What is the most common cause of inappropriate ICD therapy?

What is the most common cause of inappropriate ICD therapy?

• A. SVT
• B. VT
• C. Afib with rapid ventricular response
• D. NSR

Answer: (A)

The key idea is that ICDs can misinterpret fast rhythms as VT. When a supraventricular rhythm runs very quickly, especially atrial fibrillation with rapid ventricular response or other SVTs with aberrant conduction, the device’s detection algorithms may categorize it as ventricular tachycardia and deliver therapy inappropriately. SVT is the broad category that encompasses these fast SV rhythms, making it the most common source of inappropriate ICD shocks. True VT would be an appropriate therapy, and NSR would not trigger therapy, so they’re less likely explanations for inappropriate shocks. By understanding that misclassification of rapid SVT as VT is the frequent culprit, you’re recognizing why SVT is the best answer here.

The key idea is that ICDs can misinterpret fast rhythms as VT. When a supraventricular rhythm runs very quickly, especially atrial fibrillation with rapid ventricular response or other SVTs with aberrant conduction, the device’s detection algorithms may categorize it as ventricular tachycardia and deliver therapy inappropriately. SVT is the broad category that encompasses these fast SV rhythms, making it the most common source of inappropriate ICD shocks. True VT would be an appropriate therapy, and NSR would not trigger therapy, so they’re less likely explanations for inappropriate shocks. By understanding that misclassification of rapid SVT as VT is the frequent culprit, you’re recognizing why SVT is the best answer here.