Echocardiographic assessment of pulmonary arterial pressure in children with complete right bundle branch block

The time interval between tricuspid valve closure and pulmonary valve opening, termed the isovolumic contraction time of the right ventricle, was evaluated echographically in 38 normal children and within 24 hours of cardiac catheterization in 53 children with congenital heart disease and normal conduction as assessed with the electrocardiogram. In the 53 patients with congenital heart disease, isovolumic contraction time was strongly influenced by right ventricular afterload, as defined by pulmonary arterial end-diastolic pressure (r = 0.87). It was possible to utilize isovolumic contraction time to separate patients with normal or elevated values for pulmonary arterial end-diastolic pressure. Similar correlations were demonstrated between isovolumic contraction time and mean pulmonary arterial pressure and calculated pulmonary vascular resistance. Evaluation of 15 children with complete right bundle branch block revealed values for isovolumic contraction time that did not significantly differ from those of patients with similar pulmonary arterial end-diastolic pressure but no conduction abnormalities. These findings indicate that serial echographic evaluation of the interval from tricuspid valve closure to pulmonary valve opening can give an accurate reproducible assessment of right ventricular afterload in many children with congenital heart disease and complete right bundle branch block.     

Exercise testing for detection of myocardial ischemia in patients with abnormal electrocardiograms at rest.

This review consists of two parts: (1) discussion of the electrophysiologic mechanisms that are believed to produce ventricular repolarization changes during the electrocardiographic stress test, and (2) clinical assessment of the electrocardiographic changes with stress in patients with an abnormal electrocardiogram at rest. In the first part, the mechanisms of S-T segment elevation, S-T segment depression, T wave changes and linked S-T and T wave changes are reviewed. In the second part, all electrocardiographic abnormalities at rest are grouped into four categories: (1) changes that mask the manifestations of ischemia, (2) changes that stimulate or exaggerate the manifestations of ischemia, (3) changes that have no important effect on the manifestations of ischemia, and (4) changes that reproduce the patterns of acute myocardial infarction after an apparent healing. The reported studies of electrocardiographic stress testing in patients who have abnormal electrocardiogram at rest are summarized.     

Goodpasture's syndrome in a patient with the nail-patella syndrome

A patient with the nail-patella syndrome in whom end-stage renal failure developed as the result of Goodpasture's syndrome is described. Lesions characteristic of both rare diseases were seen on renal morphology. It is postulated that the glomerular membrane alteration of the nail-patella syndrome predisposed to the development of antiglomerular basement membrane antibody and hence Goodpasture's syndrome. A review of the incidence of renal failure in the nail-patella syndrome suggests that renal involvement can no longer be regarded as benign and that immune mechanisms may be related to progressive renal disease in some cases.     

Evaluation of left ventricular contractile pattern by intravenous digital subtraction ventriculography: Comparison with cineangiography and assessment of interobserver variability

The accuracy and reproducibility of measurements of left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF) and regional wall motion obtained by digital subtraction ventriculography (DSV) were compared with values of direct cineangiography in 40 patients, 21 of whom were ambulatory. DSV was performed with a 1-second, 30-ml contrast injection, which yielded real-time fluoroimages composed of 512 × 512 pixels at 30 frames/s. Single-plane right anterior oblique LV volumes were calculated by area-length methods for both DSV and cineangiography. Wall motion was assessed as percent area shortening for 12 equal myocardial segments, with results classified as abnormal if greater than 2 standard deviations below the mean of 20 normal values. DSV exhibited close correlation with angiography for EDV (r = 0.88), ESV (r = 0.92) and EF (r = 0.93). Intravenous DSV and direct cineangiography were concordant in classification of LV contractile pattern in 436 of 480 (91%) myocardial segments. Measurements of DSV obtained by 2 observers showed close correlations for EDV (r = 0.88), ESV (r = 0.95) and EF (r = 0.94), and wall motion classification was in agreement in 434 of 480 (90%) LV segments. Artifacts induced by respiratory motion, persistence of contrast in the right ventricle or left atrium, or low cardiac output may have contributed to the discrepancies observed. These data indicate that DSV is accurate in assessing LV volume and EF, correlates well with cineangiography and exhibits good interobserver reproducibility.     

