History
The patient was a nonsmoker. He had experienced a myocardial infarction in 2003. A coronary angiogram performed in 2003 showed severe left main artery disease and triple vessel disease. He underwent coronary artery bypass grafting (CABG) the same year. Echocardiography was done 6 months after CABG showed left ventricular ejection fraction (LVEF) of 25%. He was diagnosed with New York Heart Association (NYHA) class III disease, and electrocardiography showed sinus rhythm with a left bundle branch block pattern. QRS duration was 150 msec, and no history of ventricular arrhythmia was reported. In view of persistent left ventricular systolic dysfunction and underlying wide QRS duration, cardiac resynchronization therapy with defibrillator (CRT-D) backup was performed. The procedure was uneventful, and the left ventricular lead was inserted in the posterolateral branch of the coronary sinus. He was subsequently followed regularly by the combined heart failure and device clinic.
The patient returned 6 months after CRT-D implantation and was found to be clinically still in NYHA class III. Device interrogation showed that he received 85% biventricular pacing. Other parameters were unremarkable. Follow-up echocardiographic examination showed an LVEF of 25%.
Comments
The patient was both clinically and echocardiographically a CRT nonresponder. It was necessary to explore the potential cause of lack of CRT response.
Current Medications
The patient’s medications are aspirin 80 mg daily, metoprolol controlled-release 12.5 mg daily, ramipril 1.25 mg daily, furosemide 20 mg daily, and simvastatin 20 mg daily.
Comments
The patient received most of the guideline-recommended medications. However, the dosage was not optimal.
Current Symptoms
The patient experienced persistent heart failure symptoms after CRT-D implantation.
Comments
The cause of the patient’s nonresponse to CRT needs to be identified. It is likely due to suboptimal biventricular pacing and suboptimal medical therapy.
Physical Examination
Comments
The patient was clinically in NYHA class III heart failure.
