Arrhythmia
In some cases, heart disease can lead to an irregular rhythm or rate of the heartbeat known as an arrhythmia. While arrhythmias for the most part are harmless, there are some cases where they can be very severe and potentially fatal. The reason for this being that arrhythmias can affect the amount of blood the heart is able to pump. Arrhythmias can be categorized into three main groups. These groups are known as tachycardia, bradycardia, and irregular rhythm of the heart.
When a heart beats too fast it is known as tachycardia. This fast heart rate is specifically caused by abnormal electrical signals in the atria interfering with the hearts pacemaker, resulting in a faster heart rate. By increasing the beats per minute of the heart, it can reduce the amount of blood that fills the ventricles per beat. This can lower the overall amount blood pumped by the heart per minute. Tachycardia doesn’t show symptoms a lot of the time, but has been known in cases to cause dizziness, lightheadedness, chest pain and shortness of breath. In some very severe cases tachycardia can lead to unconsciousness or even a heart attack. A heartbeat slower than normal is known as bradycardia. The causes for bradycardia include problems with the hearts natural pacemaker, problems with conduction pathways in the heart, metabolic problems, and damage to the heart from a heart attack or heart disease. A slower heart rate lowers the number of beats per minute, which in turn lowers the amount of blood pumped by the heart per minute. Bradycardia has symptoms similar to tachycardia. These include dizziness, fatigue, lightheadedness, fainting, and cardiac arrest. In addition, severe bradycardia can lead to complications such as high blood pressure and even heart failure. The last group of arrhythmias is an irregular rhythm of the heartbeat. This group of arrhythmias include atrial fibrillation, ventricular fibrillation, premature contraction, conduction disorders, and more. If you want to find out more about these less severe causes of irregular heartbeat, you can find more information here. The two most serious cases of irregular heartbeat are atrial and ventricular fibrillation. Ventricular fibrillation is the quivering of the lower chambers of the heart that are used to pump blood out of the heart. When these quiver, the heart is unable to pump any blood, which causes cardiac arrest. Atrial fibrillation, on the other hand, is the quivering of the upper two regions of the heart that move blood into the ventricles. The main worry when dealing with atrial fibrillation is the increased risk of stroke. When the atria quiver as opposed to a regular contraction, it causes some blood to remain stagnant in the chamber. This allows a blood clot to form. If this clot gets pumps out of the heart and moves up into the brain, a stroke will occur. Because of this, many people with atrial fibrillation are put on blood thinners. There are many factors that affect the chances of developing an arrhythmia. These include levels of anxiety, alcohol consumption, caffeine consumption, and the presence of heart disease. It is important to try and limit alcohol and caffeine in your diet, reduce stress levels as much as possible, and take preventative measures against heart disease that you can find here. |
Below are animations that depict the heartbeats of a normal heart and hearts with different types of arrythmia. Alongside them are electrocardiographs that show the speed and rhythm of the heartbeat compared to a normal heartbeat.
Normal Heartbeat
Tachycardia
Bradycardia
Atrial Fibrillation
Ventricular Fibrillation
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American Heart Association. (2014, October 23). About arrhythmia. Retrieved October 16, 2016, from
http://www.heart.org/HEARTORG/Conditions/Arrhythmia/AboutArrhythmia/
About-Arrhythmia_UCM_002010_Article.jsp#.WAQEa-ArKhc
American Heart Association. (2014, October 23). Arrhythmias [Video file]. Retrieved from
http://watchlearnlive.heart.org/CVML_Player.php?moduleSelect=arrhyt
National Institutes of Health. (2011, July 1). What is an arrhythmia? Retrieved October 16, 2016,
from https://www.nhlbi.nih.gov/health/health-topics/topics/arr
http://www.heart.org/HEARTORG/Conditions/Arrhythmia/AboutArrhythmia/
About-Arrhythmia_UCM_002010_Article.jsp#.WAQEa-ArKhc
American Heart Association. (2014, October 23). Arrhythmias [Video file]. Retrieved from
http://watchlearnlive.heart.org/CVML_Player.php?moduleSelect=arrhyt
National Institutes of Health. (2011, July 1). What is an arrhythmia? Retrieved October 16, 2016,
from https://www.nhlbi.nih.gov/health/health-topics/topics/arr