Fast & Easy ECGs – A Self-Paced Learning Program 3 Heart Rate Fast & Easy ECGs – A Self-Paced Learning Program Q I A

Dysrhythmias Irregularities in heart rate or rhythm Some are of little significance whereas others are life threatening Instructional point: Emphasize that whenever dysrhythmias are present the patient must be assessed. Part of this assessment should include checking the patient’s pulse. I

ECG Analysis Five Step Process is a logical and systematic process for analyzing ECG tracings Instructional point: The Five Step Process is one approach for analyzing ECG tracings that can be easily remembered and applied. Successful analysis of ECGs is based on learning the characteristics of each normal and abnormal ECG then comparing what you see on the ECG tracing to those characteristics. I

Normal Sinus Rhythm Characteristics Rate: 60 - 100 BPM Rhythm: Regular P waves: Upright and round, one preceding each QRS complex QRS complexes: Narrow, 0.06 - 0.12 seconds in duration PR Interval: 0.12 - 0.20 seconds in duration T waves: Upright and slightly asymmetrical Instructional point: Normal sinus is what we compare all other rhythms against. I

Determining Heart Rate First step in analyzing an ECG rhythm Begin by quickly checking ECG monitor or tracing to see if rate is slow, normal or fast Answer: slow Instructional points: A quick assessment of the heart rate can be done by looking at the space between QRS complexes. More space indicates a slow heart rate while less space indicates a faster heart rate. Heart rate x stroke volume = cardiac output. A very slow or fast heart rate can cause cardiac output to decrease by lowering the rate or decreasing the stroke volume. Compromised cardiac output requires immediate treatment. I

Calculating Heart Rate Several methods can be used including: 6-Second Interval x 10 Method 300, 150, 100, 75, 60, 50 Method 1500 Method Rate Calculator Instructional point: The P waves can be counted to determine the atrial rate and the QRS complexes counted to determine the ventricular rate. I

6-Second Interval x 10 Method Quick and easy and does not require tools or devices Not as accurate as other methods Multiply by 10 the number of QRS complexes found in a six second portion of ECG tracing Instructional points: Typically there are markings on the top and/or bottom indicating each 3-second block of time. Two of these successive (adjacent to each other) blocks of time equal six seconds. When you multiply that amount of time by ten, it represents 60 seconds or one minute. With very irregular rhythms try using a 12 second area of the tracing, count the number of QRS complexes (and/or P waves) multiply them by 5 (instead of 10). I

Practice Makes Perfect Determine the heart rate using the 6-second interval x 10 method Answer: 70 beats per minute. I

Practice Makes Perfect Determine the heart rate using the 6-second interval x 10 method Answer: 140 beats per minute. I

Practice Makes Perfect Determine the heart rate using the 6-second interval x 10 method Answer: 50 beats per minute. I

300, 150, 100, 75, 60, 50 Method Quick, fairly accurate, requires no special tools, or calculations Cannot be used with irregular rhythms Find an R wave located on a bold line. Then find the next consecutive R wave. Bold line it falls on (or is closest to) represents the heart rate.

300, 150, 100, 75, 60, 50 Method If the second R wave does not fall on a bold line the heart rate is approximated Example: if it falls between the 4th and 5th bold line the heart rate is between 60 and 75 BPM

300, 150, 100, 75, 60, 50 Method If the second R wave falls in between two bold lines the heart rate can be more precisely determined using the identified values for each thin line Instructional point: It may be hard for the student to remember these values; for this reason the student may want to carry a card with those numbers listed. I

Practice Makes Perfect Determine the heart rate using the 300, 150, 100, 75, 60, 50 method Answer: 125 beats per minute I

Practice Makes Perfect Determine the heart rate using the 300, 150, 100, 75, 60, 50 method Answer: 75 beats per minute I

Practice Makes Perfect Determine the heart rate using the 300, 150, 100, 75, 60, 50 method Answer: 41 beats per minute I

1500 Method Most accurate and requires no special tools but math calculation must be done to determine heart rate Cannot be used with irregular rhythms Count the number of small squares between two consecutive R waves and divide 1500 by that number Instructional point: An example is if you have 20 small squares (which is equal to four large boxes) the heart rate is 75 beats per minute (we arrive at this by dividing 1500 by 20). This can be used to calculate the atrial rate as well by measuring the number of small squares between the peaks of two consecutive P waves. I

Practice Makes Perfect Determine the heart rate using the 1500 method Answer: 41 beats per minute I

Practice Makes Perfect Determine the heart rate using the 1500 method Answer: 94 beats per minute I

Practice Makes Perfect Determine the heart rate using the 1500 method Answer: 59 beats per minute I

Rate Calculators Easy to use but not always available Ineffective on irregular rhythms where a consistent baseline is not present Position the “start mark” on an R wave Then find the next consecutive R wave – where it lines up is the approximate heart rate

