For example, a certain maize variety grown in a cool climate will need less water per day than the same maize variety grown in a hotter climate. It is therefore useful to take a certain standard crop or reference crop and determine how much water this crop needs per day in the various climatic regions.
An implantable cardioverter defibrillator (ICD) looks very similar to a pacemaker, except that it is slightly larger. It has a generator, one or more leads, and an electrode for each lead. These components work very much like a pacemaker.
In addition, the heart failure patient may or may not need this type of pacemaker to treat slow heart rhythms and may or may not need an internal defibrillator (implantable cardioverter defibrillator, or ICD), which is designed to treat people at risk for sudden cardiac death or cardiac arrests.