Case Description
50-year-old male with past medical history of severe non-ischemic cardiomyopathy necessitating HeartMate 3 LVAD implantation, who presented with multiple ineffective shocks by his Medtronic single chamber dual coil ICD. On thorough history, he described his ICD shocks as “brick hit my face”. The patient had no history of ICD shocks in the past and this was his first presentation for ICD shocks after LVAD implantation surgery. He was not on any antiarrhythmic drugs at the time of presentation. On physical examination, the patient was awake and conversant with a mean arterial blood pressure (MAP) of 79 mm of Hg, oxygen saturation of 97% on room air, and heart rate of 92 beats per minute (bpm). He was noted to be wearing a large metal ring on his tongue. (Figure A) His lungs were clear to auscultation and he had a normal LVAD hum over the precordium. His HM3 interrogation displayed a flow rate of 4.2 liters/minute, using 4 watts of power at a speed of 5400 revolutions per minute. Initial electrocardiogram (ECG) demonstrated normal sinus rhythm with premature ventricular contractions (PVCs). ICD interrogation demonstrated an episode of sustained VT at a rate of around 240 bpm, lasting approximately 43 second. The patient received anti tachycardia pacing (ATP) followed by two failed ICD shocks without termination of the VT. He then, spontaneously converted to normal sinus rhythm just prior to delivery of the third shock (35.9 J with impedance of 58 ohms). Initial laboratory work was significant for serum creatinine of 1.5 mg/dL from a baseline of 0.9-1.0 mg/dL, potassium level of 4.3 mmol/L and magnesium level of 2.2 mg/dL. Cardiac electrophysiology (EP) team was consulted, and patient was admitted to the cardiac intermediate care unit.
Given the unusual description of his ICD shock, i.e., “brick hitting his face”, and presence of a sizable metal tongue ring, raised the possibility that his metal tongue ring might have affected the shock effectiveness by changing the vector. Hence, we decided to perform noninvasive programmed stimulation and test the effectiveness of his ICD shocks after removal of the metal tongue ring. The patient was brough to the EP lab, his metal tongue ring was removed, and his ICD was programmed to shock at 25 J, which was 10 J lower than his previously programmed shock output. Next, sustained VT was induced with a T wave shock. The patients ICD appropriately detected VT and delivered a 25 J shock, which successfully terminated the rhythm. Additionally, the shock impedance after removal of the tongue ring was noted to be 73 ohms, which was higher when compared to 58, 66 and 67 ohms from his initial shocks. (Table 1.)