Atrial fibrillation press?
Answer:
The impulse surrounded by question is generate normally by the sinoatrial (SA) node, a group of cell positioned on the wall of the right atrium responsible for the normal cardiac cycle. This cluster of cell receives input from the brain through the sympathetic and parasympathetic systems (Neurohormonal and vagus nerves) to opt how fast they should fire.
The "impulse" is a complex conduct potential of sodium, potassium, and calcium ions all entering and exiting the cell in a controlled fad to signal the muscle cells to contract and relax. [See sources for more detailed answer]
In atrial fibrillation, the regular impulse produced by the SA node to provide rhythmic contraction of the heart are overwhelmed by the rapid unpredictably generated electrical discharges produced by larger areas of atrial tissue. Stretching of the right atrium lead to atrial fibrillation many times, but in attendance are a lot of cause.
So A-fib in essence is disorganized electrical impulse that is interpreted by the atria as a signal to contract. These hundreds of signals trigger a fibrillating of the atria beside no real potent contraction. Blood however still travels through to the ventricles, but the flow is stagnant in some areas, which is why AF increases the odds of clot and stroke.
Fortunately, the heart as another node called the atrioventricular (AV) node. This node (usually) receive all atrial signals and act as a gatekeeper when delivery rapid singals. It have a property called "decremental conduction" which allows for a slight adjournment before transmitting signals to the ventricles to contract.
Sometimes though, frequent of those fast, irregular SA signals are transmitted through the AV node and we acquire "atrial fibrillation with fast ventricular response" or A-fib with RVR. This swift rate can lead to a lessening of blood pressure since the heart isn't pumping as efficiently. Treatment surrounded by this case is directed toward slowing conduction through the AV node using "AV-nodal blockers" close to beta-blockers (labetolol), calcium channel blockers (diltiazem), and digoxin. In cases of life-threatening low blood pressure, shocking the heart is successful at reestablishing a good rhythm.
A-fib beside RVR usually has a rate of 120-160. You'll awareness that this is still slower than the 300-400 that the atria are firing. This is because of the AV node's ability to obstruction many of the atrial impulse before firing, but it can usually do even a better charge at slowing the ventricular impulse than this.
In a commonplace fast heart rate, close to when exercising. The brain tells the SA node to increase it's quirk frequency. So the SA node fires faster, but still regular, impulses that are conducted through the AV node. This is sinus tachycardia and is conventional.