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[Gregg phenomenon and garden hose effect]
1Zentrum für Operative Medizin I Forschungsgruppe Experimentelle Chirurgie Universität Düsseldorf 40225 Düsseldorf, Germany. schipkej@uni-duesseldorf.de
Insights
Improved coronary perfusion enhances heart muscle oxygen use and function, a concept known as the Gregg phenomenon. This study differentiates it from the hydraulic
Area of Science:
- Cardiovascular Physiology
- Cardiac Mechanics
- Coronary Circulation
Context:
- Cardiac function influences myocardial oxygen consumption and coronary perfusion.
- The Gregg phenomenon describes how improved coronary perfusion increases myocardial oxygen consumption and contractile function.
- The 'gardenhose effect' offers a hydraulic explanation for the Gregg phenomenon.
Purpose:
- To differentiate the Gregg phenomenon from the 'gardenhose effect'.
- To critically evaluate both the Gregg phenomenon and the 'gardenhose effect' in cardiovascular physiology.
Summary:
- The Gregg phenomenon, observed 40 years ago, shows improved coronary perfusion enhances myocardial oxygen consumption and contractile function.
- Later experiments by Arnold et al. demonstrated improved ventricular function with increased perfusion pressure, termed the 'gardenhose effect'.
- This work aims to distinguish these related but distinct concepts in cardiac physiology.
Impact:
- Clarifies the mechanisms underlying the relationship between coronary perfusion and cardiac function.
- Provides a critical evaluation of established physiological phenomena.
- Enhances understanding of cardiac energetics and mechanics.
Abstract:
Under physiologic circumstances, cardiac function determines myocardial oxygen consumption and consequently coronary perfusion. Surprisingly, in a reverse direction, improved coronary perfusion also increased myocardial oxygen consumption and contractile function. This experimental finding, now 40 years old, is termed the Gregg phenomenon. Some 10 years later, in experiments by Arnold and co-workers, an isolated increase in perfusion pressure improved ventricular function. In this context, the term 'gardenhose effect' was coined, implying a hydraulic explanation of the Gregg phenomenon. In the following, we attempt to distinguish the Gregg phenomenon from the gardenhose effect and to critically evaluate them.