), LV pressure overloading (LSO), and normal control with no cardiopulmonary disease. For measurement of As^o, the leftward and forward directions were designated as zero and 90 degrees, respectively. The mean value of As° was significantly smaller in RVO (14.4°) and RSO (41.1°) than in normal controls (50.4°) and in LVO (53.2°). The mean value of the azimuth of the initial 12-msec instantaneous QRS vectors (H₁₂^o) was significantly smaller in RVO (80.5°), RSO (81.7°), and LSO (81.3°) than in normal controls (113.8°) and in LVO (113.7°).A significant linear correlation was shown between As^o and H₁₂^o in a combined group consisting of RVO, LVO, and normal controls (r=0.70, p<0.001), and also in another combined group consisting of RSO, LSO, and normal controls (r=0.52, p<0.01). It was concluded that the orientation of the interventricular septum was one of the major determinants of the direction of initial QRS vectors, especially in patients with ventricular volume overload or without cardiopulmonary disease.     

Norepinephrine levels in the coronary sinus in patients with cardiovascular diseases at rest and during isometric handgrip exercise

In order to evaluate cardiac sympathetic nerve activity, plasma norepinephrine levels in the coronary sinus (NE_CS) and in the artery (NE_A) were determined in 24 subjects with cardiovascular diseases and in six with functional murmur. The resting NE_CS was greater than NE_A in 14 subjects with normal left ventricular end-diastolic pressure (LVEDP) (p < 0.01) and/or in 22 with normal cardiac index (p < 0.05), whereas NE_CS was not significantly different from NE_A in the remaining patients with elevated LVEDP and/or with reduced cardiac index. Isometric handgrip exercise increased both NE_CS and NE_A (p < 0.001). When subjects were divided into two groups according to the slope of the ventricular function curve (Δ stroke work index/ΔLVEDP), NE_CS during exercise was greater than NE_A in the group having slopes of 1.0 or more (p < 0.01), but neither values significantly differed in the group with slopes of less than 1.0. In the latter group, cardiac NE overflow rate calculated from the difference between NE_CS and NE_A multiplied by coronary sinus plasma flow, was significantly less than that of the former group before and during handgrip (p < 0.05 and p < 0.01, respectively). These results suggest that cardiac norepinephrine release into the coronary sinus is reduced in patients with impaired cardiac function.     

Theoretical considerations on the electrocardiogram of ventricular hypertrophy.

The electrical effect of ventricular hypertrophy is evaluated with an idealized model. Perfectly symmetrical hypertrophy is expected to enlarge the QRS complex with a certain proportion of the amplitude and duration. If the conduction velocity is unaltered, the QRS area will be increased proportionally to the myocardial mass. 2) Based on the preservation of the ventricular gradient, the secondary T change is expressed as a function of the QRS and G vectors. A theoretically interesting parameter, G/QRS ratio, is defined as a measure of the "ventricular gradient density," which is important for the over-all recovery pattern. This ratio is decreased in ventricular hypertrophy and is closely related to the QRS-T angle. 3) From the viewpoint of the theory, clinical cases with left ventricular hypertrophy are examined. The theory describes the cases with uncompicated hypertension fairly well, although variations from case to case are not small. Underlying assumptions and causes of deviations in actual cases are discussed.     

Prolongation of the QT interval induced by probucol: demonstration of a method for determining QT interval change induced by a drug

Sudden death has occurred in monkeys fed large doses of probucol, a cholesterol-lowering drug, given in combination with an atherogenic diet. These monkeys develop prolonged QT intervals and high serum levels of probucol. We investigated the effect of probucol on QT interval and the incidence of ventricular ectopy during a double-blind placebo-controlled study in 16 patients with less than 600 premature ventricular complexes (PVCs) per day and a corrected QT interval of less than 0.44 second. Seven patients received probucol and nine patients received placebo. Three 24-hour continuous ECG recordings were obtained prior to entry into the study and three additional recordings were obtained after 6 months of drug or placebo therapy. A 15-second ECG tracing was sampled from the continuous ECG recording every 30 minutes and, for the group, 15,000 QT intervals were measured permitting construction of QT versus R-R regression lines for each patient before and during therapy. Comparison of the regression lines revealed that the measured QT interval prolonged 20 +/- 18 msec during the awake state and 24 +/- 20 msec during sleep (mean + standard deviation) at matched heart rates in the seven patients receiving probucol (p less than 0.01). Using Bazett's formula to correct for rate, corrected QT interval prolonged 22 +/- 23 msec in the awake state and 20 +/- 18 msec in the asleep state (p less than 0.01). In probucol treated patients QT interval prolongation was directly related to increasing probucol plasma levels (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Variations in the critical cycle length inducing rate dependent bundle branch block

