ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The clinical spectrum of the sick sinus syndrome (SSS) is described in a series of 56 patients who demonstrated either persistent unexplained sinus bradycardia (group I: eight patients); sinus arrest (group II: 15 patients); or bradycardia with episodic supraventricular tachyarrhythmias (group III: 33 patients). Coronary disease was the most common form of heart disease where etiology could be determined, but in 25 patients no clear etiologic diagnoses could be established. Thirty-three patients showed associated electrocardiographic conduction disturbances. Symptoms were common and were produced by both bradycardia and tachycardia. Eight patients in the bradycardia-tachycardia group experienced cerebral embolization. Despite bother-some symptoms, only six of the 56 patients died over an average follow-up of 7 years, and only one of these deaths appeared related to an arrhythmia. Drug therapy of bradycardia was generally ineffective, but digitalis was frequently helpful in patients with tachycardia. Electrical pacing was uniformly successful in treating symptoms of bradycardia but was disappointing in preventing tachyarrhythmias.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Ultrasound echocardiograms from the septal and posterior left ventricular walls were displayed with a simultaneously recorded electrocardiogram, phonocardiogram, and indirect carotid pulse. These echoes differed in both amplitude and waveform. The contour of the posterior wall echo resembled an inverted ventricular volume curve, while the septal echo was of smaller amplitude and had a characteristic notched appearance. Most of the movement of the left ventricular walls relative to the ultrasound transducer was attributable to systolic contraction and diastolic expansion of the cavity. However, superimposed on this motion due to change in cavity size was movement of the left ventricle as a whole, first anteriorly toward the ultrasound transducer during late systole then posteriorly away from it at the beginning of left ventricular relaxation. These movements added to the amplitude of posterior wall motion but subtracted from the motion of the septum and were responsible for the notch in the waveform of this echo. Attachment superiorly to the aortic root might also have limited septal motion which was less near the base than nearer the apex of the left ventricle.The internal left ventricular dimension measured by ultrasound was standardized by using the mitral valve as a landmark and by recording the motion of the left side of the interventricular septum and endocardial surface of the posterior left ventricular wall simultaneously. This measurement was reproducible. In normal subjects, the ultrasonic dimension measured 4.40 ± 0.28 cm at the beginning of systole and shortened by 35.5 ± 3.9% at a rate of 1.22 ± 0.31 lengths/sec. By contrast, the average figures for six patients with primary myocardial disease were 6.96 ± 0.43 cm, 14.9 ± 4.2%, and 0.64 ± 0.11 lengths/sec. Calculation of such indices of left ventricular size and of rate and extent of myocardial shortening should be useful in the detection of impaired myocardial function and in following its progress.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Ventricular minor-axis dimensions were measured by echocardiography at end-systole (S8) and end-diastole (SD) in five groups of patients: (I) normal; (II) mitral stenosis; (III) compensated volume overload; (IV) idiopathic hypertrophic subaortic stenosis; and (V) congestive heart failure. Cardiac pump function was evaluated by determination of left ventricular volumes and ejection fraction (EF) from the echographic dimensions using formulae previously reported. The mean velocity of circumferential fiber shortening (VCF), a parameter of cardiac muscle performance previously obtained only by invasive methods, was determined from the echographic dimensions by the formula:[See Equation in PDF File]. The duration of minor-axis shortening (dt) was measured directly from the echocardiogram.Dimension and volume measurements in these groups of patients were similar to those reported in similar patients determined by angiographic methods. Measurement of the relative changes in echographic dimensions with systole (%&Dgr;S), EF, and VCFallowed separation of patients with clinical heart failure (group V) from normal subjects (group I). Patients in group II had reduced values for these parameters compared to group I. Those in III did not differ significantly, and those in IV had increased values. In general, VCF, EF, and %&Dgr;S showed similar trends, but individual patients sometimes differed. The findings reported here demonstrate the feasibility of evaluating ventricular function by a noninvasive method in a large group of ambulatory patients.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

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.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Seven patients with congenital mitral stenosis have been investigated with echocardiography using reflected ultrasound. In all cases the mitral stenosis was combined with other cardiovascular malformations. The results are compared with those obtained at clinical investigation, cardiac catheterization, and operation and/or autopsy. It is concluded that the method is of definite value in diagnosing congenital mitral stenosis, even when this is combined with other cardiovascular malformations. The method is also found to be of value in assessing the severity of mitral stenosis.Three patients have been investigated after mitral valvotomy. It is concluded that the findings at echocardiographic examination agree quite well with the clinical findings and with the results of postoperative cardiac catheterization in the evaluation of the result of mitral valvotomy.