P.049 Effects of Inhibition of Nitric Oxide Synthase on the Peripheral Arterial Waveform Response to Exercise

Presentations S39waveform.We investigated this during cardiac catheterisation, examining the effects of pacing and nitroglycerin (NTG) on estimation of central systolic pressure from the peripheral pulse.Methods: Patients undergoing coronary angioplasty (n = 11, aged 48 to 72 years) participated.A Millar SPC-454D or fluid filled catheter was placed in the aortic root and a pacing wire in the right atrium.Peripheral digital arterial waveforms (Finometer) and aortic waveforms were obtained at baseline, during pacing at 20 bpm above resting heart rate and during administration of NTG (10 and 100 mg/min, i.v.).Results: Pacing and NTG produced marked changes in central and peripheral waveforms, reducing central augmentation index from 40.4±6.2 to 22.6±8.9%and from 40.4±6.2 to 12.7±7.0%for pacing and NTG 100 mg/min respectively (each P < 0.01).At baseline and during all interventions, there was a close correlation between central systolic blood pressure and absolute finger systolic pressure at the point of late systolic augmentation (R = 0.95, P < 0.0001).The mean difference between measured central aortic systolic BP and that estimated from digital pressure was 2.2 mmHg SD 6.2 mmHg.Conclusions: These data suggest that central systolic blood pressure can be estimated directly from non-invasive finger pressure waveforms even during interventions such as pacing and NTG that produce a marked change in pressure waveforms.