EKG Interpretation

Electrocardiogram

Records cardiac electrical activity.

• Same heartbeat, different view.

Depolarization

The electrical impulse that activates the heart to contract.

Repolarization

The heart muscle relaxes.

P-Wave

Atrial depolarization (atria contracting)

PR Interval

Related to the rate of cardiac impulse transmitted from the AV node. The time from when the P starts until the QRS starts.

QRS Complex

Ventricular depolarization (ventricle contracting)

ST Segment

Follows ventricular depolarization and occurs prior to the start of ventricular repolarization.

T Wave

Ventricular repolarization is occurring.

QT Interval

The time for ventricular repolarization to complete. (can be effected by certain medications)

EKG Strips - 5 Large Boxes

Equals 1 Second

EKG Strips - 15 Large Boxes

Equals 3 Seconds

EKG Strips - 30 Large Boxes

Equals 6 Seconds

EKG Strips - 1 mm (Small Boxes)

Equals 0.04 Seconds

EKG Strips - 5 mm (Small Boxes)

Equals 0.2 Seconds

7 QRS Complexes in 6 Sec

7 X 10 = 70 bpm

Step 1 for ECG Analysis

Calculate heart rate.

Count R spikes for 6 seconds and multiply by 10.

Step 2 for ECG Analysis

Determine if the heart rhythm is regular.

Are the Rs evenly spaced?

Step 3 for ECG Analysis

Assess for P waves.

Is it there and is it married to the QRS?

Step 4 for ECG Analysis

Measure the PR interval.

Normal: 0.12-0.2 seconds

Step 5 for ECG Analysis

Measure the duration of the QRS complex.

Is it there? Is it wide?

Normal: 0.08-0.12 seconds

Sinus Bradycardia

BPM < 60

Asymptomatic or symptomatic

• Fatigue

• Increased SOB

• Dizziness

Fall precautions for symptomatic bradycardia!!

Unstable clients

• IV atropine 1 mg repeat every 3-5 minutes not to exceed a total of 3 mg.

• Monitor for changes in heart rate

Temporary transcutaneous pacemaker if client continues to remain unstable and symptomatic

Sinus Tachycardia

BPM > 100

• Palpitations

• Dizziness

• Lightheadedness

• Elevated temperature

• Chest pain

• Difficulty breathing

If symptomatic: decrease physical intensity or activities. Change position slowly!

Administer Medications as ordered

• Adenosine

• Betablockers (metoprolol)

Catheter Ablation

• Performed to destroy the abnormally excited cardiac cells responsible for increased heart rate

Premature Ventricular Contractions (PVCs)

Bigeminy  & Trigeminy

• Bigeminy — every other beat is a PVC

• Trigeminy — every third beat is a PVC;

ECG: Wide, bizarre QRS not preceded by a P wave; Missing p-wave where the PVC occurs

Symptoms:

• Palpitations

• Lightheadedness

• Chest pain

• Shortness of breath

Potential causes for PVCs:

• Potassium

• Magnesium

• Thyroid levels

PVCs can be normal and may occur often in healthy clients.

Client teaching to minimize or prevent PVCs

• Smoking cessation

• Minimize alcohol

• Eliminate illicit drug use

• Reduce caffeine intake

Premature Atrial Contractions

• The P wave associated with PAC may be hidden or unidentifiable

•  The PR interval may be shortened less than 0.12 or unmeasurable

• Usually have no manifestations but may feel fluttering in the chest

• PACs are frequently asymptomatic & do not pose a safety risk to the client.

 

First-Degree Heart Block

Regular rhythm with a wide PR interval

Contribute to first degree heart block

• Diets high in sodium, cholesterol or triglycerides

Lifestyle modification

• Avoid smoking, alcohol consumption and eat a healthy low-cholesterol diet

• Avoid excessive fatigue

Atrial Fibrillation

NOT A SHOCKABLE RHYTHM

Confirm diagnosis: a-fib is an ECG.

P waves replaced by atrial activities between QRS complexes

HR is fast, irregular, and weak.

Rate can be (60 to 100) or increased (100 to 200)

Asymptomatic or Symptomatic

• Irregular pulse

• Heart palpitations

• Increased heart rate

• Chest discomfort

• Shortness of breath (At rest or with activity)

• Fatigue

• Dizziness/Lightheadedness/Syncope

Safety:

• Client at risk for stroke & Risk for spontaneous bleeding

Education:

• Report manifestations

• Take medications as prescribed

• Bleeding precautions

• Healthy lifestyle modifications

• Avoid stimulants

• Avoid herbal supplements

Treatment - Rhythm control

• Electro cardioversion

• Catheter ablation

• Anticoagulants

• Diet modification

Atrial Flutter

Often regular and looks like a saw

• Lightheadedness

• Palpitations

• Hypotension

• Dizziness

• Chest discomfort

• Shortness of breath

Same for atrial flutter as it is for a-fib.

Supraventricular Tachycardia (SVT)

Can’t measure a PR interval

QRS is skinny

• Manifestations may present suddenly

• Dizziness

• Lightheadedness

• Syncopal episodes

• Hypotension

• Shortness of breath

• Palpitations

• Increased risk of falls

Vagal maneuvers

IV adenosine 6 mg IV over 1 to 3 seconds then flush with 20 mL NS

• If no change give a repeat dose of 12 mg followed by 20 mL NS

• Adenosine will the heart rate: have a defibrillator on hand