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Echocardiographic studies were performed on six patients with autopsy-proved aortic atresia and hypoplastic left ventricle and two patients with surgically proved tricuspid atresia and hypoplastic right ventricle. The findings were compared to those from the echograms of 50 normal newborns who served as a control group. The ultrasound measurements obtained in the normal newborns were as follows: mean right ventricular end-diastolic dimension, 1.3 cm (range, 1.0 to 1.7), mean left ventricular end-diastolic dimension, 1.6 cm (range, 1.2 to 2.0), mean left atrial dimension, 0.9 cm (range, 0.6 to 1.3), and mean left ventricular outflow tract dimension, 1.0 cm (range, 0.7 to 1.2). The mean velocities of closure of the mitral and tricuspid valves during passive filling of the ventricles were 53 mm/sec and 43 mm/sec. The ranges were 36 to 80 mm/sec for the mitral valve and 34 to 56 mm/sec for the tricuspid valve.In the patients with aortic atresia, the significant findings were a larger than normal right ventricular chamber (mean, 2.5 cm), a left ventricular chamber measuring less than 0.9 cm, and an absent or grossly distorted mitral valve echo. By contrast the patients with tricuspid atresia had very small right ventricular dimensions less than 0.6 cm, no demonstrable tricuspid valve echo, and a larger than normal left ventricle (mean, 2.3 cm). The above findings were diagnostic and were not confused with the normal newborn or other forms of congenital heart disease.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The effect of lidocaine on the ventricular fibrillation threshold was investigated in the anesthetized open-chest dog during paced supraventricular rhythm, during acute ligation of the anterior descending coronary artery, and during premature ventricular contractions. The minimum current (in milliamperes) required to induce ventricular fibrillation was determined by passing a train (100 Hz) of 10-14 constant-current pulses through ventricular epicardial electrodes during the vulnerable period of the cardiac cycle. Lidocaine was administered intravenously either as a sudden injection or as a “loading’ injection followed by a constant infusion. Following a single injection of 0.7 mg/kg the blood lidocaine decreased to half its original arterial concentration in 9 min. After the termination of a 50-60-min constant drip of 70 &mgr;g/kg/min which was preceded by a loading injection of 2 mg/kg, the blood lidocaine concentration fell to 50% of its original value in 31 min. Lidocaine at therapeutic blood levels (1.2-5.5 &mgr;g/ml) increased the fibrillation threshold during paced supraventricular rhythm and reversed the fall in fibrillation threshold accompanying acute myocardial ischemia and premature ventricular contractions. The present studies quantify the ability of lidocaine to reduce the vulnerability of the heart to fibrillation during supraventricular rhythm, acute ischemia, and premature ventricular beats and provide information concerning the metabolism of lidocaine in the anesthetized dog.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Ventricular function was evaluated in 18 patients prior to left ventriculography and selective coronary arteriography. Simultaneous left ventricular pressure (catheter-tip manometer) and dP/dt were recorded at resting heart rates and during tachycardia induced by right atrial pacing. Pressure-velocity curves were constructed from which Vmaxand maximum measured contractile element velocity (max VCE) were obtained. Vmaxand max VCEinitially increased with pacing-induced tachycardia in 17 of the 18 patients. Eight patients developed evidence of myocardial ischemia during atrial pacing. During the period of myocardial ischemia there was a decrease in Vmaxand max VCEin all eight patients despite constant or increasing heart rate. In the 10 patients who did not develop evidence of myocardial ischemia with pacing-induced tachycardia, Vmaxand max VCEcontinued to increase or remained constant with increasing rate. Peak left ventricular dP/dt increased coincident with the onset of myocardial ischemia in six of eight patients despite a fall in Vmaxand max VCEin all eight patients during the ischemic period. A highly significant difference was demonstrated between Vmaxvalues of patients with normal ejection fractions and patients with low ejection fractions, both at rest and during pacing-induced tachycardia.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

This study was undertaken to assess the effect of collateral circulation on myocardial blood flow (MBF) reserve (ability to increase myocardial blood flow with a stress that increases myocardial oxygen requirements). One hundred patients had MBF measured at rest and after isoproterenol. After classification by anatomic severity of coronary artery disease (CAI), the groups were further compared by presence or absence of collateral vessels, and whether the collaterals were intercoronary or bridge collaterals. Forty patients (group A) had no coronary artery disease demonstrated by cineangiography. The increase in MBF with isoproterenol for this group was 87% (P< 0.001). Fifteen patients (group B) had CAI of 175 or greater. These patients increased MBF 73% on infusion of isoproterenol, an insignificant difference from group A. Forty-five patients (group C) had CAI of 175 or less when an index of 300 represents no occlusive disease. Those with intercoronary collateral vessels (group C1, 2) were unable to increase MBF to the same extent as patients in groups A and B did. There was no difference between this group and those without collateral vessels and the same severity of disease. Fifteen patients with CAI of 175 or less (group C3, 4) had bridge collaterals and were able to increase MBF to a greater extent than those with no collaterals or with intercoronary collateral vessels. This same group of patients, in a parallel observation, showed less S-T-segment depression on treadmill exercise than patients with intercoronary collateral vessels.The data suggest that intercoronary collateral vessels contribute insignificantly, statistically, to myocardial blood flow reserve. Bridge collaterals, however, do seem to contribute in selected patients.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID