Supraventricular tachycardia - AV nodal reentry. Wolff-Parkinson-White syndrome. Return to Technical Skills Home. PR interval: Normally between 0. Every time your heart beats, it sends a pulse wave throughout your arteries. Apple Watch measures those pulse waves at the wrist, but anywhere on the skin with good blood perfusion—e. The drawback of PPG is that it only measures a pulse wave. Nevertheless, with a longer sample time—say, ten minutes of data rather than 30 seconds—PPG data is sometimes clear enough to distinguish the rhythm visually.
For more ambiguous cases, techniques like deep learning can help us separate the signal from the noise more on that in future posts. Atrial fibrillation is the most common abnormal heart rhythm, responsible for about a quarter of all strokes. In atrial fibrillation, electrical activity within the atria becomes chaotic, which causes the ventricles to contract at seemingly-random intervals. The good news is an optical heart rate sensor can detect atrial fibrillation.
Abnormal heart rhythms can also be exceptionally regular. In atrial flutter, an electrical loop within the atria causes them to contract at around beats per minute. The AV node acts as a rate limiter, transmitting every 2nd, 3rd, 4th, or 5th electrical impulse—, , , or conduction—so that the heart rate is near , , 75, or 60 bpm:.
Medicine Flashcard Collection. A collection of surgery revision notes covering key surgical topics. Aortic Dissection. Surgery Flashcard Collection. Anatomical Planes.
Anatomy Flashcard Collection. The Inguinal Canal. A man with penile swelling. A man with blood in his urine. PSA Question Bank. Medical Student Finals Question Bank. ABG Quiz. Share Tweet. Last updated: November 12, Suggest an improvement. You don't need to tell us which article this feedback relates to, as we automatically capture that information for you. This allows us to get in touch for more details if required. Ideally, an EKG can measure any potential disruptions.
These include:. This can signal that the heart is working harder than normal to pump blood. Electrolyte imbalances : Electrolytes are electricity-conducting particles in the body that help keep the heart muscle beating in rhythm. Potassium , calcium , and magnesium are electrolytes. If your electrolytes are imbalanced, you may have an abnormal EKG reading. Heart attack or ischemia: During a heart attack, blood flow in the heart is affected and heart tissue can begin to lose oxygen and die.
This tissue will not conduct electricity as well, which can cause an abnormal EKG. Ischemia, or lack of blood flow, may also cause an abnormal EKG. Heart rate abnormalities: A typical human heart rate is between 60 and beats per minute bpm. An EKG can determine if the heart is beating too fast or too slow. Heart rhythm abnormalities: A heart typically beats in a steady rhythm. An EKG can reveal if the heart is beating out of rhythm or sequence. Examples of medications that affect heart rhythm include beta-blockers , sodium channel blockers, and calcium channel blockers.
Learn more about arrhythmia drugs. Several symptoms can indicate that you may need an EKG to determine if your heart is functioning normally.
0コメント