ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The phases of systole were measured in 51 patients with acute myocardial infarction and three control groups: (1) a group of 40 patients without heart disease, (2) a group of 23 patients admitted to a coronary care unit for chest pain, who did not have an acute myocardial infarction, and (3) a group of 16 patients with stable angina pectoris and arteriographically proven coronary atherosclerosis. In addition, serial measurements were made in the acute myocardial infarction group. Total electricalmechanical systole (QS2), the preejection period (PEP), and left ventricular ejection time (LVET) were measured in each patient from simultaneous recordings of the ECG, phonocardiogram, and carotid pulse tracing. The systolic and diastolic blood pressures and QRS duration were also measured. Corrections were made for heart rate where appropriate.The average PEP was elevated on the first day of myocardial infarction but was within normal limits thereafter. The LVET and QS2were significantly shortened until the fourth week of hospitalization. There was considerable overlap in the PEP values among the four groups. Eight patients died of acute myocardial infarction; the PEP was abnormally short in three (two of whom had cardiogenic shock), normal in two, and abnormally long in three. The PEP/LVET ratio separated the acute MI group from the normal group but not from the other two patient groups. Clinical class, digitalis, and infarct location did not produce characteristic changes in the systolic time intervals.A reduction in stroke volume is the most likely explanation for the reduction in LVET and QS2. The wide range in PEP values observed is best explained by alterations in the multiple determinants of PEP.The systolic time intervals do not appear to be useful as a diagnostic or prognostic tool in acute myocardial infarction.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The magnitude and time course of alterations in left ventricular size, end-diastolic pressure (LVEDP), and stiffness consequent to chronic volume overloading were examined in conscious dogs. A large infrarenal aortocaval shunt was produced surgically, left ventricular dimensions were measured by cineradiography using radiopaque beads implanted subendocardially, and LVEDP was measured via an indwelling catheter. In nine experimental and seven control animals, LVEDP was related to the left ventricular end-diastolic diameter (LVEDD) over a range of LVEDP produced by transfusion and bleeding. In control studies LVEDP averaged 6.7 ± 1.42 (SEM) mm Hg, LVEDD determined at 15 mm Hg LVEDP averaged 4.8 ± 1.13 cm, and the mean slope of linear stiffness curves was 45.9 ± 2.3 mm Hg/cm. Time-dependent changes in all of these parameters were observed following creation of the shunt: A progressive increase of LVEDP reached a maximum by 2 to 3 weeks, and when early postshunt studies (mean 5.2 days) were compared with late postshunt studies (mean 6.8 weeks) LVEDP had increased from 9.7 ± 1.2 to 18.9 ± 1.1 mm Hg (P< 0.01). There was a progressive, more gradual, increase in left ventricular size, LVEDD being 4.81 ± 2.4 cm in early postshunt and 5.34 ± 2.8 cm in late postshunt studies (P< 0.01). Left ventricular diastolic stiffness showed an increase from 50.2 ± 5.6 to 96.6 ± 10.7 mm Hg/cm between early and late postshunt studies, respectively (P< 0.01), and functional compliance was reduced. In six animals the shunts were closed; at approximately 1 week there was a substantial drop in LVEDP (9.5 ± 1.9 mm Hg), and although LVEDD were unchanged stiffness decreased to 58.6 ± 12.2 mm Hg/cm (P< 0.01). Observations up to 4 months after shunt closure suggested further progressive return toward normal of these parameters. It is concluded that chronic volume overloading in the normal dog causes a time-dependent shift to the right of the diastolic left ventricular pressure-dimension relation accompanied by a progressive reduction of diastolic compliance, and that these changes are at least in part reversible following correction of the shunt.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Epicardial mapping technics were used to locate the origin of ventricular ectopic beats produced by pacing and by the administration of ouabain and acetylstrophanthidin in pentobarbital-anesthetized open-chest dogs. The sequence of epicardial depolarization was determined with close bipolar reference and roving electrodes. The wave of excitation spread in concentric manner from driven points with the origin having the earliest time. Nonparasystolic unifocal ventricular tachycardia (UVT) was then aroused in nine dogs with ouabain or acetylstrophanthidin. Plunge electrodes were inserted for recording and stimulating of bundle of His and Purkinje fibers. Earliest epicardial ventricular activation of the UVT beats always occurred at or near the apex of the left ventricle. Purkinje fiber (PF) spikes from the region of earliest epicardial depolarization appeared just prior to ventricular activation. Pacing at this point produced QRS configuration almost identical to that during UVT. His bundle pacing normalized QRS configuration and suppressed UVT. Isolated right ventricular and left ventricular PF were perfused in the same tissue bath for microelectrode impalement. Infusion of ouabain increased the rate of automatic discharge of left ventricular PF before those from the right ventricle in each of five preparations. These studies suggest that digitalis-induced unifocal ventricular tachycardia originates below the His bundle from Purkinje tissue supplying the left ventricle and demonstrate that automaticity of canine PF from the left ventricle is preferentially enhanced by ouabain.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

His bundle electrograms were recorded in three patients with heart block who subsequently died. Serial sections of the conduction system were performed. Two patients had complete block distal to H with wide QRS and P-H intervals of 135 and 100 msec, respectively (normal 80-140 msec). Postmortem (PM) revealed relatively insignificant A-V nodal lesions and major destructive lesions of both bundle branches. The third patient had block proximal to H with left bundle-branch block and H-V prolongation. PM revealed amyloidosis of the A-V nodal approaches and fatty infiltration of the A-V node and His bundle. There were also fibroelastic lesions, with total disruption of the left and moderate involvement of the right bundle branch.The first patient also had sinus pauses as well as delay between what was felt to be posterior internodal tract depolarization and the P wave. PM also revealed arteriolosclerosis, mononuclear cell infiltration, and fibroelastosis of the SA nodal approaches.Block distal to H appeared to reflect total disruption of both bundle branches. Normal P-H intervals appeared to correlate with relatively insignificant A-V nodal lesions. Block proximal to H with bundle-branch block and H-V prolongation reflected multiple conduction lesions. SA block appeared to reflect involvement of the SA nodal approaches.