Related Experiment Videos
Coronary effects of adenosine in conscious man
M Marzilli1, G A Klassen, P Marraccini
1Institute of Clinical Physiology, C.N.R., Pisa, Italy.
Insights
Adenosine administration in conscious humans safely increases coronary blood flow. This study measured coronary blood flow changes after adenosine injections, revealing a dose-dependent increase in both regional and total myocardial perfusion.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Adenosine is known to regulate myocardial perfusion in animal models.
- Limited data exists on adenosine's cardiovascular effects in conscious humans, especially via intracoronary administration.
Purpose of the Study:
- To assess the cardiovascular actions of adenosine in conscious humans.
- To measure total and regional coronary blood flow following intracoronary adenosine injections.
Main Methods:
- Six patients with normal coronary angiograms received intracoronary bolus injections of adenosine (0.1, 0.5, 1.0, 2.5 mg).
- Coronary blood flow was measured using a three-thermistor thermodilution catheter in the coronary sinus.
- Great cardiac vein flow and coronary sinus flow were simultaneously recorded.
Main Results:
- Intracoronary adenosine injections were well-tolerated with no significant adverse effects.
- A dose-dependent increase in great cardiac vein flow was observed, showing a linear relationship with log adenosine dose (r² = 0.951).
- Coronary sinus blood flow also increased linearly with adenosine dose (r² = 0.98), indicating effects beyond the directly perfused territory.
Conclusions:
- Intracoronary adenosine administration is safe in conscious humans.
- Adenosine effectively increases both regional and total coronary blood flow in a dose-dependent manner.
Abstract:
Adenosine has been reported to play an important role in several cardiac functions, including the regulation of total and regional myocardial perfusion. This hypothesis is based on extensive investigations in animal models, but very limited information is available on the cardiovascular actions of adenosine in conscious man and the effects of the intracoronary administration of adenosine are unknown. The purpose of this study was to measure total and regional coronary blood flow after bolus injections of 0.1, 0.5, 1.0, and 2.5 mg of adenosine into the left anterior descending coronary branch. A three-thermistor thermodilution catheter was advanced into the coronary sinus to measure simultaneously the great cardiac vein flow and the coronary sinus flow. Six patients with normal coronary angiograms and normal ventricular function completed the study. Intracoronary injections of adenosine were free from significant adverse effect and caused a dose-related increase of great cardiac vein flow. A linear relation was found between flow increment and the log of adenosine dose (y = 18.929x + 74.84, r2 = 0.951). The highest flow, measured after the maximal dose, was almost three times greater than control flow (155 +/- 2 vs 58 +/- 3 ml min-1, P less than 0.001). We also observed a flow response in the territory not directly exposed to adenosine, as indicated by a marked increase of coronary sinus blood flow that was linearly related to the adenosine dose (y = 29.113x = 112.635, r2 = 0.98). These preliminary observations suggest: (1) Intracoronary injections of adenosine in conscious man can be performed without significant adverse effects.(ABSTRACT TRUNCATED AT 250 WORDS)