ekg

When the myocardium is deprived of oxygen,

--- it becomes ischemic and 'depressed ---.This results in ST depression-below the isoelectric line=the horizontal line starting before the "P" wave that imaginarily travels across the waveforms

QRS complex

--- to the end of the T wave. ---Normally, the QT interval is 0.36 to 0.44 seconds (9-11 boxes).

Determine EKG 1st step

---- Count the QRS complexes over a 6 second ---- Multiple by 10 to determine HR. so this is 7 x 10=70

QRS wave

----0.06 to 0.12 seconds ----is ventricular depolarization and contraction. --- If it is > than this, it is termed a Bundle Branch Block.

j point

----The point where the S and the T wave join is the J point and is important in diagnosing cardiac ischemia or injury.

P wave

---0.06-0.11 seconds --- atria are contracting, pumping blood into the ventricles.

PR

---0.12 to 0.20 seconds --interval indicates the transit time for the electrical signal to travel from the sinus node to the ventricles.

Determine EKG 2nd step

---Count the small boxes for R-R interval. --- Divide this number into 1500 to determine heart rate.

st depression

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Determining Rate and Rhythm

1. First ask yourself are there P waves? 2. What is the QRS width? 3. Is it a Regular rhythm? 4. Are P waves related to the QRS? 5. What is the Heart Rate

Calculating the Heart Rate

1. Rule of 300: If the rhythm is regular, the heart rate can be "estimated" by using the "Rule of 300". Count the number of large squares between two R waves and divide this number into 300. ( There are 300 boxes, or 1500 tiny boxes, in a one minute strip)

Calculating the Heart Rate

2. The Six-Second Method: Count the number of complete R waves within a period of 6 seconds and multiply that number by 10. This is the one minute heart rate. This method can be used when the rhythm is "regular or irregular".

Calculating the Heart Rate

3. The Three-Second Method: Count the number of complete QRS complexes in a period of three seconds and multiply that by twenty. This is the one minute heart rate. 4. The Block Method: Find a QRS complex that hits exactly on a vertical line.

PR

< 0.20 seconds or one big box. --- If measurement is longer than 0.20 seconds (or one big box) it is defined as a 1st Degree AV Block

Analyzing a Rhythm Strip Using the Eight Step Approach step Three: Evaluate P Waves

Are P waves present and uniform in appearance? Are P waves upright (positive) in Lead II? Do P waves appear regularly before each QRS complex or is there More than one P wave before a QRS complex? If irregular is there an associated beat?

Analyzing a Rhythm Strip Using the Eight Step Approach step Three Step Five Step Six: Evaluate T Wave

Are T waves present? Are T waves smooth and rounded? Do they have normal amplitude of 0.5 mV or less? Is the deflection the same as the preceding QRS? Is there a relationship between any ectopy to the T wave?

Analyzing a Rhythm Strip Using the Eight Step Approach Step Two: Determine the Rhythm

Determine if the ventricular rate is regular or irregular, measure the distance between two consecutive R-R intervals Use a point from one R wave to the same point on the next R wave. Then compare this with another R-R interval. If the atrial rate is regular, the R-R interval will measure the same. Is the rhythm regular? Basically regular? Regularly irregular? Irregularly irregular? -

Analyzing a Rhythm Strip Using the Eight Step Approach step Three Step Five: Evaluate the QRS complex

Do the QRS complexes occur uniformly and look the same throughout the strip? If the QRS measures .10 second or less it is considered narrow and is presumed to be supraventricular in origin.

EKG Strip

EKG Strip

EKG Strips

EKG Strips

Analyzing a Rhythm Strip Using the Eight Step Approach step Three: Step Four: Evaluate the P-R interval

If the P-R interval is less than 0.12 or more than 0.20 second, conduction follows an abnormal pathway or the electrical impulse was delayed at the AV node. The normal P-R interval is 0.12 to 0.20 second. Is the P-R interval consistent?

Analyzing a Rhythm Strip Using the Eight Step Approach step Three Step Five: Evaluate the QRS complex

If the QRS complex is greater than .12 second or more it is considered wide, and presumed to be ventricular in origin until proven otherwise. The QRS normally measures 0.04 to 0.10 seconds in duration. Determine if they are married to the P waves

Analyzing a Rhythm Strip Using the Eight Step Approach Step Eight: Evaluate other components

Is the ST segment elevated? Depressed? Sloping or scooped? Are U waves present? Prominent? Are there other (funny little beats) FLB's detected

Sinus Bradycardia

May be due to: a normal response to sleep or in well conditioned athlete, abnormal drops in rate could be caused by diminished blood flow to S-A node, vagal stimulation, hypothyroidism, increased intracranial pressure, or pharmacologic agents, such as digoxin, propranolol, quinidine, or procainamide. -

Sinus Tachycardia

May be the result of stress, exercise, pain, fever, pump failure, hyperthyroidism, drugs-caffeine, nitrates, atropine, epinephrine, and isoproterenol, nicotine

Analyzing a Rhythm Strip Using the Eight Step Approach

Step One: Determine the Rate: What is the atrial rate? To determine the atrial rate, measure the distance between P-P. What is the ventricular rate? To determine the ventricular rate, measure the distance between R-R. Note: The rate of a Normal Sinus Rhythm is 60-100 beats per minute

Analyzing a Rhythm Strip Using the Eight Step Approach step Step Seven: Evaluate the QT Interval

Step Seven: Evaluate the QT Interval Is the duration from 0.36 to 0.44 seconds?

Analyzing a Rhythm Strip Using the Eight Step Approach Step Two: Determine the Rhythm

Step Two: Determine the Rhythm Is the rhythm is regular or irregular? To determine if the atrial rate is regular or irregular, measure the distance between two consecutive P-P intervals. Use a point from one P wave to the same point on the next P wave. Then compare this with another P-P interval. If the atrial rate is regular, the P-P interval will measure the same.

relationship of ecg to cardiac anatomy

The P wave represents atrial activation; the PR interval is the time from onset of atrial activation to onset of ventricular activation. The QRS complex represents ventricular activation; the QRS duration is the duration of ventricular activation. The ST-T wave represents ventricular repolarization. The QT interval is the duration of ventricular activation and recovery. The U wave probably represents "after depolarization" in the ventricles.

U-wave

is a small upright, rounded bump. When observed, it follows the T-wave.