As a medical professional with expertise in cardiology, I can explain what it means to have a long QRS complex.

The QRS complex on an electrocardiogram (ECG or EKG) represents the electrical activity of the ventricles as they depolarize, or contract. A normal QRS duration is typically between 0.06 to 0.10 seconds. When the QRS complex duration is prolonged, meaning it lasts longer than 0.10 seconds, it is referred to as having a long QRS. This can be an indication of various cardiac conditions, including:


1. Bundle branch block: A delay in the electrical conduction through the left or right bundle branches of the heart can cause a wide QRS complex.

2. Myocardial infarction (heart attack): Damage to the heart muscle can disrupt the normal electrical conduction pathways, leading to a prolonged QRS.

3. Cardiomyopathy: Conditions that affect the heart muscle can alter the electrical conduction and result in a long QRS.

4. Intraventricular conduction delay: This is a broader term that includes conditions that delay the electrical signal as it travels through the ventricles.

5. Hyperkalemia: High levels of potassium in the blood can affect the electrical activity of the heart and prolong the QRS.

A long QRS complex can also be seen in individuals with ventricular hypertrophy or in those who are taking certain medications that affect cardiac conduction.

It's important to note that a long QRS complex is not a diagnosis in itself 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 >>