Hello, I'm an expert in cardiology with a focus on electrophysiology. When we talk about a wide QRS complex, we're referring to a specific feature seen on an electrocardiogram (ECG), which is a test that records the electrical activity of the heart.

A normal QRS complex, which represents the ventricular depolarization phase during a heartbeat, is typically less than 120 milliseconds in duration. When the QRS complex is wider than this, it's considered "wide." A wide QRS can be a sign of various conditions, including:


1. Bundle branch block: This is a common cause of a wide QRS and occurs when there's a delay in the electrical conduction through the heart's ventricles.

2. Ventricular hypertrophy: Enlargement of the heart's ventricles can also lead to a wide QRS.

3. Myocardial infarction (heart attack): Damage to the heart muscle can alter the electrical conduction pathways, resulting in a wide QRS.

4. Certain medications: Some drugs can affect the heart's electrical activity and cause a wide QRS.

5. Hyperkalemia: High levels of potassium in the blood can also lead to a wide QRS.

It's important to note that a wide QRS complex itself is not a diagnosis but rather a finding that requires further investigation to determine the underlying cause.

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Wide, bizarre QRS complexes of supraventricular origin are often the result of intraventricular conduction defect which usually occurs due to right or left bundle branch block. ? Wide QRS complexes may be seen in aberrant conduction, ventricular preexcitation and with a cardiac pacemaker.read more >>