How to Read Blood Presure & Heart Monitor at Hospital Bedside

On the printout, one large box equals .2 seconds.

Two common readings taken from patients at a hospital are heart rate and blood pressure. Loved ones may want to understand what's going on with the electrocardiogram, which monitors the heart, and the blood pressure readings they see. In order to do so, you need to understand what each wave of the electrocardiogram means, as well as the ranges of systolic and diastolic blood pressure. However, it takes a medical professional to properly interpret the data and make a diagnosis.

How to Read an Electrocardiogram

Step 1

Locate the flat or wavy line between the peaks. This is the P wave. It ends at the first rise or dip of the beat. P waves measure the depolarization of the atria, which means a heart muscle contraction, according to "Elementary ECG," published by the Laboratory of Nonlinear Systems. The time from the start of the P to the first Q or R wave should be between .12 and two seconds.

Step 2

Locate the first dip or spike of the heartbeat. If it's a dip, this is a Q wave, which is a downstroke. If it's a spike, this is an R wave, which is an upward deflection. Q waves can be a sign of a heart attack, or they can be normal. Only a doctor can make the determination.

Step 3

Check for a downward stroke below the P line after an R wave. If present, this is an S wave. The entire readout of these three waves is called the QRS complex, and it should last .08 to .12 seconds in a healthy individual.

Step 4

Locate the flat or wavy line after the QRS complex. This is the T wave, and it measures ventricular repolarization, which is the relaxing of the heart muscle.

How to Read Blood Pressure

Step 1

Locate the top number of the two numbers. This is the systolic blood pressure, which represents pressure within the heart during a beat. A normal systolic pressure should be between 90 and 120.

Step 2

Locate the bottom number of the two numbers. This is the diastolic blood pressure, or the pressure between heartbeats. A normal diastolic pressure should be between 60 and 80.

Step 3

Use the first number as the systolic pressure and the second number as the diastolic pressure if the reading is taken using a blood pressure cuff instead of a machine.


Use these measurements as a general guide, but leave diagnosis up to a medical professional.

Is This an Emergency?

If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911. If you think you may have COVID-19, use the CDC’s Coronavirus Self-Checker before leaving the house.