Addison's disease with adrenal enlargement on computed tomographic scanning. Report on two cases of tuberculosis and review of the literature

Two patients with Addison's disease related to urogenital tuberculosis had enlargement of one or both adrenal glands detected with computed tomographic scanning. Review of reports of adrenal size on computed tomographic examination suggests that adrenal enlargement in the presence of Addison's disease demands further investigation about the cause of the adrenal insufficiency.     

Correlation of continuous wave Doppler velocities with cardiac catheterization gradients: an experimental model of aortic stenosis

The purpose of this study was to use a canine preparation of experimental aortic stenosis to compare estimates of pressure gradient derived from continuous wave Doppler ultrasound with gradients measured directly by catheterization. Aortic stenosis was created in six mongrel dogs by placing an elastic band around the aorta. Eighty-eight different pressure gradients, ranging from 5 to 160 mm Hg, were produced by variable tightening of the aortic band. Pressure gradients were measured by micromanometer-tipped catheters placed in the left ventricle and aorta. Doppler spectral signals were simultaneously obtained using a 2.0 MHz nonimaging transducer placed directly on the surface of the ascending aorta. Doppler and pressure recordings were analyzed using a custom-designed software program to measure maximal instantaneous, mean and peak to peak gradients, as well as ejection and acceleration times. Maximal instantaneous Doppler gradient showed an excellent linear correlation with maximal instantaneous catheterization gradient (r = 0.98, SEE = 5.3 mm Hg). The correlation of Doppler-estimated maximal gradient to peak to peak catheterization gradient was also linear (r = 0.97, SEE = 6.2 mm Hg) but resulted in a systematic overestimation of pressure drop (mean overestimation = 9.0 mm Hg). Measurement of the Doppler gradient at mid-systole resulted in a more accurate correlation with the peak to peak catheterization gradient (r = 0.98, SEE = 6.1 mm Hg) and eliminated the problem of overestimation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Renal transplantation for patients with type I and type II membranoproliferative glomerulonephritis: serial complement and nephritic factor measurements and the problem of recurrence of disease.

Fourteen patients with membranoproliferative glomerulonephritis as their original kidney disease received 16 renal allografts. All 14 patients are alive, 11 currently have functioning allografts, and one graft was lost to recurrence of membranoproliferative glomerulonephritis. Originally depressed serum complement (C3) concentrations returned to normal soon after transplantation in those patients with no clinical evidence of recurrence. Two patients with type II membranoproliferative glomerulonephritis had recurrence of disease. Nephritic factor (C3NeF) was high in both these patients before they received their transplants and was absent soon thereafter. However, abnormally high levels were again detected in their course. The one recurrence of type I membranoproliferative glomerulonephritis was associated with depressed C3, Clq, C4 and factor B but without C3NeF activity. Despite warnings of "high risks/ and "high mortality" associated with renal transplants in patients with membranoproliferative glomerulonephritis, we, because of these results and a review of the literature, continue to recommend renal transplants from both living related (LRD) and cadaver (CAD) donors in otherwise suitable patients who have renal failure due to membranoproliferative glomerulonephritis.     

