Case report: Masked premature ventricular contractions and Intradevice interaction causing ventricular Arrythmias.

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• Implantable cardioverter-defibrillators (ICDs) are crucial for managing life-threatening ventricular arrhythmias.
• Rarely, ICDs can paradoxically precipitate arrhythmias due to device-patient interactions.
• Cardiac sarcoidosis is an inflammatory condition that can affect the heart's electrical system.

Purpose of the Study:

• To report a rare case of ICD-induced polymorphic ventricular tachycardia and ventricular fibrillation.
• To elucidate the specific intradevice timing mechanism leading to arrhythmia precipitation.
• To emphasize the importance of tailored ICD programming in preventing device-related complications.

Main Methods:

• Case report of a 44-year-old male patient with cardiac sarcoidosis.
• Analysis of the interaction between premature ventricular contractions (PVCs) and the ICD's ventricular blanking period.
• Device reprogramming from DDD to VVI mode as an intervention.

Main Results:

• The patient experienced recurrent polymorphic ventricular tachycardia (VT) and ventricular fibrillation (VF).
• PVCs were masked by the ICD's post-atrial pacing ventricular blanking period.
• This "R-on-T" phenomenon, triggered by ventricular pacing during the vulnerable period, induced VT/VF.
• Reprogramming to VVI mode successfully eliminated device-induced arrhythmias.

Conclusions:

• Individualized ICD programming is essential to prevent device-induced arrhythmias.
• Understanding intradevice timing interactions is critical for managing patients with complex cardiac conditions.
• This case underscores the need for careful evaluation of ICD behavior in patients prone to arrhythmias.