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Absolute left ventricular volume changes after sublingual nitroglycerine and nifedipine intervention
Summary
Sublingual nitroglycerine significantly altered cardiac output and stroke volume in patients with ischaemic heart disease. Nifedipine only affected systolic blood pressure, showing this non-invasive technique can measure drug effects.
Area of Science:
- Cardiovascular Medicine
- Nuclear Cardiology
- Pharmacology
Background:
- Ischaemic heart disease (IHD) necessitates understanding vasodilator effects on cardiac hemodynamics.
- Accurate, non-invasive methods are crucial for evaluating drug efficacy in IHD patients.
Purpose of the Study:
- To assess the haemodynamic effects of sublingual nitroglycerine and nifedipine in IHD patients.
- To evaluate the utility of gated blood pool scintigraphy for measuring in vivo haemodynamic changes.
Main Methods:
- Two groups of 20 IHD patients received either nitroglycerine or nifedipine.
- Gated blood pool scintigraphy was used to measure left ventricular (LV) volumes, stroke volume (SV), cardiac output (CO), heart rate, and systolic blood pressure (SBP).
- A geometric method corrected LV activity for tissue attenuation for direct LV volume measurement.
Main Results:
- Nifedipine significantly decreased SBP (mean decrease of 11 mmHg) but did not significantly alter other haemodynamic parameters.
- Nitroglycerine significantly changed most parameters, decreasing mean CO by 8% and mean SV by 16%, excluding LV ejection fraction.
- A control group (5 IHD patients) demonstrated excellent repeatability, validating the measurement technique.
Conclusions:
- Sublingual nitroglycerine induces significant haemodynamic alterations in IHD patients, impacting SV and CO.
- Nifedipine demonstrates a more localized effect, primarily on SBP.
- Gated blood pool scintigraphy offers a reliable, non-invasive method for assessing the in vivo haemodynamic effects of cardiac drugs in IHD.