Hi can you explain the difference between heart rate and rhythm? I'm studying atrial fibrillation and flutter and I can't understand the difference between the two...
Wow! That is a fantastic question!
To start, heart rate means how fast the heart is beating. How many “beats per minute.” The easiest way to measure the rate would be putting your fingers on a patient’s pulse. This can get tricky sometimes because the atrium(top) can beat, contract or pump at a different rate than the ventricles(bottom). The pulse you feel in the wrist corresponds to the ventricular contractions. Looking at an electrocardiogram, or ECG/EKG, you can measure the beats per minute by looking at the number of PQRST complexes.
Now the rhythm corresponds to whether each P wave is followed by a QRS wave. Do the atrium and ventricles contract in succession? There are many variations to this and we call those arrhythmias. Each P wave being followed by a QRS wave is called Normal Sinus Rhythm. If there are no discernible P waves, meaning the atrium is not properly contracting, this is called Atrial Fibrillation because the atrium is fibrillating but not fully contracting.
During flutter the atria are contracting, but very very fast. So on the ECG you will see P waves. But not every P wave is followed by a QRS complex. Sometimes you see 2, 3 or 4 P waves prior to each QRS complex. It takes multiple atrial contractions for 1 ventricular contraction. It is called a “saw-toothed” pattern.