Branko Furst MD FFARCSI is professor of anaesthesiology at Albany Medical College. and author of the book “The Heart and Circulation: An Integrative Model ” which describes in detail the inadequacies of the currently accepted ‘pressure propulsion’ model of the heart.
This page presents highlights of his paper “The heart: pressure-propulsion pump or organ of impedance? “
The paper lists many observed anomalies observed during isolated heart experiments, live surgical procedures, clinical trials and large patient studies. Standard interventions based upon the pressure-pump hypothesis turn out to be ineffective at best, and in many cases result in behaviour that is the exact opposite of that predicted by the model.
An overwhelming impression is created that the blood is not propelled around by a pressure pulse resulting from the contraction of the heart chambers.
- A study of over 3000 patients using intra-aortic balloon pumps showed no significant difference in outcome from a control group
- Drugs such as dopamine that are supposed to strengthen the heartbeat and increase blood pressure are found to have the opposite effect of decreasing pressure
- Beta-blockers are said to weaken ventricular contractions and slow down the heart rate and yet have proved to be effective in improving cardiac performance.
- Cross clamping used in surgery should have a disastrous effect on blood flow but actually increases it by up to 25%
- Children with only a single ventricle demonstrate increased blood flow instead of decreased
- Studies show that the output of the heart is largely unrelated to its activity
- Cardiac output during exercise is way beyond that permitted by theory
- Mechanical pumps have proved to be a resounding failure with recipients living for a few days only after transplant
“S A Thompson showed that in asphyxiated dogs, residual circulation continued for up to two hours after cardiac arrest, Other research has shown 20% to 40% increases in cardiac output after occlusion of thoracic aorta“
Experiments showed an inverse relationship between aortic pressure and arterial pressure; as pressure within the heart increased, so arterial pressure decreased.
The heart as a regulator
The relationship between the blood pressure inside the heart and outside is characteristic of a negative feedback control system typical of many regulation systems; the more the pressure rises, the more drastic the measures needed to bring it back down again.
An nice example is given of a bathtub filled from a tap whilst the water is allowed to exit via the plughole. The higher the level of water, the greater the exit speed of the water. Furthermore, the exit velocity is not controlled by the speed of the water coming out of the tap but rather the volume of water in the bath. So input speed is decoupled from output speed somewhat and the system has a smoothing effect on the flow.
My comment: The heart obviously works somewhat different from the bath in that a relatively smooth flow, with minor fluctuations, is transduced to a pulsatile, stop-start flow with a more or less constant volume of output per ‘beat’. Rather than think of this as an inevitable side effect or even drawback of pressure-pump flow, we can now consider it to be a fully developed functional feature serving some unknown yet essential purpose.
The blood in chick embryos is seen to be circulating before the heart has been formed and vortices are observed in the blood in between pulses.
“It increasingly is recognized that intracardiac blood flow patterns play a key epigenetic role in the heart’s embryonic morphogenesis“
“It has been confirmed experimentally that a blood vessel responds to increase in flow by automatic adjustment of its diameter until the flow is stabilized at a new rate.”
The heart is not a mechanical pump, forcing a viscous fluid around a complex and extensive circulatory system but instead serves to regulate and modulate the flow of an already existing circulation of blood which is mobilised by other means.
“The widely accepted pressure-propulsion circulation model fails to explain an increasing number of observed circulatory phenomena”
“Experimental and phenomenological evidence suggest the opposite, namely that the blood possesses autonomous movement sustained by the metabolic demands of the tissues at the level of microcirculation.“
Related pages: The Heart is not a Pump Blood Flow in the Heart
The Heart and Circulation: An Integrative Model
Author: Branko Furst
ISBN-10 : 144715276X
ISBN-13 : 978-1447152767
The Heart and Circulation: an Integrative Model – Branko Furst
The introduction to the book
The heart: pressure-propulsion pump or organ of impedance? – Branko Furst
Branko Furst’s Radical Alternative: Is the Heart Moved by the Blood, Rather Than Vice Versa? – Walter Alexander
Creative Folkestone Triennial 2021 | Circulation Revisited: The Circulation of Blood
Video interview with Branko Furst