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Introduction ⬇

On the line

Identifying idioventricular rhythm

This rhythm strip illustrates idioventricular rhythm. Look for these distinguishing characteristics:

Rhythm

  • Regular

Rate

  • Unable to determine atrial rate; ventricular rate of 35 beats/min

P wave

  • Absent

PR interval

  • Unmeasurable

QRS complex

  • Wide and bizarre

T wave

  • Deflection opposite QRS complex

QT interval

  • 0.60 second

Other

  • None


What Causes It ⬆ ⬇

  • Digoxin toxicity
  • Drugs
    • Beta-adrenergic blockers
    • Calcium channel blockers
    • Tricyclic antidepressants
  • Failure of all of the heart's higher pacemakers
  • Failure of supraventricular impulses to reach the ventricles because of a block in the conduction system
  • Metabolic imbalance
  • MI

  • Myocardial ischemia
  • Pacemaker failure
  • Sick sinus syndrome
  • Third-degree heart block
On the line

Identifying accelerated idioventricular rhythm

An accelerated idioventricular rhythm has the same characteristics as an idioventricular rhythm except that it's faster. The rate shown here varies between 40 and 100 beats/min.

What to Look for ⬆ ⬇

  • Evidence of sharply decreased cardiac output (such as hypotension, dizziness, feeling of faintness, light-headedness, and syncope) if the patient has a continuous idioventricular rhythm
  • Difficult auscultation or palpation of blood pressure

How It's Treated ⬆

  • Treatment should begin immediately to increase heart rate, improve cardiac output, and establish a normal rhythm.
  • Treatment isn't intended to suppress the idioventricular rhythm because this arrhythmia acts as a safety mechanism against ventricular standstill.
  • Never treat an idioventricular rhythm with antiarrhythmic drugs (such as amiodarone or lidocaine) because these drugs suppress the escape beats.
  • Atropine may be given to increase heart rate. If atropine isn't effective or the patient develops hypotension or other evidence of clinical instability, a pacemaker may be inserted to reestablish a heart rate and cardiac output sufficient to perfuse organs.
  • A transcutaneous pacemaker may be used in an emergency until a transvenous pacemaker can be inserted.
  • Maintain continued ECG monitoring and periodically assess the patient until hemodynamic stability has been restored.
  • Keep atropine and pacemaker equipment readily available.
  • Enforce bed rest until an effective heart rate has been maintained and the patient is stable.
  • Tell the patient and his family about the serious nature of this arrhythmia and the treatment it requires.
  • If the patient needs a permanent pacemaker, explain how it works, how to recognize problems, when to contact a doctor, and how pacemaker function will be monitored.