An idioventricular rhythm is a cardiac rhythm characterized by a rate of <50 beats per minute (bpm), absence of P waves and widening of the QRS complex. In cases where the heart rate is between 50 and 110 bpm, it is known as

accelerated idioventricular rhythm Accelerated idioventricular rhythm is a ventricular rhythm with a rate of between 40 and 120 beats per minute. Idioventricular means “relating to or affecting the cardiac ventricle alone” and refers to any ectopic ventricular arrhythmia. Accel ...

and

ventricular tachycardia Ventricular tachycardia (V-tach or VT) is a fast heart rate arising from the lower chambers of the heart. Although a few seconds of VT may not result in permanent problems, longer periods are dangerous; and multiple episodes over a short period ...

if the rate exceeds 120 bpm. Causes of idioventricular rhythms are varied and can include drugs or a heart defect at birth. It is typically benign and not life-threatening.

Etiology

Various etiologies may contribute to the formation of an idioventricular rhythm, and include: *

Heart block Heart block (HB) is a disorder in the heart's rhythm due to a fault in the natural pacemaker. This is caused by an obstruction – a block – in the electrical conduction system of the heart. Sometimes a disorder can be inherited. Despite the se ...

* Reperfusion after

myocardial infarction A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may tra ...

* Electrolyte abnormalities * Heart diseases present at birth * Certain drugs (eg.

digoxin Digoxin (better known as Digitalis), sold under the brand name Lanoxin among others, is a medication used to treat various heart conditions. Most frequently it is used for atrial fibrillation, atrial flutter, and heart failure. Digoxin is on ...

, β-agonists, anaesthetics)

Pathophysiology

The physiological pacemaker of the heart is the

sinoatrial node The sinoatrial node (also known as the sinuatrial node, SA node or sinus node) is an oval shaped region of special cardiac muscle in the upper back wall of the right atrium made up of cells known as pacemaker cells. The sinus node is approximat ...

. If the sinoatrial node is rendered dysfunctional, the

AV node The atrioventricular node or AV node electrically connects the heart's atria and ventricles to coordinate beating in the top of the heart; it is part of the electrical conduction system of the heart. The AV node lies at the lower back section of t ...

may act as the pacemaker.{{cite book , last1=Guyton , first1=Arthur C. , last2=Hall , first2=John E. , title=Textbook of Medical Physiology , pages=120-121 , edition=11 If both of these fail, the ventricles begin to act as the dominant pacemaker in the heart. The ventricles acting as their own pacemaker gives rise to an idioventricular rhythm.

Diagnosis

An ECG trace is required for diagnosis.

Treatment

As this rhythm is not life-threatening, treatment has limited value for the patient. If underlying pathologies are identified, they should be treated appropriately. Antidysrhythmics may be utilised if the patient suffers from dysrhythmias.

References

Cardiac arrhythmia