Pharmacodynamic monitoring during acute intervention in ischaemic heart disease using a new echo-Doppler device

1. We have utilised a new non-imaging echo-Doppler cardiac output device, using the principle of attenuated compensated volume flow (ACVF), to assess the cardiovascular effects of atenolol and buccal nitroglycerin (NTG) in a placebo-controlled study of 30 patients with coronary disease. 2. Atenolol (4 mg i.v.) reduced heart rate, cardiac output and time-averaged mean aortic velocity (P less than 0.01) and increased systemic vascular resistance (P less than 0.01). 3. Buccal NTG (5 mg) reduced systemic mean arterial pressure (P less than 0.01), cardiac stroke volume (P less than 0.05) and stroke length (P less than 0.01). 4. Thus although both drugs reduced time-averaged aortic velocity (an index of cardiac performance), the concomitant reduction in cardiac stroke length and tachycardia suggested sub-optimal cardiac filling for buccal NTG, whereas for atenolol (with the associated increased systemic vascular resistance but unchanged stroke length) attenuation of sympathetic stimulation at cardiac beta-adrenoceptors. 5. The ACVF method of cardiovascular monitoring should prove useful in human pharmacodynamic studies.