EKG Rhythms
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Cheat Sheet

What’s Included in the EKG Cheat Sheet?

Simplify your learning process with our electrocardiogram (EKG) interpretation cheat sheet.

Here’s what you’ll find inside:

  • List of nine EKG strips
  • Visuals for each rhythm.

Check Out Our EKG Rhythms Free Video Resource

Enhance your learning with our EKG rhythms video.

This animated video complements our cheat sheet with EKG strips by providing a visual and auditory learning experience. Learn about each rhythm, watch demonstrations, and listen to expert explanations to solidify your understanding.

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EKG Interpretation

Understanding EKG interpretations is crucial for nursing students.

Below, we’ve highlighted the key rhythms nurses encounter.

Normal Sinus Rhythm

Normal Sinus Rythm EKG (ECG)

Normal sinus rhythm is the baseline rhythm for all EKGs. It’s important for maintaining adequate blood flow and oxygenation.

Normal Sinus Rhythm Characteristics

  • Rate: 60-100 beats per minute (BPM)
  • Rhythm: Regular
  • P Wave: Normal
  • PR Interval: Normal
  • QRS: Normal

Normal Sinus Rhythm Causes

Normal sinus rhythm is the usual rhythm of a healthy heart.

Adequate oxygen supply to the heart is essential for maintaining normal sinus rhythm. Any conditions that decrease oxygen levels, such as respiratory distress or anemia, can disrupt normal sinus rhythm.


Bradycardia Rythm EKG (ECG)

Bradycardia is a slower-than-normal heart rate. It can prevent the heart from pumping enough oxygen-rich blood.

Bradycardia Characteristics

  • Rate: Less than 60 BPM
  • Rhythm: Regular
  • P Wave: Normal
  • PR Interval: Normal
  • QRS: Normal

Bradycardia Causes

Potential causes of bradycardia include medications (beta-blockers) and the vagal maneuver (bearing down).

Ventricular Fibrillation (V-Fib)

V Fib Rythm EKG (ECG)

V-fib is the deadliest rhythm. It’s a chaotic pattern of electrical activity in the ventricles in which electrical impulses arise from many foci.

V-Fib Characteristics

  • Rate: Unknown or indistinguishable
  • Rhythm: Chaotic waveform and rhythm
  • P Wave: None because the atria aren’t contracting
  • PR Interval: None because the atria aren’t contracting
  • QRS: None because the ventricles aren’t fully contracting

V-Fib Causes

V-fib can occur due to cardiac injury (heart attack, valvular disease), electrical imbalances (acid-base, electrolyte imbalances, electrical shock, unsuccessfully treated ventricular tachycardia), and medication toxicity.

Ventricular Tachycardia (V-Tach)

Ventricular Tachycardia (V-Tach) Rythm EKG (ECG)

V-tach is an extremely rapid heart rhythm originating from the ventricles when the sinoatrial (SA) node and the atrioventricular (AV) node fail to produce an impulse. In this scenario, the ventricles take over the responsibility of pacing the heart.

V-Tach Characteristics

  • Rate: 100-250 BPM
  • Rhythm: Regularly spaced and even like tombstones
  • P Wave: None
  • PR Interval: None
  • QRS: Wide and even

V-Tach Causes

Potential causes include cardiac injury (history of heart attack), electrolyte imbalances, medication toxicity, stimulants (caffeine, methamphetamines) or stress.

Atrial Fibrillation (A-Fib)

A Fib Rythm EKG (ECG)

A-fib is a common arrhythmia that causes the heart to beat rapidly and irregularly.

It occurs when the heart’s electrical signals are disorganized, causing the atria (upper chambers) to quiver instead of contracting properly.

A-Fib Characteristics

  • Rate: Usually over 100 BPM
  • Rhythm: Irregular
  • P Wave: None because the atria aren’t contracting
  • PR Interval: None because the atria aren’t contracting
  • QRS: Normal

A-Fib Causes

Potential causes include alcohol (holiday heart), hyperthyroidism, open heart surgery, and pulmonary hypertension.

Atrial Flutter (A-Flutter)

Atrial Flutter Rythm EKG (ECG)

A-flutter is similar to A-fib. But the heart’s electrical signals spread through the atria in a fast but regular rhythm instead of irregular.

A-Flutter Characteristics

  • Rate: 75-150 BPM
  • Rhythm: Usually regular
  • P Wave: No P wave
  • PR Interval: None
  • QRS: Usually normal

A-Flutter Causes

Causes of A-flutter include heart disease, pulmonary embolism, or chronic obstructive pulmonary disease (COPD). Certain medications can also trigger it.

Supraventricular Tachycardia (SVT)

SVT is an abnormal heart rhythm.

It involves episodes of rapid heart rate that begin in a part of the heart above the ventricles.

SVT Characteristics

  • Rate: 150-250 BPM
  • Rhythm: Regular
  • P Wave: Buried in the preceding T wave
  • PR Interval: Usually not measurable
  • QRS: Normal

SVT Causes

Common causes are heart failure, COPD, stimulants (alcohol, caffeine, cigarettes, exercise), sepsis (infection of the blood), and stress (anxiety).

Torsades de Pointes

Torsades de pointes translates from French to “twisting of the points.”

It’s a life-threatening heart rhythm disorder that causes the heart’s lower chambers to beat rapidly and out of sync.

Torsades de Pointes Characteristics

  • Rate: 200-250 BPM
  • Rhythm: Irregular
  • P Wave: None
  • PR Interval: None
  • QRS: Wide

Torsades de Pointes Causes

Causes of Torsades de Pointes include cardiac injury (heart attack), electrolyte imbalances (hypokalemia, hypomagnesemia, low magnesium), stimulants (alcohol, caffeine, cigarettes), and unsuccessfully treated V-tach.

Asystole (Flatline)

Asystole is a cardiac arrest rhythm where the heart doesn’t produce electrical activity. As a result, the heart stops beating, and the EKG monitor shows a total standstill.

Asystole Characteristics

  • Rate: N/A
  • Rhythm: N/A
  • P Wave: N/A
  • PR Interval: N/A
  • QRS Duration: N/A

Asystole Causes

Causes of asystole include trauma or lethal cardiac rhythms like V-tach, V-fib, and ST-segment elevation myocardial infarction (STEMI).

This concludes our review of the nine most common EKG rhythms. Remember that each rhythm has unique characteristics and requires specific treatment.

Understanding their differences is crucial for providing prompt and appropriate care in a medical emergency.

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