Cardiac contractility modulation for heart failure, such as pacemaker therapy or implantable cardioverter defibrillators (ICD), Cardiac contractility modulation does not affect the cardiac rhythm directly. Rather, the aim is to enhance the heart’s natural contraction (the native cardiac contractility) sustainably over long periods of time. Furthermore, unlike most interventions that increase cardiac contractility, the Cardiac contractility modulation is not associated with an unfavorable increase in oxygen demand by the heart (measured in terms of Myocardial Oxygen Consumption or MVO). This may be explained by the beneficial effect the therapy has in improving cardiac efficiency. A meta-analysis in 2014 and an overview of device-based
Cardiac physiology heart with each contraction. To calculate ejection fraction, SV is divided by EDV. Despite the name, the ejection fraction is normally expressed as a percentage. Ejection fractions range from approximately 55–70 percent, with a mean of 58 percent. Many of the factors that regulate the heart rate also affect cardiac function by altering the stroke volume. While a number of variables are involved, stroke volume is dependent upon the difference between end diastolic volume and end systolic volume. The three primary factors involved are preload, afterload and contractility. Preload is another way of expressing EDV. Therefore, the greater the EDV,