Pacemaker/ICD Puzzle<br />

Clinical History A 56-year-old female with non-ischemic dilated cardiomyopathy, an ejection fraction of 25%, congestive heart failure, recurrent atrial fibrillation, pulmonary hypertension, and hyperlipidemia, states that she has periodic palpitations associated with shortness of breath. She denies chest pain, orthopnea, dizziness, and syncope. Device History S/P ICD implantation: ICD: Medtronic D154ATG EnTrust A Lead: Medtronic 5076 CapSure Fix Novus V Lead: Medtronic 6949 Sprint Fidelis Medications Coreg: 6.25 mg bid Digoxin: 0.25 mg qd Lasix: 80 mg bid Lisinopril: 10 mg qd Spironolactone: 25 mg, 1/2 tab qd Warfarin (as directed) Lipitor: 20 mg qd Zyrtec: 10 mg qd Physical Examination On examination, there was no JVD, chest sounds were clear to auscultation, heart sounds were regular with a normal S1, S2 without rubs, murmurs or gallops, and no edema. Device evaluation revealed normal ICD function: No ventricular tachyarrhythmias No atrial fibrillation No change in atrial and ventricular stimulation and sensing thresholds 24-hour Holter revealed this ECG (See Figure 1) Pacemaker/ICD Puzzle Question: Which of the following is demonstated in the Holter recording shown in Figure 1? A: Ventricular oversensing B: Loss of ventricular capture C: Concealed conduction D: Crosstalk inhibition E: Normal device function Readers, email your guesses to jelrod@hmpcommunications.com. The correct answer will be revealed in next month s issue!