A 60-year-old ICD patient with comorbid conditions

A 60-year-old man with left ventricular dysfunction resulting

from nonischemic cardiomyopathy was followed in an ambulatory heart failure clinic. He had no history of myocardial infarction (MI), cardiac arrest, or symptomatic ventricular tachycardia. His noncardiac comorbid conditions included a previous stroke with no residual deficits, atrial fibrillation, and atrioventricular nodal disease, warranting insertion of a biventricular pacemaker. Although he had New York Heart Association functional class III heart failure, he continued to work as a medical professional. His medications included 6.25 mg of carvedilol (Coreg) twice daily, 40 mg of furosemide (Lasix) twice daily, 0.125 mg of digitalis daily, 5 mg of ramipril (Altace) twice daily, 3 mg of warfarin (Coumadin) daily, 10 mg of paroxetine (Paxil) daily, coenzyme Q daily, and a multivitamin daily.

At the initial baseline examination, the patient had a left ventricular ejection fraction (LVEF) of 0.23, documented by radionuclide angiography. A baseline echocardiogram showed an enlarged left ventricle, with dimensions of 62 mm in end-diastole and 53 mm in end-systole. There was moderate-to-severe mitral regurgitation, mild-to- moderate tricuspid regurgitation, and a right ventricular systolic pressure of 50 mm Hg demonstrated by echocardiography.

The patient’s laboratory values were as follows: hemoglobin, 16.3 g/dL; white blood cell count, 7.7 x 103/μL; platelet count, 164 x 103/μL; sodium, 141 mmol/L; and potassium, 4.1 mmol/L. His creatinine level was 1.66 mg/dL (147 mmol/L), with a calculated estimated glomerular filtration rate of 44 mL/min. His 12-lead electrocardiogram showed a paced rhythm, with a QRS duration of 208 ms. Several years after initial presentation, the patient received an implantable cardioverter-defibrillator (ICD) for primary prevention, based on SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial) criteria. A dual-chamber Atlas TM

HF V 341 device was implanted uneventfully without any peri-implant complications.

During longitudinal cardiac surveillance, the patient’s cardiac status began to exhibit signs of deterioration. His left ventricular size and systolic function worsened on serial evaluation: the left ventricle enlarged to 65 mm in end-diastole and 56 mm in end-systole, and his LVEF was estimated to be <0.20. These changes were accompanied by a decline in systolic blood pressure and worsening functional status. His peak oxygen consumption was initially 19.4 mL/kg/min, but declined during serial evaluation to 9.7 mL/kg/min (37% predicted). He was referred for cardiac transplant evaluation.

While awaiting a donor heart, the patient was hospitalized after an episode of syncope. On admission, he had underlying atrial fibrillation and was ventricularly paced achieving a rate of 80 beats/min; his blood pressure was 94/62 mm Hg, and his oxygen saturation was 95% on room air. The patient was afebrile. The jugular venous pressure was 5 cm above the sternal angle, and no S3 was audible. His chest was clear on auscultation, and there was no peripheral edema. At the time of presentation, his hemoglobin level was 13.8 g/dL, serum sodium level was 127 mmol/L, and serum creatinine level had worsened to 2.22 mg/dL (196 mmol/L). Examination of his ICD showed that he had experienced numerous episodes of ventricular tachycardia at rates between 120 and 160 beats/min, resulting in antitachycardia pacing and multiple shocks from his ICD. The patient was admitted to the Coronary Care Unit, where intravenous amiodarone (Cordarone, Pacerone) and mexiletine (Mexitil) were administered. His ICD was reprogrammed so that only ventricular rates between 140 and 160 beats/min were monitored. The patient continued to have episodes of sustained slow ventricular tachycardia, with associated lightheadedness, nausea, and diaphoresis.

An electrophysiology study was planned; however, the evening before the procedure, the patient became asystolic, with failure to capture despite active ventricular pacing. Cardiopulmonary resuscitation was initiated, the patient was intubated, and after 45 minutes of advanced cardiac life support, his pulse returned. Neurologic recovery from this event was poor, and after discussion with the family, life support was withdrawn. Autopsy results showed cardiomegaly, with a cardiac mass of 600 g, dilatation of all heart chambers, and extensive regions of interstitial fibrosis.