AHA/ACC/HFSA Guidelines Implementation Case Series: Resynchronization Pacing Preferred in Patients With Reduced Ejection Fraction

A 68-year-old woman presented with 2 days of shortness of breath on exertion and fatigue. She denied syncope, chest pain, or leg swelling. She has known chronic obstructive pulmonary disease, type 2 diabetes, and hypertension. She underwent cardiac catheterization 1 year before this admission for concern for unstable angina, which showed nonobstructive coronary artery disease. She had normal left ventricular (LV) function by echocardiogram at that time and normal atrioventricular conduction. She has no known family history of cardiac disease or sudden death. She has no notable social history. She is on amlodipine and chlorthalidone for hypertension. Notable vitals included a pulse of 41 beats per minute and blood pressure 167/100. Physical examination was significant for nondistended jugular venous pressure with cannon a wave, variable S1, normal S2, and no murmurs. ECG revealed sinus rhythm, atrioventricular dissociation with ventricular escape rhythm at 36 bpm consistent with complete heart block (Figure 1).

Laboratories demonstrated potassium of 4.0, serum creatinine 1.0, undetectable troponin, normal thyroid stimulating hormone, and complete blood count. Transthoracic echocardiogram showed normal LV cavity size, mild LV hypertrophy with LV ejection fraction (EF) of 40% to 45%, mild global hypokinesis, normal right ventricular size, and function with no significant valvular abnormalities. The patient was diagnosed with Stage C heart failure with mildly reduced EF. Evaluation for potential etiologies of the ventricular dysfunction and bradycardia was unrevealing. The patient was planned for permanent pacemaker implantation along with guideline-directed medical therapy implementation.