Absence of slow channel-dependent conduction within the His-Purkinje (bundle branch) reentrant circuit: a clinical and experimental study of the effects of verapamil

The effects of intravenous verapamil on intraventricular conduction and reentry within the His-Purkinje system were studied in 10 patients and 8 dogs using His bundle electrograms and the ventricular extrastimulus method. In the clinical study, ventricular stimulation was performed by applying stimuli of two times diastolic threshold current strength and in the dog study by applying stimuli ranging in strength from two times diastolic threshold strength to 40 mA. In the clinical study, verapamil was given intravenously as a bolus injection (0.075 to 0.15 mg/kg body weight) and in the dog study as a rapid infusion (0.7 to 1 mg/kg) over 10 minutes followed by continuous infusion at a rate of 0.014 mg/kg per min. Plasma verapamil concentrations ranged from 91 to 173 ng/ml (mean ± standard deviation 138 ± 27) in the clinical study and from 103 to 638 ng/ml (mean 459 ± 174) in the dog study. In both studies, verapamil produced no change in latency and intramyocardial (duration of QRS complex) and His-Purkinje (V₂-H₂ interval) conduction of even the earliest premature impulses delivered before the repolarization of the His-Purkinje system or ventricular muscle, or both, was completed; that is, some fibers might have been at the level of membrane potential at which conduction becomes wholly or in part dependent on the current flowing through the slow channel. Verapamil did not change significantly the determinants of reentry and did not abolish or modify the zone of reentry in any of the 10 patients.These results show that in patients with normal intraventricular conduction, slow channel-dependent conduction plays no role in the propagation of even the earliest premature impulses through the His-Purkinje reentrant circuit. In the absence of any evidence of slow channel-de-pendent conduction, one must assume that the slow propagation of very early premature impulses was mediated by incompletely reactivated rapid inward current system. These observations suggest that the system responsible for slow conduction cannot be recognized from the magnitude of conduction delay.     

Effect of lidocaine on escape rate in patients with complete atrioventricular block: B. Proximal his bundle block

Lidocaine was administered intravenously (a loading dose of 1.5 mg/kg body weight followed by a 3 mg/min infusion) to 10 patients with complete atrioventricular (A-V) block proximal to the His bundle and A-V Junctional escape rhythm. A-V block was not due to an acute myocardial infarction in seven patients (group I) and was due to an acute inferior wall infarction in three patients (group II). Lidocaine had either no or only a slight depressant effect on the rate of the escape pacemaker in patients in group I but caused severe bradycardia or asystole in two of three patients in group II. Lidocaine had no consistent effect on the atrial rate and did not change the QRS duration and H-V intervals in any patient. These observations are consistent with the results of animal studies that showed that lidocaine selectively depressed conduction in Ischemic or depolarized myocardium. The findings also suggest that the use of lidocaine without prior insertion of a pacemaker is unsafe in patients with acute myocardial infarction and complete A-V block proximal to the His bundle.     

Prazosin as initial antihypertensive therapy: Correlates of sympathetic function

Abnormal sympathetic function has been proposed as a factor in the development of essential hypertension. If this is the case, prazosin hydrochloride, which works by a selective, peripheral, antisympathetic effect—postsynaptic α blockade—may have an advantage over other antihypertensive agents. In this study, blood pressure response and measures of sympathetic and baroreflex function were followed in 13 hypertensive patients. Prazosin alone significantly reduced standing and sitting diastolic blood pressures without affecting pulse rates, plasma catecholamines or baroreflex slopes in all patients. The addition of a thiazide diuretic in persons who did not achieve goal blood pressure on prazosin alone was generally successful in reducing blood pressure to desired levels, and increased both plasma renin activity and aldosterone concentrations. No significant relation was apparent between specific characteristics of sympathetic function and response to prazosin as initial therapy, although patients responding tended to have initially higher plasma norepinephrine concentrations.     

Anomalous left coronary artery from the pulmonary artery: significance of associated intracardiac defects

Two patients with anomalous origin of the left main coronary artery from the pulmonary artery had an associated defect (one, critical pulmonary stenosis; the other, ventricular septal defect). They presented with signs and symptoms of the associated defect and the coronary anomaly was unrecognized. Both cases at autopsy lacked the usual large right coronary artery seen with this anomaly. The pathophysiologic features of the combined defects are described, their differences from the isolated anomaly are noted and their relation to surgery is discussed.     

