ISSN:0009-7322    

出版商:OVID    

年代:1973

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1973

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

The three major coronary arteries of 10 normal human hearts were injected with differentially colored gelatin mass for histologic determination of the blood supply to the His bundle and proximal bundle branches. The His bundle was dually supplied by the A-V node artery and the first septal branch of the left anterior descending artery in nine hearts, but entirely by the A-V node artery in one. The proximal right bundle branch was supplied by both the A-V node artery and septal branch in five hearts, only the septal branch in four, and the A-V node artery alone in one. The anterior half of the left bundle branch was dually supplied by the A-V node artery and septal branch in four hearts, entirely by the septal branch in five, and the A-V node artery alone in one. The posterior half of the left bundle branch was supplied by the A-V node artery alone in five hearts, dually by the A-V node artery and septal branch in four, and by the septal branch alone in one. The blood supply to most of the human His bundle and its proximal branches is thus dual in origin, with anastomosis principally within the His bundle.

ISSN:0009-7322    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Pepine CJ, Wiener L: Circulation46:863, 1972. On page 866, in the first paragraph under “Discussion,’ the quote from Osler, “yielded promptly to amyl nitrate,’ should read “yielded promptly to amyl nitrite.”

ISSN:0009-7322    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Eighty-five patients with accelerated (preinfarction) angina are reported. Six suffered acute myocardial infarction awaiting catheterization and coronary angiography, so were not studied. Seventy-nine had coronary arteriography and other angiographic and hemodynamic studies. Fifteen of these 79 patients had normal coronary arteriograms; 64 had significant coronary artery obstruction. The clinical manifestations in 64 abnormal patients did not differ from those with normal arteriograms. Hemodynamic abnormalities correlated with the severity of arteriographic abnormalities. Of 70 patients with coronary artery disease, including the six not studied because of infarction, 48 were treated surgically with a mortality of 12.5%. Mortality for those 22 patients treated without surgery was 27%. Mortality could be correlated with certain risk factors: (1) congestive heart failure; (2) more than three-vessel coronary disease; (3) left ventricular end-diastolic pressure > 12 mm Hg; (4) cardiac index <2.7 liters/min/m2; (5) stroke index <35 ml/beat/m2; (6) estimated cardiac work (mean aortic pressure × cardiac index) <240 units; and (7) ejection fraction <0.50. Cardiac catheterization and angiography were performed without major complications in 97% of patients.

ISSN:0009-7322    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Left ventricular (LV) shape change during systole was characterized in nine patients with typical clinical findings of the systolic click syndrome (SCS) by means of cineangiographic measurements of three segmental diameters of the LV cavity and of the mitral valve ring (MVR) and contrasted with findings in eight patients with normal LV function. In the latter group, shortening of the proximal, midventricular, and apical segment diameters was comparable, averaging 38.6, 40.3, and 46.8%, respectively; MVR shortening averaged 31.8%. The velocity of fiber shortening, estimated as mean circumferential fiber shortening rate (mean FSR), was also similar in the three segments (1.66, 1.84, and 2.09 circ/sec). In patients with SCS, the extent of shortening and mean FSR in the proximal ventricular segment were consistently reduced (average 22.2%,P< 0.005; and 0.96 circ/sec,P< 0.025 respectively), and the MVR exhibited either reduced extent of contraction (four patients) or was unchanged or increased in diameter during systole (five patients). However, shortening of the midventricular and apical segments was normal, averaging 37.5 and 40.5%, respectively, as was the mean FSR in these segments (averages 1.60 and 1.70 circ/sec).These findings are consistent with a primary disorder of the myocardium in SCS localized to the inflow region of the left ventricle.

ISSN:0009-7322    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Thirty-seven patients (mean age 42.7 years) with angina pectoris (AP), ischemic myocardial abnormalities, and normal coronary arteriograms were followed for 4.1 years (mean). Twenty patients had typical and 17 atypical AP. Ten had abnormal serum lipids, and eight had abnormal glucose tolerance tests. Rest-to-exercise hemodynamics revealed increased left ventricular (LV) end-diastolic pressure (mean 11.2 ± 2.6 mm Hg → 19.1 ± 3.6,P< 0.05), while stroke-work index increased (+29%). LV ischemia was detected by abnormal lactate extraction with atrial pacing in 10 or ≧1 mm S-T segment depression during exercise or pacing in 27 patients. After a mean follow-up period of 4.1 years, AP decreased in 80% of cases and remained stable in the other 20% of cases. One patient died suddenly, and autopsy revealed normal coronary arteries and myocardium. In the remainder, complications of ischemia, i.e. progression of symptoms, infarction, and heart failure were absent. Seven patients restudied 4.5 years (mean) later had no changes in their previously documented hemodynamic abnormalities and normal coronary arteriograms.The fate of patients with AP and normal coronaries with ischemic LV abnormalities (ECG, metabolic, or hemodynamic) appears favorable. AP responds to nitrate and propranolol therapy. These long-term clinical observations with angiographic and hemodynamic restudies suggest a nonprogressive disorder.

ISSN:0009-7322    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Vagal stimulation inducing significant bradycardia did not precipitate ventricular fibrillation in any of 34 dogs subjected to ligation of the left anterior descending coronary artery. Vagal stimulation, however, did result in two distinct types of ventricular arrhythmias occurring at different times following coronary occlusion. Within 3 hours, couplets and salvos were provoked which were overdriven by pacing at slow rates. From 4.5 to 9 hours ventricular tachycardia resulted which was slower in rate than the intrinsic sinus rhythm and could be overdriven only by pacing at rates faster than the ectopic mechanism. The response to acetylcholine administration was similar to that of vagal stimulation. By pacing in the presence of complete heart block or by the use of beta-adrenergic blockade, bradycardia was shown to be the basis for the ventricular arrhythmias. Reentry is believed to be the mechanism for the ectopics provoked by bradycardia early after coronary acclusion, while enhanced Purkinje fiber automaticity may account for the late arrhythmias.

ISSN:0009-7322    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Nitroglycerin is generally believed to be contraindicated during acute myocardial infarction because the resultant decrease in coronary perfusion pressure and reflex tachycardia might extend the area of ischemia. To determine the effects of nitroglycerin and alterations in arterial pressure on the degree of myocardial ischemia, the left anterior descending coronary artery was occluded for repeated 15-min periods in closed-chest conscious dogs. The degree of myocardial ischemia was estimated by summating the S-T segment elevation (∑ST) recorded from 12 myocardial electrodes. Although heart rate increased and arterial pressure decreased, ∑ST after 15 min of coronary occlusion was 14 ± 3 mv (P< 0.02) less during nitroglycerin therapy than during control occlusions. When the same alteration in arterial pressure was produced by venous hemorrhage, ∑ST tended to be greater than during control occlusions (+14 ± 7 mv, NS); the difference between the nitroglycerin and hemorrhage interventions was highly significant (28 ± 9 mv,P< 0.02). ∑ST was also less than control when phenylephrine was administered in doses sufficient to increase arterial pressure 25 mm Hg (−16 ± 3 mv,P< 0.005) and 50 mm Hg (−15 ± 2 mv,P< 0.001). When the decrease in arterial pressure and reflex tachycardia induced by nitroglycerin were reversed by simultaneous infusion of methoxamine, ∑ST was greatly reduced from control (−50 ± 16 mv,P< 0.02) and was significantly less than that occurring during nitroglycerin alone (−25 ± 5 mv,P< 0.001). We conclude that nitroglycerin may be a useful agent during acute myocardial infarction, particularly when the fall in coronary perfusion pressure and increase in heart rate are prevented by the simultaneous administration of an alpha-adrenergic agonist.

ISSN:0009-7322    

出版商:OVID    

年代:1973

数据来源: OVID