We evaluated the effects of selective activation of H1 receptors on coronary hemodynamics in 16 patients divided into two groups: group A, 11 patients with atypical angina or valvular heart disease and normal coronary arteries, and group B, five patients with spontaneous angina, four of whom had significant (greater than 70% stenosis) coronary artery disease and one with normal coronaries. Selective H1 receptor stimulation was achieved by infusing 0.5 microgram/kg/min of histamine intravenously for 5 min after pretreatment with cimetidine (25 mg/kg). Heart rate was maintained constant (100 beats/min) by coronary sinus pacing and coronary blood flow (CBF) was measured by thermodilution. In group A, during histamine infusion mean aortic pressure fell from 99 +/- 5 to 77 +/- 4 mm Hg (mean +/- SEM, p less than .001), coronary vascular resistance (CVR) decreased from 1.07 +/- 0.17 to 0.82 +/- 0.14 mm Hg/ml/min (p less than .02), and CBF and myocardial oxygen consumption remained unchanged. None of the patients in this subgroup developed angina during histamine infusion. In group B, while no significant average changes in mean arterial pressure, CVR, or CBF were observed, two of the five patients (40%) developed angina during histamine infusion, accompanied by ST-T elevation, a decrease in CBF, and an increase in CVR. In one of these two patients circumflex coronary arterial spasm was angiographically demonstrated during histamine-induced angina. Our results suggest that stimulation of the H1 receptor induces a reduction of CVR, probably resulting from vasodilation of small coronary resistance vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

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A 70-year-old female was admitted for syncope preceded by chest pain. On admission ECG showed signs of myocardial ischaemia and cardiac troponin I (cTnI) was mildly elevated. Acute coronary syndrome without ST elevation was diagnosed. During hospitalization transthoracic echocardiography (TTE) revealed the presence of a round echogenic pedunculated mass adherent to the aortic valve. Cardiac catheterization revealed normal coronary arteries. According to the hypothesis that the lesion could be responsible for both acute coronary syndrome and syncope, surgical intervention was scheduled. The mass was removed and the histological examination revealed a cardiac papillary fibroelastoma (CPF). CPF is the most common tumour of the cardiac valves, it is often found incidentally but it can cause myocardial infarction, sudden death, syncope and stroke; its embolization is the most common complication. For symptomatic patients surgical excision is curative.

Coronary artery disease may rarely be due to vasculitis. Angina pectoris and acute myocardial infarction have been reported in patients with Takayasu's disease, polyarteritis nodosa, and thromboangiitis obliterans. TM In this article we report a case of Buerger's disease localized to coronary and internal thoracic arteries (ITAs) in a young nonsmoking woman. The diagnosis was made by histologic examination of the ITAs that were discarded at the time of bypass surgery.A 39-year-old woman had a 2-year history of epigasmc pain of unknown origin and sporadic episodes of typical angina for the past 8 months. Because of worsening of symptoms she underwent a treadmill exercise test. which showed signs of myocardial ischemia. The patient appeared to be otherwise in good health, without evidence of risk factors including diabetes mellitus, hypercholesterolemia, hypertension, obesity, or family history of isch-From the