In vivo correlation of thermodilution cardiac output and videodensitometric indicator-dilution curves obtained from contrast two-dimensional echocardiograms

In previous studies, indicator-dilution curves obtained by videodensitometry of contrast two-dimensional echocardiograms have shown close correlation with measurements of blood flow in vitro. In this study the technique was extended and contrast indicator-dilution curves obtained in vivo were correlated with simultaneous cardiac output measurements determined by thermodilution in eight dogs. Two-dimensional echocardiograms of the left ventricle were performed with the transducer on the myocardium during left atrial-pulmonary vein injection of 10 cc of a 1 X 10(-4) concentration of 30 mu diameter microballoons. A total of 148 injections were performed at 37 levels of cardiac output (1.70 to 7.90 liters/min) induced by alterations of left ventricular preload, isoproterenol and propranolol. Indicator-dilution curves were obtained from recordings of the analog signal of a linear videodensitometer focused on the left ventricle. Linear regression analysis between total area of the indicator-dilution curves and cardiac output yielded correlation coefficients (r) of 0.77 to 0.96 (mean 0.90) for individual dogs, and 0.65 for all cardiac output determinations in all dogs. Analysis of indicator-dilution curve area by the forward triangle-exponential decay method yielded enhanced individual coefficients of 0.90 to 0.97 (mean 0.94) with cardiac output and 0.61 for the group of animals. It is concluded that echographic indicator-dilution curves obtained from uniform size microballoons and videodensitometry may be obtained in vivo and correlate with cardiac output measurements.     

Coexistence of ventricular parasystole and ventricular couplets: mechanism and clinical significance.

In 78 consecutive patients with uniform ventricular ectopic complexes and without heart disease, ventricular couplets were present significantly more often when the coupling interval of ventricular ectopic complexes was variable than when it was fixed (P less than 0.04). In 69 consecutive patients with couplets, the prevalence of a variable coupling interval was significantly greater than that of (55 versus 14 cases; P less than 0.001). Among 55 patients with a variable coupling interval, ventricular parasystole was probable in 38 and possible in 17 patients. These results suggest that the association between ventricular couplets and parasystole is not coincidental. Of several possible mechanisms responsible for this association reentry within the parasystolic focus or its vicinity is the most probable. This may explain the observation that the couplets are seldom followed by consecutive ventricular ectopic complexes or ventricular tachycardia. If this hypothesis is correct, the clinical significance of ventricular couplets in the presence of ventricular parasystole may be similar to that of single reentrant ventricular ectopic complexes.     

Accuracy of combined two-dimensional echocardiography and continuous wave Doppler recordings in the estimation of pressure gradient in right ventricular outlet obstruction

Fifteen patients (median age 8.5 years) with fixed right ventricular outflow tract obstruction were evaluated by two-dimensional echocardiographically directed continuous wave Doppler ultrasound within 24 hours of cardiac catheterization. Pulmonary artery blood velocity measurements were determined from a real time spectral display of pulmonary artery flow profile and converted to pressure drop utilizing a modified Bernoulli equation. Use of both parasternal and subcostal imaging permitted more accurate detection of maximal flow velocity than did use of either approach alone. Gradients estimated from Doppler recordings correlated well with those measured at cardiac catheterization (correlation coefficient = 0.95, standard error of the estimate = 7.9 mm Hg) with a trend to slight underestimation of gradient in more severe obstruction. In three patients with combined valvular and subvalvular stenosis and one patient with right ventricular outlet obstruction due totally to a ventricular septal aneurysm, Doppler estimation of gradient provided an accurate assessment of total right ventricular-pulmonary artery gradient. Thus, continuous wave Doppler ultrasound combined with two-dimensional echocardiography provides a reliable noninvasive method of estimating pressure gradient in patients with right ventricular outflow tract obstruction.