Heart Rhythms

The heart can go into different heart rhythms due to problems with the electric pathway which originates in the sinus none (SA node).


The normal heart rate is called sinus rhythm. Some rhythms are regular but they are abnormal because the heart rate is either below 60 bpm or above 100 bpm. Irregular heart beats are called arrhythmias and some of them can be lethal if not treated immediately.

Normal Sinus Rhythm
Regular Heart Rhythm


Sinus Rhythm Graphic
Morphology of a heart beat


Calculating the heart rate
The easiest method of calculating the heart rate is to divide 1500 by the number of small boxes between the R waves. On the rhythm above, there are 19 small boxes. If we divide 1500 by 19, we get 78. The heart rate is 78 beats per minute.

You can also divide 300 by the number of large boxes between the R waves. There are 3.8 large boxes. The heart rate will still be 78 beats per minute.



Here is a list of some of the abnormal rhythms:

  • Sinus bradycardia
  • Sinus Tachycardia
  • Atrial Fibrillation - this heart arrhythmia is very common in the United States. The top chambers of the heart are beating in a disorganized manner. This is because the electrical impulses spread to the atria instead of traveling down to the ventricles.
  • Atrial flutter
  • Ventricular tachycardia
  • Ventricular fibrillation
  • Torsades de pointes
  • First degree heart block
  • Second degree heart block
  • Second degree heart block type 2
  • Third degree heart block or complete heart block
  • Asystole

    Cardiac rhythms are printed on EKG graph paper in order to measure and to determine the type of rhythm with more accuracy.

    We will discuss some of these rhythms briefly just so you can have an idea about what the differences are. The idea is to make it very simple making it easier to understand.



    Heart Attacks are the number one killer in America. Make it your goal in life to prevent a heart attack in the future. Start paying attention to your daily habits such as diet, exercise, stress, smoking, alcohol, and drugs. Practicing good habits on an ongoing basis will help you lead a future healthy life.


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