What are the factors other than EF % that determine functional capacity in cardiac failure ?
In our experience we have found the following factors contribute immensely to the functional capacity of cardiac failure patients
- LV filling defects (30 % of DCM have significant LV relaxation defects )*
- Integrity of RV function
- Mitral valve competence(Even a mild MR can be important .It lowers the threshold for pulmonary congestion )
- Severity of Pulmonary hypertension
- Lung Function *(Restrictive PFT common , gross cardiomegaly can reduce lung space )
- Basal exercise capacity .
- Skeletal muscle function (Mitochondrial training )*
- High body weight
- Will power and self esteem *
- Spouse support and motivation
* May have major Impact on functional capacity
Physicians and even cardiologists are obsessed with EF % to a large extent . My guess is , it is not likely to end in the near future . The irony is , we have passed it to our colleagues (Like anesthetists !) and patients as well .( for various reasons )
Please remember , there are at-least 10 factors that are important in the genesis of symptoms of heart failure . The list can extend further if we include like associated renal dysfunction , hemoglobin concentration , etc .
Even though LV pump primarily determines the ultimate outcome in cardiac failure , it is unwise to blame the EF % for all the suffering . If only we realise this fact , one can take appropriate measures .
** Paradoxically modalities aimed to improve LVEF by positive inotropics has never been shown to improve the outcome .In-fact , there is more evidence for the contrary !