Natural selection, which includes sexual selection, is the fact that some traits make it more likely for an organism to survive and reproduce. Population genetics describes natural selection by defining fitness as a propensity or probability of survival and reproduction in a particular environment. The fitness is normally given by the symbol w=1-s where s is the selection coefficient.
Atrial fibrillation with RVR (Rapid Ventricular Response) is a heart condition caused by irregular electrical activity that results in irregular contractions of the heart walls and its chambers. The heart (atrium), shakes with a rapid tremulous movement or makes fine irregular twitching movements, generally referred to as fibrillating.
Atrial Fibrillation: Heart Symptoms, Diagnosis & Treatment for AFib. Atrial fibrillation(AFib) is the most common type of abnormal heart rhythm. Atrial fibrillation or AF can lead to serious heart complications like stroke. Risks associated with AFib are related to heart rhythm changes. Treating atrial fibrillation addresses these changes in heartbeat.