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The involvement of all five offspring of consanguinous and hypertriglyceridemic parents (first cousins) is reported.Three sons and two daughters of this family have increased triglycerides, normal cholesterol, and normal or slightly increased phospholipids. Mother and elder daughter have abnormal glucose tolerance. Father and mother are hypertensive; father had recent development of myocardial infarction and gout. The two elder sons had myocardial infarction and repeated bouts of angina. All three male offspring of this family have gout and are being treated with xanthinoxidase inhibitor (allopurinol). Planar xanthoma was present in one son with myocardial infarction. No chylomicronemia was noted. The response to diet and Atromid-S was satisfactory.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Additional data are presented from the Veterans Administration Cooperative Study with respect to the 194 control and 186 treated male patients with initial diastolic blood pressures averaging 90-114 mm Hg. Attack rates and effectiveness of treatment were examined with respect to the following risk factors present at entry: (1) cardiovascular-renal (CVR) abnormalities, the prevalence of which was higher than in the general population of hypertensive patients; (2) diastolic blood pressure; and (3) age. Both attack rates and effectiveness of treatment increased directly with the number of these risk factors present at entry. Age and presence of CVR abnormalities at entry appeared to strongly influence subsequent attack rates, whereas entry level of blood pressure had a relatively smaller effect on attack rates. On the other hand, “effectiveness of treatment’ appeared to be most influenced by the initial level of blood pressure. Patients with prerandomization diastolic blood pressure in the range of 90 to 104 mm Hg derived relatively little benefit from treatment unless they had CVR abnormalities at entry or were over 50 years of age. A longer period of follow-up would be needed to assess the value of treatment in the lower risk subgroups.With respect to side effects, the incidence of mild hypokalemia, hyperuricemia, and elevated fasting blood sugar was significantly higher in the treated group. These and other side effects should be weighed against the benefit to be expected from treating hypertensive patients at low risk.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The left ventricular volume and the internal surface areas of noncontractile regions were measured by cineangiocardiography at 60 frames/sec in nine patients with a chronic localized noncontractile area of the left ventricle. Arteriosclerotic heart disease was proven in eight patients by means of coronary arteriography. Left ventricular end-diastolic pressure, stroke volume, ejection fraction, mean circumferential shortening, and cardiac output were also measured before and after removal of the noncontractile area and revascularization of the myocardium.The noncontractile areas, measured at end-diastole, ranged from 12 to 40% of the internal surface area of the left ventricle. Generally, impairment of the left ventricular function depended on the size of the noncontractile areas. The end-diastolic volume was approximately 150 ml/m2when the size of noncontractile areas exceeded 20-25% of the left ventricular surface area (r = +0.72;P< 0.05). The ejection fraction decreased as the size of the noncontractile areas increased (r = −0.81;P< 0.01). Following surgery, the left ventricular function, as well as the clinical condition, improved significantly, although the cardiac performance remained in the abnormal range in most patients. The ejection fraction increased (P< 0.05), and the percent circumferential shortening also improved (P< 0.05).Removal of the noncontractile area of the left ventricle and revascularization of the myocardium improved the cardiac performance and increased the sense of well being in these patients.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

A prospective study of 50 consecutive patients undergoing cardiac valve replacement was designed to determine the incidence, types, and predisposing factors to postoperative arrhythmias. Patients were monitored continuously for the first 7 days following surgery.Thirty-seven patients (74%) experienced a total of 66 episodes of arrhythmia. Supra-ventricualr arrhythmias were the most common (43 of 66; 65%). The most frequent specific arrhythmia was atrial fibrillation (21 of 66; 32%). Arrhythmias occurred 77% of the time within the first 48 hours of surgery.Of 25 factors evaluated preoperatively in each patient, only two were found to predispose to postoperative arrhythmias. These were: (1) previous cardiac surgery; and (2) elevated blood urea nitrogen.There were four hospital deaths, representinig a hospital mortality of 8%. No deaths were due to a primary arrhythmia.It is concluded that whereas arrhythmias are a very common complication of cardiac valve replacement, early detection and treatment has lessened their significance as a cause of postoperative mortality and morbidity.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Thirty patients with ventricular tachyarrhythmias, which had not responded to intensive therapy with up to five antiarrhythmic drugs, were treated with bretylium tosylate. All patients had recurrent ventricular tachycardia, and 12 had repeated episodes of ventricular fibrillation. In 17 patients the arrhythmias followed acute myocardial infarction. Bretylium was administered intramuscularly or intravenously, and most patients received 4-5 mg/kg every 6 hours. Eighteen patients responded satisfactorily to bretylium and suffered no further ventricular tachyarrhythmias while receiving the drug. Bretylium partially suppressed ventricular arrhythmic activity in five patients and had no beneficial effects in seven patients. Administration of bretylium soon after the development of arrhythmias and withholding of other antiarrhythmic drugs during bretylium therapy favored a good antiarrhythmic response. Hypotension followed bretylium administration in 19 patients but exceeded 20 mm Hg in only one patient. Transient initial increases in blood pressure and ventricular arrhythmic activity occurred in five and four patients, respectively. Six patients were discharged from the hospital on oral bretylium 600 mg every 6 hours, and all have remained free from major ventricular arrhythmias for up to 15 months. In these patients postural hypotension was a transient and parotid pain a persistent side effect.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID