Leslie Wiener

Thromboxane release during pacing-induced angina pectoris: possible vasoconstrictor influence on the coronary vasculature.

We developed a radioimmunoassay for plasma thromboxane B, the metabolite of the coronary vasoconstrictor thromboxane A,. To see if thromboxane A, is produced during myocardial ischemia, we used atrial pacing to study 14 patients with greater than 75% occlusive coronary artery disease proved by arteriography. Paired samples were taken from the coronary sinus (CS) and an artery (A) for lactate and thromboxane B, analysis before pacing. During and after pacing at 140 beats/min, sampling was repeated. Before, during, immediately after and 10 minutes after pacing, percent myocardial lactate extractions (A-CS/A × 100) were 29.3 ± 3.7%, −21.1 ± 12.8%, −74.3 ± 20.3% and 25.1 + 3.5%, respectively (all changes p < 0.01). Before pacing, five patients had detectable coronary sinus or arterial thromboxane levels. During pacing, 18% and 40% increases occurred in coronary sinus and arterial blood, respectively (0.8 ± 0.1 to 0.9 ± 0.2 pmol/ml, and 0.5 0.2 to 0.7 ± 0.2 pmol/ml). Immediately after pacing, increases of 204% and 132% occurred in the coronary sinus and arterial blood (p < 0.05), respectively (2.3 ± 0.9 pmol/ml and 1.2 ± 0.4 pmol/ml). Ten minutes after pacing, thromboxane B, returned to prepacing levels. These data indicate that thromboxane A, is produced during pacing-induced myocardial ischemia and could alter regional coronary blood flow.

Angina pectoris in patients with normal and abnormal coronary arteriograms

Abstract Ten patients with typical angina pectoris and normal coronary arteriograms were evaluated. Hemodynamic measurements and clinical features were analyzed and compared to those in a similar group of patients with angina secondary to demonstrable coronary artery disease. Both hemodynamic and clinical abnormalities were observed in those patients with angina and normal coronary arteries. However, with the exception that exercise elicited angina and electrocardiographic changes more consistently in the group with coronary artery disease, there were no significant differences between the two groups.

Bilateral carotid sinus nerve stimulation in the treatment of hypertension

Abstract Bilateral carotid sinus nerve stimulation induced significant blood pressure reduction in each of 8 patients with severe essential diastolic hypertension which was previously uncontrolled despite a triple antihypertensive drug regimen. The acute hemodynamic response to bilateral carotid sinus nerve stimulation indicates that the procedure induces its antihypertensive effects as the result of both alpha and beta adrenergic blockade. It appears that the procedure is a useful means of controlling diastolic hypertension, on a long-term basis, especially in patients whose blood pressure is inadequately or incompletely controlled with antihypertensive drugs alone. In those instances in which bilateral carotid sinus nerve stimulation does not by itself reduce diastolic hypertension to normotensive levels, the response to antihypertensive drugs may be substantially enhanced.

Relationship of Anginal Symptoms to Lung Mechanics during Myocardial Ischemia

The anginal syndrome (AP) typically includes sensations of chest tightness or difficulty in breathing. Left ventricular (LV) dysfunction during myocardial ischemia incident with AP is now well documented. Since secondary alterations in lung mechanics could relate to these symptoms, we examined airway resistance (Raw), lung volume (TGV), lung compliance (CL), and LV pressure-volume relations during pacing-induced AP. LV end-diastolic pressure (EDP) increased suddenly with AP, (mean + 41%, p < 0.01), without change in end-diastolic volume (EDV). LV distensibility (EDV/EDP) decreased abruptly, (–37%, P < 0.01), with reduction in airway conductance (1/Raw/TGV), (–40%, P < 0.05), and CL (–27%, P < 0.05). When AP was relieved, these changes returned toward preangina levels. Ischemia-induced LV dysfunction abruptly increases LVEDP. The resulting increased pulmonary capillary pressure effects an alteration of lung mechanics consisting of increasing Raw and reduced CL. The changes in ventilatory effort which ensue...

Electrical induction of atrial fibrillation. An approach to intractable atrial tachycardia.

Abstract A case of atrial tachycardia, refractory to medical therapy and persisting for three months, is reported. Deliberate conversion to atrial fibrillation by electrical stimulation of the right atrium was achieved together with control of the ventricular rate by pretreatment with digitalis. The method and possible indications for its use are described.