In five patients with tachycardic RDBBB (rate dependent bundle branch block), variations in the critical CL (cycle length) inducing RDBBB were investigated. In one patient, independent of changes in the preceding CL, the critical CL inducing RDBBB was invariable, extending over two years. In the other patients, the critical CL inducing RDBBB varied within a comparatively short period. However, when RDBBB was maintained for only a few cycles, the critical CL allowing reversion to normal conduction was always longer than the critical CL inducing RDBBB here, in all patients except one. In one patient such a distinct difference in CL could not be disclosed because the critical CL inducing RDBBB varied from cycle to cycle.These observations suggest that independent of variations in the refractory period of the blocked bundle branch, the critical CL allowing reversion to normal conduction was considerably longer than this refractory period in all patients. The possible mechanisms by which RDBBB could be maintained are discussed. The most probable mechanism appears to be “true” unidirectional block in the affected bundle branch, in which the refractory period for the retrogradely conducted impulse is shorter than that for the anterogradely conducted impulse.     

Second degree entrance block with supernormal conduction in intermittent ventricular parasystole

A patient with intermittent ventricular parasystole is reported in whom the presence of second degree entrance block with supernormal conduction was suggested for the first time. In this patient, ventricular extrasystoles with variable coupling frequently occurred. The QRS configuration of the extrasystoles was different from that of the parasystolic beats. When extrasystoles did not occur, the parasystolic beat was never seen because the conducted sinus impulse always reset the parasystolic rhythm. When an extrasystole occurred 0.52 sec or more after the preceding sinus beat, this extrasystolic impulse also reset the parasystolic rhythm. On the other hand, when an extrasystole occurred between 0.47 and 0.51 sec after the sinus beat, the parasystolic focus was protected from this extrasystolic impulse. When, however, an extrasystole occurred in a short terminal portion of the T wave of the preceding sinus beat, this extrasystolic impulse reset the parasystolic rhythm again, suggesting entrance block failure during the supernormal phase.     

Clinicopathological study of the heart and coronary arteries of autopsied cases from the community of Hisayama during a 10-year period. Part IV. QS waves in the precordial leads

During a ten-year period, from November 1, 1961, to October 31, 1971, 339 residents aged 40 years or over at death were nonselectively autopsied in a Japanese community, Hisayama town (mean autopsy rate: 84%). One or more standard 12-lead ECGs plus V4R and V7 electrocardiograms taken at periodic medical examinations were available for 308 of them. In 46 persons, QS waves were localized in one or more leads from V1 to V4. By transverse sectioning of the hearts, old myocardial infarction extending into the interventricular septum was found in nine of these 46 persons. Frequency of myocardial infarction cases in each category for QS localization was as follows: Lead V1 to V4, three of three; Leads V1 to V3, six of nine; Leads V1 and V2, three of 15; Leads V2 and V3, none of two; Lead V3, none of one; Lead V2, one of eight; and Lead V1, one of 25.     

Polarcardiographic study of inferior myocardial infarction: Global projection of heart vector

The sensitivity of electrocardiographic, vectorcardiographic and polarcardiographic criteria for inferior myocardial infarction was studied. ECG and Frank system VCG were recorded in 50 normal cases and 40 cases of inferior myocardial infarction, whose acute phase was documented by typical electrocardiographic and serum enzymatic changes. The records were made from one month to 16 years after acute attacks. Polarcardiograms were obtained by a specially-designed analogue computer from X, Y and Z signals of the VCG, and recorded at a paper speed of 1000 mm/sec by Mingograph. The polarcardiographic tracings were measured at every 5 msec after onset of the QRS wave, and plotted on the Aitoff's equal-area projection. In normal cases, the QRS vectors plotted on Aitoff's projection passed through the narrow area between 15 to 35 msec after the QRS onset.Electrocardiographic diagnosis of myocardial infarction was correctly made in 22 cases (55%), and by VCG the sensitivity was improved to 32 cases (80%). Polarcardiographic diagnosis was made in 33 cases (82.5%). Global plots of heart vector on Aitoff's projection were a useful display to visualize the sequential changes of heart vector. In inferior myocardial infarction, the QRS vector passed through the more superior portion to normal, and the diagnosis was accurately made in 33 cases (82.5%).     

Sequential changes of orthogonal electrocardiograms in progressive muscular dystrophy of the Duchenne type.

Sequential changes of orthogonal electrocardiograms in 70 patients with progressive dystrophy of the Duchenne type (PMD) were investigated. The patients were classified into eight stages from the mildest, S(1), to the severest, S(8), according to Swinyard-Deaver's criteria. The most prominent finding was a progressive reduction in R wave amplitude in Lead X (Rx) with advancing severity. It was considered that loss of electrical activity in the left ventricular free wall might be mainly responsible for the reduction in the Rx amplitude. An abnormal Q wave was frequently observed in each stage. Its occurrence remained essentially unchanged with the progression of PMD. Thus, the presence of a deep Q wave cannot serve as an index for assessing the heart involvement, but rather, we conclude that a reduction of the Rx amplitude can be a useful criterion for estimating the extent of cardiac involvement in PMD.