Analysis of T wave changes by activation recovery interval in patients with atrial septal defect.

We examined the distributions of the activation recovery interval (ARI), which is correlated with the local action potential duration (APD), to clarify the origin of the repolarization changes in ASD. The ECGs, QRST isointegral maps and ARI isochronal maps of 21 children with ASD from 3 to 5 years old in age were studied in comparison with 21 age-matched normal children. A conventional and 87 unipolar body surface ECG were simultaneously recorded. The ARIs were determined from the first derivatives of the ECG waveforms. Abnormal ST-T patterns were observed in 11 of 21 ASD, but only in two normal children. The QRST maps of a split positive area pattern were seen in 15 of ASD but none of the normal. In the ARI maps, all the normal children exhibited a short-ARI area on the left and a long-ARI area on the right side of the chest. In 19 of ASD, the ARI distribution revealed a leftward extension of the long-ARI area on the anterior chest, a relative shortening on the right anterior chest, and a localized prolonged ARI on the left anterior chest. The results suggest that right ventricular (RV) volume overload in ASD produces a localized prolongation of the APD on the RV epicardium.

Augmentation of QRS wave amplitudes in the precordial leads during narrow QRS tachycardia.

INTRODUCTION: QRS morphology during narrow QRS supraventricular tachycardia in patients without ventricular preexcitation generally is considered the same as that seen during sinus rhythm. This study presents a new ECG observation that the QRS amplitude increased significantly in leads V2 through V5 during tachycardia. METHODS AND RESULTS: Using the same ECG machine and the same electrode patches applied to the same electrode positions, 12-lead ECGs during sinus rhythm and narrow QRS tachycardia were analyzed comparatively in 23 patients without ventricular preexcitation. Precordial QRS amplitudes were measured as the vertical distance from the peak of the R to the nadir of the S wave. The amplitudes also were measured during atrial rapid pacing and extrastimulation. Furthermore, ventricular excitation during sinus rhythm and tachycardia was studied using body surface mapping. Body surface distributions of QRS potentials and ventricular activation time (VAT) were displayed as maps. Gross area of QRS (AQRS, equivalent to the QRS amplitude) was compared during sinus rhythm versus tachycardia. During tachycardia, QRS amplitude significantly increased in leads V2 through V5, without any noticeable change in the transitional zone or QRS wave duration. Increase of QRS amplitude also was noted during atrial rapid pacing and extrastimulation. Gross AQRS values during tachycardia significantly increased in the left parasternal area, whereas QRS isopotential and VAT isochronal maps were similar during sinus rhythm and tachycardia, suggesting a minimal role of conduction delay in the increase of QRS amplitude. CONCLUSION: QRS wave amplitude significantly increased in leads V2 through V5 during narrow QRS tachycardia compared with QRS waves in sinus rhythm. Increase of QRS amplitude seemed unlikely due to a conduction delay within the ventricular myocardium.

Non-dipolarity of heart potentials estimated by magnetocardiography in normal subjects.

We studied non-dipolarity characteristics during ventricular excitation in normal adults and children by magnetocardiography (MCG) by recording magnetic field on the thorax. The source and currents of the electrical dipole from the onset up to 60 ms of ventricular excitation were analyzed in 16 adults and 5 children. A single equivalent current dipole (ECD) was estimated by Sarvas' formula for the sphere model at 1 ms intervals. The non-dipole value (NDV) was calculated from the magnetic field strength at each recording point and theoretically estimated by ECD, representing an index for the non-dipolarity. At 32-34 ms from the beginning of QRS, the mean NDV was a minimum in all subjects suggesting at least a non-dipole component during this period. High NDV (over 5%) were present in most subjects in both the early and late phase compared to this period. Thirteen of 16 adults had a high NDV in the early phase (9.3 +/- 3.0%, mean +/- SD) and all 16 subjects had a high NDV in the late phase (21.5 +/- 10.5%). All 5 children had high NDV in both the early (10.5 +/- 5.4%) and late phases (16.8 +/- 7.9%). A single ECD estimation by MCG showed a relatively low non dipolar component and MCG could be applied to the clinical evaluation of cardiac excitation in both normal and pathological conditions.

Precordial leads QRST time integrals for evaluation of right ventricular overload in children with congenital heart diseases.

