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Using quantitative coronary arteriography, the luminal area was measured in the proximal, middle and distal third of a normal coronary vessel in basal condition and 15 min after 0.005 mg/Kg ic gallopamil (Group 1); 15 min after ic placebo (Group 2); 15 and 30 min after iv gallopamil at a dose of 0.03 mg/Kg (Group 3A) and 0.05 mg/Kg (Group 3B). A significant (p less than 0.001) vasodilation was observed in all segments in Group 1 and only in distal segment (p less than 0.05) in Group 3B. Neither did the heart rate, systolic blood pressure nor the coronary driving pressure show any changes. In the second section of this study, we analyzed the effects of the drug on coronary blood flow and resistance in 8 patients without clinical and/or objective evidence of coronary artery disease. Using thermodilution technique, the coronary sinus blood flow (CSBF) and coronary resistance (CR) were measured in basal condition and 5, 10, 15 and 30 min after 0.05 mg/Kg iv gallopamil. We observed a significant (p less than 0.001) increase of CSBF after 10 min and a significant decrease of CR after 10 min (p less than 0.001) and 15 min (p less than 0.05). In conclusion, our results suggest that the anti-ischemic effect of gallopamil can be related not only to the reduction of myocardial oxygen requirement, but also to an improvement of coronary blood flow with a decrease in coronary resistance.

This study analyses the static and dynamic characteristics of the flow curves obtained by continuous wave Doppler flow velocity analysis in the internal mammary artery (IM) under normal conditions and after left anterior descending coronary artery by-pass. The IM flow velocity curve has the characteristics of a muscular artery both in basal conditions and during hyperventilation and Valsalva manoeuvre. On the other hand, the by-passed IM shows a typically phasic flow velocity curve, the diastolic flow prevailing over the systolic as is commonly the case in the coronary circulation. This curve also shows variations characteristic of the coronary circulation during Valsalva manoeuvre, whereas it is not affected by the alterations induced by hyperventilation in the area of the respiratory muscles. Continuous wave Doppler flow analysis of the by-passed IM can therefore be considered a reliable method for evaluating coronary flow in man. The fact that this method is non-invasive makes it obviously advantageous and widens its field of application not only to strictly diagnostic evaluations but also to physiopathological and therapeutical ones.

The effect of intracoronary and intravenous propranolol on coronary vasomotion was evaluated in 30 patients with coronary artery disease. Luminal area of a normal and a stenotic coronary segment was determined at rest, during supine bicycle exercise and 5 min after 1.6 mg sublingual nitroglycerin administered at the end of the exercise test using biplane quantitative coronary arteriography. Patients were divided into 3 groups: Group I (n = 12) served as control Group II consisted of 10 patients with intracoronary administration of 1 mg propranolol and Group III of 8 patients with intravenous administration of 0.1 mg/kg propranolol prior to the exercise test. In the control Group there was coronary vasodilation (+23%, p less than 0.01) of the normal and coronary vasoconstriction (-29%, p less than 0.001) of the stenotic vessel segment during bicycle exercise. After sublingual administration of 1.6 mg nitroglycerin there was vasodilation of both normal (+40%, p less than 0.001 vs rest) and stenotic (+12%, NS vs rest) segments. In Group II intracoronary propranolol was not accompanied by a change in coronary area but both normal (+13%, p less than 0.05) and stenotic (+22%, p less than 0.05) segments showed coronary vasodilation during bicycle exercise. After sublingual nitroglycerin there was further vasodilation of both normal (+31%, p less than 0.001 vs rest) and stenotic (+45%, p less than 0.01 vs rest) arteries. In Group III intravenous administration of propranolol was associated with a decrease in coronary luminal area of both normal (-24%, p less than 0.001) and stenotic (-41%, p less than 0.001) segments. During dynamic exercise there was coronary vasodilation of both segments when compared to the data after intravenous injection of propranolol but there was no change in luminal area (normal vessel-2%, NS vs rest; stenotic vessel-3%, NS vs rest) when compared to the resting data. After sublingual administration of 1.6 mg nitroglycerin both normal (+21%, p less than 0.001) and stenotic (+46%, p less than 0.001) segments showed coronary vasodilation. It is concluded that supine bicycle exercise in patients with coronary artery disease is associated with vasodilation of the normal and vasoconstriction of the stenotic coronary arteries. Intravenous administration of propranolol is followed by coronary vasoconstriction of both normal and stenotic coronary arteries probably due to secondary mechanisms (reduction in heart rate and contractility) because it is not observed after intracoronary injection of propranolol and it is overridden by bicycle exercise and sublingual nitroglycerin.