Myocardial infarction without obstructive coronary artery disease

Abstract The present report describes five cases of transmural myocardial infarction occurring in patients without occlusive coronary artery disease or other discernible abnormalities. It is apparent from these cases and others described in the literature that such patients may present with or without angina and, in some, the clinical course will be complicated by recurrent infarction and/or significant residual myocardial dysfunction. At present the exact incidence and natural history of this syndrome is unclear. Undoubtedly the increasing application of coronary arteriography will identify many more such patients. Delineation of the genesis and the full clinical spectrum of myocardial infarction without coronary artery disease warrants further investigative attention.

The syndrome of cervical aorta. Report of a case and review of the previous cases.

Abstract A case of cervical aortic arch is presented, and the previous cases are reviewed. It is felt that bedside diagnosis should now be possible. It is suggested that the syndrome be strongly suspected in any patient exhibiting a pulsatile mass in the lower right cervical region associated with symptoms of vascular ring.

Effects of the Valsalva maneuver on myocardial ischemia in patients with coronary artery disease.

The influence of the Valsalva maneuver (VM) on myocardial ischemia was evaluated in 24 patients with coronary heart disease. Clinical and hemodynamic responses to the VM were studied during acute ischemia manifested by angina pectoris with transient left ventricular (LV) dysfunction and compared with responses during nonischemic intervals.In the absence of evidence for acute ischemia (angina and increased LV end-diastolic pressure), six patients had abnormal hemodynamic responses to the VM. Five had lack of systolic pressure overshoot and in one, systolic pressure did not decline during straining. When the VM was performed during an ischemic episode, 14 patients had abnormal responses (12 with lack of overshoot in phase IV and two with lack of systolic pressure decline in phase II). In 18 patients a prompt decline in LV end-diastolic pressure occurred with the disappearance of angina during the VM. These changes uniformly occurred during the latter part of straining (VM phase II) as cardiac size and systolic pressure declined. No adverse effects occurred when a VM was performed during acute ischemia.Our observations suggest that the VM abruptly reduces determinants of cardiac oxygen demand, relieving acute ischemia without harmful effects.

Monitoring tissue oxygenation of the heart after myocardial revascularization

A polarographic technique capable of simultaneous monitoring of myocardial tissue oxygen tension (MPO2) and intramyocardial electrograms by way of the same electrodes has been developed. Initially, the method was evaluated in dogs to verify the appropriateness of the directional changes of MPO2 in function of selected determinants of myocardial oxygen supply (regional coronary blood flow, arterial blood oxygen tension) and demand (heart rate, force of ventricular contraction). A combined reduction of MPO2 and elevation of the S-T segment in the corresponding electrograms was observed only when a 50 percent or greater reduction of blood flow to the sampled area was effected. Subsequently, in nine patients undergoing aortocoronary bypass surgery, MPO2 was measured from 48 areas for 2 weeks postoperatively. In 11 normal and 31 revascularized areas, MPO2 increased during the postoperative period. In four areas subsequently found to be supplied by occluded grafts MPO2 decreased from 12.7 +/- 3.1 (mean +/- standard error) to 10.1 +/- 3.3 mm Hg (P less than 0.05). In two areas, MPO2 decreased during the 3rd postoperative day from 16 to 3 and from 14 to 4.2 mm Hg, respectively. This reduction was attended by a significant rise in the S-T segment of the corresponding electrograms. This finding preceded by 24 hours standard electrocardiographic evidence of myocardial infarction. This technique appears to be sensitive and reliable, and thereby capable of enhancing the management of patients during the high risk early postoperative period after coronary bypass surgery.

LEFT VENTRICULAR FUNCTION IN MAN FOLLOWING THIOPENTAL

Several investigators1-5 have agreed that cardiac output, stroke volume, and systemic blood pressure decrease following thiopental administration in man. These changes have been ascribed to a reduced vasomotor tone, impairing venous return. However, there has been no direct evidence of intrinsic effect of thiopental on myocardial function in man. Although thiopental effects a reduction in contractile force of the isolated mammalian heart6 and of the right ventricle in the dog,? no intracardiac measurements of left ventricular function in man have been made during thiopental anesthesia. TABLE 1 Clinical D a t a of Patients S tud ied