It was previously shown that body surface QRST isointegral maps of the anterior chest were abnormal in patients with right ventricular overload and that the abnormalities varied with hemodynamic status. The QRST isointegral maps were first characterized by using a departure index map for normal controls. The study group consisted of 14 patients with pulmonary stenosis (PS), 20 with tetralogy of Fallot, (TOF) and 43 with atrial septal defect (ASD). The QRST isointegral maps of these three groups were compared with the data on 23 to 65 age-matched normal children. In mean departure index maps, the patients with right ventricular pressure overload (PS or TOF) showed an increase in departure index on the anterior midchest, while those of right ventricular volume overload (ASD) showed two maxima on the anterior and left lateral chest, with a trough-like negative area between them. Since the abnormal findings were seen on the anterior chest, we evaluated the diagnostic usefulness of QRST time integral values for precordial leads of the routine electrocardiogram (ECG) in a second part of this study. The precordial QRST time integral values from 9 patients with PS and 11 with TOF (0-2 years of age, mean 1.1 years) and 22 ASD patients (6-15 years, mean 10.1 years) were compared with those of the age-matched control children. The QRST time integral values of the precordial leads in right ventricular pressure overload were significantly increased in the right precordial leads (V1, V2). In right ventricular volume overload, the QRST time integral values of the V1, V2, V4, and V6 leads demonstrated a significant deviation from those of the control group. Therefore, a discrimination formula was constructed by using the values of these leads, and the criteria derived from this formula revealed good (98%) diagnostic accuracy. In detection of right ventricular overload, the QRST time integral values of the precordial lead ECG, if confirmed in a larger data set, may be useful as a simple screening method.

Diagnosis of right ventricular overload by body surface QRST isointegral maps in children with postoperative right bundle branch block.

The utility of body surface QRST isointegral maps (QRST-Imaps) for the detection of right ventricular (RV) overload was examined in children with postoperative development of right bundle branch block. In healthy children with no evidence of bundle branch block (n = 31), the QRST-Imap demonstrated a maximum at the left anterior chest and a minimum near the right shoulder with a single dipole distribution. The positive areas extended from the left anterior chest to the left back, and negative areas extended from the right anterior chest to the right back. Children with complete right bundle branch block but without heart disease demonstrated a QRST-Imap that was similar to that seen in normal children. In patients with RV overload (n = 15; 8 with ventricular septal defect and complicated anomaly and 7 with tetralogy of Fallot), the QRST-Imaps were abnormal and demonstrated double maxima, a rightward shift of the maximum, and extension of positive areas to the right chest. In the 10 patients who developed postoperative complete right bundle branch block, 4 had no evidence of RV overload by hemodynamic or echocardiographic assessment and demonstrated a normal QRST-Imap. In the six children who had residual RV overload during hemodynamic assessment, the QRST-Imap was abnormal. These results suggest that the QRST-Imap is a useful method for the detection of RV overload in pediatric patients complicated with conduction disturbances.

QRST isointegral map reflects the sudden reduction of right ventricular pressure after balloon pulmonary valvuloplasty.

To elucidate the mechanism of electrocardiographic changes due to right ventricular pressure overload, serial changes on body surface maps recorded in two children with valvular pulmonary stenosis before and after successful reduction of right ventricular pressure by balloon valvuloplasty (BVP) were studied. Body surface maps and 12-lead electrocardiograms were simultaneously recorded before and 1-1.5 hours, 8 hours, and 5 days after BVP. Before BVP, QRST isointegral maps showed either two maxima or an expanded single maximum on the right anterior chest. These abnormal characteristics become normal or near normal 1-1.5 hours after BVP. Electrocardiographic waveforms and QRS and ST-T isointegral maps showed minimal changes. Changes in QRST isointegral maps were observed near the center of the midanterior chest. These results suggest that increased right ventricular pressure caused a primary repolarization abnormality in the mid-anterior chest that was easily detected by body surface QRST isointegral maps.

Bovine herpesvirus meningoencephalitis association with infectious bovine rhinotracheitis (IBR) vaccine.

