Cardiac failure is defined as a clinical syndrome where the cardiac output is inadequate and fails to fulfill the metabolic demands of body or its able to do so, only at a raised filling pressure, causing the classical symptoms of exertional dyspnea.
Consider this simple equation,
A 70 kg normal human requires an EF of 60 % to supply blood to his total body mass. If his EF falls to 30 % , certainly he is going to struggle with reduced cardiac output by 50 %. Now , theoretically if he loses his weight by 50 % (70 to 35 kg ) in-proportion to the loss in EF, . . . isn’t likely , he goes back to the original ” comfort zone” again as his metabolic demands are declined by 50 % and hence easily managed with the severely compromised EF of 30 % .
Is this a scientific or quixotic logic ?
By all means , it appears the later is right ! but wait . . nothing is Idiotic in a true scientific democracy ! Human beings can live a near normal life with one kidney, one lung, half the liver function and brain function ! Nothing wrong in wondering why not , one can live comfortably with “half heart” function?(ie EF of 30 %)
Having said that ,cardiac failure is not a simple mathematics of EF % .It’s extremely important to understand cardiac failure is systemic disease (often an inflammatory reaction as well) which progress to a net catabolic sate .Numerous named and unnamed counter hormone response(ACE,NEP, BNP etc) retains salt and water.At some stage the body either adopts or mal-adopts to it.Countering or mimicking these hormones has been a major therapeutic strategy.(ACEI, ARBs )
The final end point of cardiac cachexia is nothing but extreme response of the body to reduce its weight (with Tumor necrosis factor /IL6) .Survival occurs with whatever available cardiac output that matches metabolic supply to tissue.
Now ,coming to the title discussion, If weight-loss is the ultimate compensatory mechanism in chronic HF , what about conditioned and monitored weight reduction regimen ?
The management of cardiac failure after addressing all specific problems like structural ,functional abnormalities plus or minus revascularization should include a mandatory exercise training program that help optimize the weight.Reducing total body mass is directly going to improve the cardiac function, or at-least make it static and might dramatically relive symptoms and increase survival.However , the beneficial effect of exercise is mainly attributed to improving muscle mitochondrial function and augmenting exercise capacity.
Where is the evidence coming from ?
A point of controversy !
There are few reports that suggest good-weight is essential as a body reserve during the catabolic state of HF.In fact, low fat and cholesterol was unwelcome in some statin and HF studies. Some provocative papers even suggested a paradox where weight loss could be counterproductive in HF (I strongly dispute this as do many others.)
Final message
Unfortunately , truths without evidence is worse than plain falsehood !
When heart as a pump is failing , we go for sophisticated drugs, ICDs CRT devices, variety of surgeries etc . Shall I say , none of them has conquered the inevitable. We know ,HF’s mortality and morbidity is next only to burden of cancer.Applying all our wisdom , intentional and monitored weight reduction may be best bet to unload the heart in many of the HF patients .Mind you, this comes free of cost ! and that is not the only reason it should be tested in every such patients .My own experience and interpretation of available data would suggest its going to work in all and the benefits are going to be overwhelminng in overweight patients .
Dear heart failure patients . . .Wishing you all a controlled weight loss and a happy life !
Dr.S.Venkatesan MD 