A 77-year-old man with a 5-year history of idiopathic cardiomyopathy is evaluated for progressive exertional fatigue and dyspnea. He has recently stopped carrying groceries in from the car because of his exertional dyspnea. He had an implantable cardioverter-defibrillator placed 3 years ago. Medical history is also significant for hypertension. Medications are lisinopril, 40 mg/d; metoprolol succinate, 25 mg/d; furosemide, 40 mg/d; and spironolactone, 25 mg/d.
On physical examination, blood pressure is 94/60 mm Hg and pulse rate is 70/min. Estimated central venous pressure is 5 cm H2O. There is no edema.
Serum electrolyte levels and kidney function are normal. Electrocardiogram shows normal sinus rhythm, a PR interval of 210 ms, QRS duration of 160 ms, and a new left bundle branch block.
His left ventricular ejection fraction 3 months ago was 25%.
Which of the following is the most appropriate next step in management?
A. Cardiac resynchronization therapy
B. Dobutamine therapy
C. Increase furosemide dose
D. Left ventricular assist device placement
MKSAP Answer and Critique
The correct answer is A. Cardiac resynchronization therapy. This item is available to MKSAP 17 subscribers as item 56 in the Cardiovascular Medicine section. More information is available online.
This patient with symptomatic heart failure and a reduced left ventricular ejection fraction with evidence of significant conduction system disease should undergo placement of a biventricular pacemaker (cardiac resynchronization therapy [CRT]). He has progressive heart failure symptoms while on appropriate medical therapy and has New York Heart Association (NYHA) functional class III symptoms. With his ejection fraction less than 35% and left bundle branch block (LBBB), he is a candidate for a biventricular pacemaker, which has been demonstrated to reduce mortality and symptoms in patients with NYHA functional class III and IV heart failure by improving cardiac hemodynamics. The 2013 American College of Cardiology Foundation/American Heart Association/Heart Rhythm Society(ACCF/AHA/HRS) guideline recommends CRT in patients with an ejection fraction of 35% or below, NYHA functional class III to IV symptoms on guideline-directed medical therapy, and LBBB with QRS duration greater than or equal to 150 ms. This patient already has an implantable cardioverter-defibrillator, which is indicated for patients with NYHA functional class II to III heart failure and an ejection fraction less than 35%. Now that he has developed a LBBB and an increase in symptoms, it is reasonable to proceed with placement of a biventricular pacemaker as well.
Inotropic therapy, such as dobutamine, is reserved for patients with end-stage heart failure, either as a bridge to transplantation or for palliative care. Patients in this category often have recurrent hospitalizations for heart failure, have evidence of end-organ compromise such as worsening kidney and liver function, and have very poor exercise tolerance. Although this patient has progressive symptoms, he has not reached this stage yet, and has no indication for inotropic therapy.
The patient has no evidence of volume overload on examination and a borderline low blood pressure; therefore, increasing his diuretic dose would not be expected to improve his symptoms and may worsen them by lowering his cardiac filling pressures and cardiac output.
The patient is fairly symptomatic but has not yet had optimal therapy, as he has an indication for CRT and has not yet received it. Left ventricular assist devices (LVADs) are reserved for patients with end-stage refractory heart failure as a bridge to heart transplantation or as destination therapy in selected patients who are not candidates for transplantation. However, prior to being considered for either an LVAD or heart transplantation, a patient must be on optimal medical therapy.
- Cardiac resynchronization therapy is recommended in patients with an ejection fraction of 35% or below, New York Heart Association functional class III to IV symptoms on guideline-directed medical therapy, and left bundle branch block or QRS duration of 150 ms or greater.