ISSN:0009-7322    

出版商:OVID    

年代:1974

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1974

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Biopsies of cardiac tissue were taken from patients undergoing surgery for coronary artery or valvular disease. All subjects were on maintenance doses of digoxin, which were stopped 48 hours before surgery. The ratios, heart:serum, for digoxin content were remarkably similar and the variance was small.

ISSN:0009-7322    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Five cases of recurrent, wide QRS complex tachycardia which could be terminated with phenylephrine are presented. These cases fulfilled all accepted criteria for ventricular tachycardia. Carotid sinus massage with and without edrophonium hydrochloride had no effect on the ventricular activity but selectively slowed the atrial rate in cases of atrioventricular (A-V) dissociation, or blocked retrograde conduction in cases of A-V association. The mechanism of action of phenylephrine remains unclear.These cases have many possible implications. Two of the most important are: 1) phenylephrine may be useful in terminating certain cases of ventricular tachycardia; 2) termination of an unknown, regular, wide QRS complex tachycardia by phenylephrine, and possibly other pressors, can no longer be taken as proof of a supraventricular mechanism.

ISSN:0009-7322    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Twelve patients with paroxysmal supraventricular tachycardia (PSVT) were studied before and after administration of 0.1 mg/kg i.v. propranolol. Echo zones for inducing atrioventricular (A-V) nodal reentry were determined using His bundle recording and the atrial extrastimulus technique. After propranolol the echo zone was abolished in two patients, decreased in one, unchanged in five, increased in two. In two patients echo zones appeared only after propranolol. Nine patients had episodes of sustained PSVT prior to propranolol. Following propranolol PSVT persisted in only five. In these five patients propranolol slowed the rate of PSVT.The data were analyzed by plotting A1-A2and H1-H2interval curves. On the basis of these curves the patients were separated into those with “dual pathways’ and those with “reflection.’ The effects of propranolol on both conduction patterns are discussed.In summary, the actions of propranolol in PSVT patients were variable. Potentially beneficial effects included slowing of induced PSVT, loss of the ability to sustain PSVT, and decrease or total elimination of echo zones. Potentially deleterious effects included potentiation of the echo phenomenon with either increase or development of echo zones.

ISSN:0009-7322    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Ten normal volunteers and 38 patients with acute myocardial infarction were evaluated by biplane gated blood pool scanning. The mean left ventricular end-diastolic volume in those with infarction was 125 ± 41 ml/m2compared to 82 ± 10 ml/m2in the normals. The left ventricular end-systolic volume was 82 ± 35 ml/m2compared to 35 ± 4 ml/m2, and the left ventricular ejection fraction 36 ± 8% compared to 56 ± 3% in the normals. Thirty-six of the 38 patients with infarction had an area of akinesis which ranged from 15 to 59% of the left ventricular wall. Patients with acute myocardial infarction were found to have a significant increase in left ventricular end-systolic volume and decrease in ejection fraction compared to normals. The end-diastolic volume was, however, increased only in those with an elevated left ventricular filling pressure or decreased cardiac index.Follow-up studies obtained in 20 patients between one week and three months following infarction showed that in the 14 who improved clinically, left ventricular ejection fraction significantly increased from 38 to 45% (P< 0.001) while in six who failed to show clinical improvement or worsened, left ventricular ejection fraction remained at 30%.Left ventricular ejection fraction was significantly greater and the extent of akinesis significantly less in the patients who survived compared to those who died.

ISSN:0009-7322    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Twenty-five patients had myocardial blood flow reserve determinations (percentage increase in myocardial blood flow with stress), treadmill exercise tests and coronary and bypass cineangiography pre- and postaortocoronary bypass surgery. Twenty of the patients had the postoperative studies performed three months after operation, three at two months and two at five and six months, respectively.Eleven of the 25 patients had all significant coronary artery obstructions (75% or greater) bypassed and all grafts were open at the time of restudy. Preoperatively, blood flow reserve had been abnormal in nine and all had positive treadmill tests. Postoperatively, all eleven patients had normal myocardial blood flow response to stress and treadmill tests were negative in ten (one patient was not restudied on the treadmill).In six patients, no patent grafts could be demonstrated. These patients continued to show abnormal blood flow reserve and positive treadmill studies.Eight of the 25 patients had partial revascularization in that some grafts were open, some closed, and some significantly occlusive lesions were not bypassed. Four of these eight patients had normal flow and treadmill studies and the remainder continued to have an abnormal response to one or both of the measurements.The relationship between treadmill exercise response, myocardial blood flow reserve, and graft patency was significant at the 0.005 level for patients with all grafts open or closed. No significant correlation was obtained between any of the measurements in those patients with partial revascularization.The data indicate that successful aortocoronary bypass grafting provides myocardial revascularization as reflected in a return to normal of the myocardial blood flow reserve and response to treadmill stress testing.

ISSN:0009-7322    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Improved global or segmental wall motion following revascularization suggests potential reversibility of ischemic left ventricular dysfunction in coronary artery disease (CAD). This study evaluates the effectiveness of post-extra systolic potentiation (PESP) to detect latent residual contractile function. Quantitative left ventriculography was performed in 15 patients with CAD (including seven with significant asynergy) and in three normal controls. During the ventriculogram, a single extra-systole was introduced by an R-wave coupled stimulator (R-stimulus interval averaged 398 msec, with an average mA of 2.4). PESP improved segmental axis shortening in 51 of 55 normal axes and 15 of 17 hypokinetic or akinetic axes. It also increased both ejection fraction and mean rate of circumferential fiber shortening in 17 of 18 patients. No significant arrhythmia occurred with this technique. A single interposed beat with PESP in one ventriculogram is a safe, effective method to detect residual potential contractile function in myocardium that may be hypokinetic or akinetic under conditions of the study.

ISSN:0009-7322    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

The use of roentgen videometry as a means of studying regional left ventricular wall dynamics and performance was evaluated in 32 patients undergoing coronary arteriography. Nine patients had normal coronary arteriograms and hemodynamic findings (group 1), 8 patients had generalized decrease in left ventricular contraction and abnormal hemodynamic findings (group 2), and 15 patients with coronary artery disease had regional wall dynamics abnormalities (group 3). Sixty-per-second determinations of wall thickness were performed in selected sites of the left ventricle. Measurements performed included end-diastolic wall thickness (EDTw), mean and peak rates of systolic wall thickening (m and p dTw/dt), and fractional systolic increase in wall thickness (&Dgr;Tw/EDTw). In patients with uniformly performing ventricles (groups 1 and 2), these parameters correlated well with other parameters of ventricular function. Best distinction between the “normal’ group (group 1) and the “abnormal’ group (group 2) was achieved when the rates of thickening (m and p dTw/dt) were utilized (P< 0.001). In patients of group 3, three types of abnormal regional wall dynamics could be determined and quantified objectively: hypokinesia (decreased p dTw/dt), akinesia (p dTw/dt = 0), and dyskinesia (p dTw/dt < 0). The severity of the abnormality of the wall dynamics correlated well with the presence or absence of a previous infarction on the electrocardiogram, and the anatomic location was strongly correlated with the distribution and severity of coronary artery lesions within a given ventricle.

ISSN:0009-7322    

出版商:OVID    

年代:1974

数据来源: OVID