Heart Rates Average adult has a heart rate of 60-100 BPM Heart rate < 60 BPM called bradycardia Heart rate > 100 BPM called tachycardia Instructional point: Both bradycardia and tachycardia can occur for many reasons. I

Sinus Bradycardia Slow rate that arises from SA node May or may not have an adverse affect on cardiac output In extreme cases it can lead to severe reductions in cardiac output and eventually deteriorate into asystole

Sinus Arrest Transient failure of SA node to initiate a heart beat Can lead to a slow heart rate Instructional point: SA node will initiate an impulse or an escape pacemaker will take over and initiate the heart beat. I

AV Heart Blocks Blockage of the impulse traveling through the AV node can cause a slow heart rate 2nd – degree AV heart block One type of blockage is called 2nd degree AV heart block. Not all the sinus beats are conducted through to the ventricles. Results in more P waves than QRS complexes and a slower ventricular rate.

AV Heart Blocks 3rd - degree AV heart block occurs with complete blockage of AV node Instructional point: The atria are stimulated to contract by an impulse that originates from the SA node while the ventricles they are stimulated to contract by an escape pacemaker. I

Rapid Atrial Rates With Slow Ventricular Rates Because of the rapid rate not all atrial impulses are conducted through to the ventricles A slower than normal ventricular rate can result if the number of atrial impulses reaching the ventricles falls to less than normal

Atrial Flutter Instructional point: This dysrhythmia is called atrial flutter with a slow ventricular response. I

Atrial Fibrillation Instructional point: In atrial fibrillation the atria fire and bombard the AV node more than 350 times per minute. Not all atrial impulses are conducted through to the ventricles. If the number of atrial impulses reaching the ventricles falls to less than normal it results in a slower than normal ventricular rate. Called atrial fibrillation with a slow ventricular response. Irregularly irregular rhythm is ALWAYS AF!!!!!!! I

Sinus Tachycardia Fast rate, > 100 BPM, arises from the SA node

Tachycardia From an Ectopic Pacemaker Results from rapid depolarization that overrides the SA node Supraventricular tachycardia is term used for ectopic tachycardia arising from above the ventricles Atrial tachycardia Generally 150-250 BPM Junctional tachycardia Generally 100-180 BPM Instructional point: Supraventricular tachycardia is a term we can use if the origin of narrow QRS complex tachycardia cannot be determined. The reason is that in some fast rhythms the P waves are hidden in the T wave of the preceding beat. Can be either atrial or junctional tachycardia. I

Tachycardia From an Ectopic Site

Tachycardia From an Ectopic Pacemaker Ventricular tachycardia arises in the ventricles and has a rate of 150-250 BPM

Rapid Atrial Rates With Fast Ventricular Rates In addition to having either a normal or slow ventricular rate in atria flutter the ventricular rate can also be fast Instructional point: Called atrial flutter with a fast ventricular response. I

Rapid Atrial Rates With Fast Ventricular Rates In addition to having either a normal or slow ventricular rate in atria fibrillation the ventricular rate can also be fast Instructional point: Called atrial fibrillation with a fast ventricular response. I

Summary Approach each ECG tracing analysis in a logical and systematic manner. Some dysrhythmias are of no problem to the patient whereas others are life threatening. Five steps to analyzing an ECG rhythm are determining the: Heart rate Regularity Presence of and characteristics of P waves Presence of and characteristics of QRS complexes Presence of and characteristics of the PR intervals Instructional point: If a dysrhythmia is present, compare your finding with your assessment of the patient. I

Summary To determine the heart rate first check to see if the rate is slow, normal or fast. The 6-second interval x 10 method multiplies by 10 the number of QRS complexes found in a 6-second portion of the ECG tracing. The 300, 150, 100, 75, 60, 50 method involves locating an R wave on a bold line on the ECG paper, then finding the next consecutive R wave and using the 300, 150, 100, 75, 60, 50 values for subsequent bold lines to determine the rate. To use the 1500 method count the number of small squares between two consecutive R waves and divide 1500 by that number. Instructional point: Remind the students that the QRS complexes are counted to determine the ventricular rate and the P waves are counted to determine the atrial rate. I

Summary A heart rate less than 60 beats per minute is called bradycardia. Slow heart rates are seen with sinus bradycardia, junctional escape rhythm, idioventricular rhythm, AV heart block and atrial flutter or fibrillation with slow ventricular response. A heart rate greater than 100 beats per minute is called tachycardia. Fast heart rates are seen with sinus tachycardia, atrial tachycardia, junctional tachycardia, ventricular tachycardia and atrial flutter or fibrillation with rapid ventricular response. Instructional point: Remind the students that both extremely slow and fast heart rates can result in decreased cardiac output. I