During 1992, on a farm in the Tokachi district of Hokkaido, Japan, approximately 20 Holstein-Friesian calves showed neuroparalysis and died within 7-10 days after routine vaccination. Six male calves, aged about 1.5 months, were submitted to our laboratory for pathological examination and diagnosed as acute or subacute necrotizing meningoencephalitis due to bovine herpes virus (BHV) infection. The main necropsy findings included a few hemorrhages or clots, and malacic lesions localized in the cortical to subcortical area of the cerebrum. Histopathological brain lesions were characterized by laminar or focal necrosis of neurons, accompanying macrophages, polymorphonuclear cell infiltration, severe astrogliosis, and perivascular cuffing in all six calves. Nuclear basophilic inclusion bodies, which showed positive reaction with immunocytochemical staining of BHV antigen, were observed in the necrotic neurons, astroglia and oligodendroglia in five affected calves. BHV antigens were also seen in the cell bodies and cell processes of the necrotic neurons, which was indicative of cell-to-cell propagation of infection. There was a general tendency for more severe lesions to be located at the cortex to subcortex of the cerebrum. Milder lesions were observed in the cerebellum and brain stem. These findings suggest that the infectious route to the cerebrum in the present cases was through the olfactory bulbs and/or along the meninges beginning from the ethmoid bone, rather than through the trigeminal ganglia route as had been emphasized in studies dealing with experimental infection.

The body surface QRST isointegral maps in infants with right ventricular overload.

Electrocardiographic criteria for right ventricular (RV) hypertrophy in infants generally exhibit low sensitivity in terms of diagnostic accuracy. We studied the QRST isointegral map (QRST-Imap) of body surface potential distribution for the diagnosis of RV overload in patients less than 2 years old. Patients with atrial septal defect (ASD), pulmonary stenosis (PS) and tetralogy of Fallot (TOF) were examined (RV overload group) and the findings of their QRST-Imaps were compared to those of age-matched healthy infants (NOR). QRST-Imaps in RV overload showed abnormal findings, with two maxima or a rightward shift of the maximum with increased amplitude, in contrast to one maximum at the left anterior chest with a single dipole pattern in the NOR group. ASD patients had two maxima with a decreased integral value between them. In PS, two maxima were also observed, with increased integral values of the right maximum as the RV systolic pressure was elevated. TOF patients showed a single maximum shifted to the anterior median line with increased amplitude. These results indicate that the findings of QRST-Imaps are of value in detecting the presence and pattern of RV overload in infants.

Criterion for early prediction of coronary artery involvement by clinical manifestations in patients with Kawasaki disease.

One hundred and thirty patients with Kawasaki disease were examined by the clinical symptoms and findings in order to predict the coronary artery involvement in the early stage. These patients were tested by the two-dimensional echocardiography iteratively from the acute stage and categorized into the following three groups: Normal coronary artery, transient dilatation of the coronary artery and aneurysm of the coronary artery persisting eight weeks or more after the onset of the illness. Eighteen clinical symptoms and findings within the 14th, 21st and 35th day of the illness were studied. As a result of analysis, a criterion for the early prediction of the coronary artery involvement by clinical manifestations was established as follows: The patients who satisfy the following or are highly suspectable of having a coronary artery involvement: Fever persisting for 14 days or more. Fever persisting for 10 to 13 days, and when two or more out of the following four conditions are satisfied: The age at the onset of the illness is under one year. The lowest value of hemoglobin is 10.0 g/dl or less. The highest white blood cell count is 14000/cmm or more. The lowest value of serum albumin is 3.5 g/dl or less. Two false negative cases (6.5%) were recognized in 31 of the high risk group. Twenty-two false positive cases (22.2%) were observed in 99 of the normal group. One hundred and six cases out of the 130 cases (81.5%) satisfied this criterion. Therefore, this criterion was concluded to be useful to predict the coronary artery involvement in the earlier stage of the illness.

Detection of coronary arterial lesions by two dimensional echocardiography in patients with Kawasaki disease.

A two-dimensional echocardiographic examination was conducted on 184 patients with Kawasaki disease iteratively from the acute phase to the convalescent phase. Aneurysms or dilatation of the coronary arteries were observed in 37 patients (20.1%). Among these 37 patients, 22 had persistent abnormality even after eight weeks from the onset. In the remaining 15 patients, abnormal findings disappeared within eight weeks. Coronary angiography was performed on all of these 37 patients and compared with the findings of echocardiography. In consequence, echocardiographic findings were concordant with those of the angiography in 35 patients. Therefore, the two-dimensional echocardiographic examination is thought to be a reliable noninvasive method for evaluating the coronary arterial lesions of Kawasaki disease in the acute phase.