What is the expected morphology of the QRS complex during a PVC?

What is the expected morphology of the QRS complex during a PVC?

• A. Narrow and regular
• B. Wide and abnormal
• C. Normal and consistent
• D. Absent entirely

Answer: (B)

The morphology of the QRS complex during a premature ventricular contraction (PVC) is expected to be wide and abnormal. This is due to the fact that PVCs originate in the ventricles, bypassing the normal conduction pathway through the atrioventricular (AV) node, which typically results in a faster conduction velocity. The ventricular myocardium generates a QRS complex that is wider than the normal QRS, often measuring greater than 0.12 seconds. This widening occurs because the electrical impulse spreads through the ventricles more slowly than it does through the normal conduction system, leading to a disruption in the usual depolarization pattern. Additionally, the shape of the QRS during a PVC can vary, appearing bizarre or different from the usual QRS complexes, which can be described as abnormal. Understanding this aspect is crucial for ECG interpretation, particularly in distinguishing PVCs from other arrhythmias. The other choices reflect characteristics that do not align with the typical presentations seen with PVCs. Therefore, recognizing the expected wide and abnormal QRS morphology during PVCs is essential for accurate ECG assessment.

The morphology of the QRS complex during a premature ventricular contraction (PVC) is expected to be wide and abnormal. This is due to the fact that PVCs originate in the ventricles, bypassing the normal conduction pathway through the atrioventricular (AV) node, which typically results in a faster conduction velocity. The ventricular myocardium generates a QRS complex that is wider than the normal QRS, often measuring greater than 0.12 seconds. This widening occurs because the electrical impulse spreads through the ventricles more slowly than it does through the normal conduction system, leading to a disruption in the usual depolarization pattern.

Additionally, the shape of the QRS during a PVC can vary, appearing bizarre or different from the usual QRS complexes, which can be described as abnormal. Understanding this aspect is crucial for ECG interpretation, particularly in distinguishing PVCs from other arrhythmias. The other choices reflect characteristics that do not align with the typical presentations seen with PVCs. Therefore, recognizing the expected wide and abnormal QRS morphology during PVCs is essential for accurate ECG assessment.