Citations

BACKGROUND Quantitation of valvular regurgitation remains a challenge. The accuracy of quantitative Doppler is controversial, and its ability to measure regurgitant volume is unknown; therefore, it is not widely used. METHODS AND RESULTS In 120 patients (20 without regurgitation, 19 with aortic regurgitation, and 81 with mitral regurgitation), the stroke volume through the mitral annulus and left ventricular outflow tract were measured using pulsed-wave Doppler concurrently with left ventricular stroke volume calculated using left ventricular volumes measured by two-dimensional echocardiography Simpson's biapical method. Regurgitant volume and fraction were thus computed using Doppler or ventricular methods. In normal patients there were good correlations between Doppler and left ventricular measurements of stroke volume. Doppler regurgitant volume and fraction were 4.4 +/- 4.4 mL and 5.3 +/- 4.5%, respectively. In patients with aortic regurgitation, there were good correlations between Doppler and left ventricular measurements of stroke volume, regurgitant volume, and regurgitant fraction (r = 0.97, r = 0.95, and r = 0.93, respectively; p < 0.0001). In patients with mitral regurgitation, despite good correlations between Doppler and ventricular methods for stroke volume, regurgitant volume, and regurgitant fraction (r = 0.94, r = 0.93, and r = 0.94, respectively; p < 0.001), these variables were overestimated by Doppler. However, in the last 54 patients compared with the first 27, overestimation decreased significantly for regurgitant volume (5 +/- 10 mL versus 18 +/- 27 mL, p < 0.05) and regurgitant fraction (3.3 +/- 6.7% versus 6.2 +/- 6.8%, p = 0.05). CONCLUSIONS Quantitative Doppler can be performed in large numbers of patients in a clinical laboratory. Its potential limitation was identified as overestimation of mitral regurgitation, which is overcome with increased experience. Its achieved accuracy in mitral and aortic regurgitation allows measurement not only of regurgitant fraction but most importantly of regurgitant volume.

BACKGROUND The implications of hypotension occurring during dobutamine stress echocardiography have not been elucidated. We observed in some patients that hyperdynamic left ventricular function developed during dobutamine stress echocardiography and hypothesized that intracavitary obstruction was occurring and might account for hypotension in some patients. METHODS AND RESULTS Fifty-seven consecutive patients undergoing dobutamine stress echocardiography underwent pulsed-wave and continuous-wave Doppler examination of the left ventricular cavity at rest and at peak dobutamine infusion. The development of an intraventricular gradient with dobutamine stress was defined as a late-peaking left ventricular Doppler velocity profile that exceeded basal velocity by at least 1 m/sec. During dobutamine stress testing, left ventricular outflow velocity or intracavitary velocity increased in all patients. Obstruction occurred in 12 patients (21%, group 1). Group 2 was the remaining 45 patients. Peak velocities in group 1 ranged from 2.0 to 5.0 m/sec (mean, 3.5 m/sec), and the mean increase from velocity at rest was 2.3 m/sec. The mean change in systolic blood pressure was significantly lower in patients in group 1 (-15 versus 4 mm Hg, p = 0.02). When the 18 patients with an ischemic response to stress testing (evidenced by new or worsening wall motion abnormalities) were excluded from analysis, systolic blood pressure response was still significantly different for the two groups (-19 versus 2 mm Hg, p = 0.03). CONCLUSIONS Dynamic left ventricular obstruction is a new observation; it may develop frequently in patients undergoing dobutamine stress echocardiography. Obstruction rather than ischemia may explain a decrease in blood pressure during dobutamine stress echocardiography.

BACKGROUND The endothelium possesses the ability to modulate vascular tone by the release of vasodilators and vasoconstrictors, among them endothelium-derived relaxing factor (EDRF) and endothelin (ET). Abnormalities in EDRF generation have been demonstrated in various cardiovascular pathophysiological states. Moreover, a twofold increase in plasma ET concentration was reported in these disease states. Recent in vitro studies have suggested the interaction between these two endothelium-derived substances, suggesting that imbalance between the two may contribute to alternation in vascular tone characteristic of these disease states. Thus, the hypothesis of this study was that inhibition of endogenous EDRF will enhance the vasoconstrictor response to a twofold increase in plasma ET concentrations. METHODS AND RESULTS Experiments were conducted in three groups of anesthetized dogs. In group 1, ET-1 was infused intravenously to double circulating ET concentrations. Group 2 received both ET and NG-monomethyl L-arginine (L-NMMA), a competitive inhibitor of EDRF generation, and group 3 received a continuous infusion of L-NMMA alone. Twofold increase in plasma ET concentrations was characterized by an increase in systemic and renal vasoconstriction. The inhibition of EDRF markedly enhanced the vasoconstriction to ET specifically involving the systemic, pulmonary, coronary, and renal arterial circulations. CONCLUSIONS The present study demonstrates that inhibition of endogenous EDRF augments the vasoconstrictor property of ET and supports a functional role for the balance between endothelium-derived vasodilating and vasoconstricting factors in the regulation of vascular tone.

