In ventricular fibrillation, the ventricles twitch randomly instead of beating. This condition causes death within minutes if no
t rapidly treated. In a similar condition, atrial fibrillation, atria twitch randomly instead of beating. Although atrial fibrillation can increase the risk of other serious conditions, atrial fibrillation by itself is usually not life threatening. Explain why ventricle fibrillation is deadly but trail fibrillation rarely is. Include a description of blood flow through the heart.
Ventricular fibrillation a type of arrhythmia characterized by a very fast heart rate which causes no blood to reach vital organs causing cardiac arrest.While Atrial fibrillation is an atrial tachyarrhythmia characterized by the fact that the atria beat in an uncoordinated way at a very high rate that exceeds 350 beats per minute. As a result, the atria are no longer effective in pumping blood to the ventricles.
Explanation:
Under normal conditions the heart contracts rhythmically and synchronously. This contraction is the result of an electrical impulse that is generated in the atrium, reaches the ventricle and results in a heartbeat. In an arrhythmia there is an alteration of this mechanism that leads to the heart not contracting regularly, generating a rhythm disorder. The contraction of the ventricles pumps blood to the rest of the body. In ventricular fibrillation, the heart rhythm is very fast and chaotic (up to 300 beats per minute) and is characterized by not being able to provoke an efficient heart beat. Thus, the lack of contraction of the ventricles causes the blood to barely be pumped from the heart, producing a collapse of the cardiovascular system and cardiac arrest. Atrial fibrillation is characterized by disorganized and very rapid atrial activity (350-600 beats / min). This leads to an irregular ventricular response (150-200 beats / min) and an irregular pulse.During atrial fibrillation, the atrial contraction that helps fill the ventricles with blood is lost; this can significantly reduce cardiac output, particularly in patients with mitral stenosis, hypertension, or hypertrophic cardiomyopathy.It is associated with an increased risk of thromboembolism (formation of blood clots in the heart that can dislodge and go through the bloodstream until impacted on the a blood vessel, causing lack of irrigation in that area) and therefore stroke (cerebral thromboembolic accident).
The Magic number 7 (plus or minus two) provides evidence for the capacity of short term memory. Most adults can store between 5 and 9 items in their short-term memory. This idea was put forward by Miller (1956) and he called it the magic number 7.