BACKGROUND The purpose of this study was to estimate survival and quality of outcome and assess factors associated with outcome for patients out 5 to 15 years from their Fontan operation. METHODS AND RESULTS We studied 352 patients who had the Fontan operation prior to 1985. The overall 1-, 5-, and 10-year survival was 77%, 70%, and 60%, respectively. The following factors were significantly associated with lower survival: univentricular heart or complex congenital anomalies other than tricuspid atresia, early calendar year of operation, heterotaxia syndromes, early age at operation, increased pulmonary artery pressure, atrioventricular valve dysfunction, and higher (worse) New York Heart Association class. Reoperations were necessary for 103 of the 352 patients. At least 20% of the survivors have or have had cardiac arrhythmias requiring antiarrhythmic medication or mechanical pacemaker insertion. Between 7% and 10% of the patients have had or had protein-losing enteropathy/hypoproteinemia. At 5 years postoperatively, 122 patients (34.7%) were alive with a better New York Heart Association functional classification than preoperatively. Fifty-eight patients (16.5%) were alive and in the same functional classification, but 126 (35.8%) died within the first 5 years or were in a worse functional classification. Thirty-nine patients were doing excellently and 29 patients poorly 5 years after the operation. Of the surviving patients, 43% can do as much exercise as their peers, whereas 3% are incapable of exercise. CONCLUSIONS To assure good functional long-term outcome in addition to survival, clinicians must exclude from selection for Fontan operation patients known to be at high risk for death or poor outcome.

Scalar electrocardiograms of 31 patients with double-outlet right ventricle (19 with and 12 without pulmonary stenosis) were correlated with the hemodynamic and anatomic findings. Atrioventricular conduction defects, intraventricular conduction delay, and counterclockwise frontal-plane loops were found less often than formerly reported. Counterclockwise frontal-plane loops were found with, as well as without, pulmonary stenosis. The presence or absence of left ventricular hypertrophy did not correlate with the severity of pulmonary vascular obstructive disease. Electrocardiographic evidence of left atrial enlargement was difficult to interpret. Additional intracardiac malformations could not be appreciated from the electrocardiographic findings. The predictive value of the electrocardiogram for the diagnosis of double-outlet right ventricle was considered to be low. In patients with double-outlet right ventricle without pulmonary stenosis, the electrocardiogram was not helpful in predicting the severity of pulmonary vascular obstructive disease.

Echocardiograms were performed on 20 children who were 1-14 years old. Ten children had secundum atrial septal defects (ASD 2°); four had partial and two had complete atrioventricular canal defects (AVC); and three had partial and one had total anomalous pulmonary venous connection (APVC). Twenty-eight normal children were also examined. Echocardiograms of nine patients with ASD 2° revealed increased right ventricular dimension index (RVDI) and abnormal (paradoxic) ventricular septal (VS) motion. The remaining patient with ASD 2°, who had a Qp/Qs of 1.2 (smallest in the series), had a normal echocardiogram. All four patients with APVC had increased RVDI, and three had abnormal VS motion. The patient with normal septal motion had associated mild aortic stenosis, but he too had a small left-to-right shunt (19%). The echocardiograms of two patients with partial AVC revealed features similar to ASD 2°, but in the third patient who had significant mitral regurgitation (MR) the VS motion was normal, indicating that the degree of associated MR influences the VS motion in this anomaly. The septal motion was normal in both patients with complete AVC. Three patients in the series had abnormal systolic anterior motion of mitral valve. Postoperative echocardiograms revealed persistence of increased RVDI and "paradoxic" VS motion.

Atrial septal defect (ASD) of the fossa ovalis type was found in 16 members of one family and confirmed in 15 members at autopsy or surgery or by cardiac catheterization. Sinus rhythm was present in 12 affected members, 11 of whom had electrocardiographic evidence of prolonged atrioventricular (A-V) conduction. Five other family members without ASD also had prolonged A-V conduction. The pedigree chart suggests that the syndrome ASD with prolonged A-V conduction is the manifestation of a single mutant autosomal gene with dominant effect, a high degree of penetrance, and some variation in expressivity. Earlier reports of familial ASD showing the autosomal-dominant pattern of inheritance reveal a similar frequency of prolonged A-V conduction among affected persons. The great majority of cases of ASD are sporadic, with little likelihood of recurrence in subsequent sibs or children. We suggest, however, that when ASD of the fossa ovalis type is accompanied by prolonged A-V conduction, the genetic prognosis may be drastically changed to a risk of almost 50% that the condition will recur in subsequent sibs or children of affected persons.

Simultaneous determinations of serum potassium and sodium, blood pH, blood pressure, and 12-lead electrocardiograms were obtained in hyperkalemic patients with chronic renal failure. Statistical investigation of the data showed a high correlation between serum potassium levels and ventricular repolarization abnormalities. "Mean intracellular potassium concentration" derived from total body potassium and total body water values was not accurate enough to show significant correlations to ECG changes and did not improve on the already significant correlations with serum potassium levels. Equations are presented which would permit the estimation of serum potassium levels (in a narrow range) from electrocardiographic findings in patients with chronic renal failure and suspected hyperkalemia.

Muscular obstruction to left ventricular outflow is a rare but serious occurrence. Eight cases in which this disease was anatomically proved are presented. The commonest symptoms are angina, dyspnea, and palpitations. Not uncommonly a family history of heart disease may be elicited. A systolic murmur along the left sternal border is the most characteristic physical finding, but a normal aortic second sound, the presence of third and fourth heart sounds, splitting of the second sound, and the absence of a diastolic murmur are all helpful clinical guides. Withdrawal pressures from the left ventricle reveal a characteristic infundibular pressure zone. Other hemodynamic findings include an anacrotic notch on the left ventricular pressure tracing, a rapidly ascending bisferious aortic pulse and a small compensatory beat after extrasystoles. Necropsy specimens reveal a grossly thickened interventricular septum as compared with normal and hypertrophied control hearts. Microscopic alterations are minimal. The etiology remains obscure but familial and developmental factors, either or both, appear to be implicated.

Direct surgical relief of diffuse subvalvular aortic stenosis has been accomplished in two cases by open operation through a left ventriculotomy.