Mr. K is a 63-year-old Caucasian man with history of coronary artery disease (CAD) with previous coronary interventions of stent implantations in the left anterior descending and circumflex coronary arteries. His most recent left ventricular ejection fraction (LVEF) is 30%. He has an automatic implantable cardioverter defibrillator (AICD) for primary prevention of sudden cardiac death. He has been receiving optimally uptitrated guideline-directed medical therapy (GDMT) for his heart failure (HF) including carvedilol 25 mg twice daily, lisinopril 20 mg daily, and spironolactone 25 mg daily for more than 12 months. His other medications include aspirin 81 mg daily, atorvastatin 40 mg daily, furosemide 40 mg daily, and potassium chloride 40 mEq daily. He denies angina but reports dyspnea while walking less than 2 blocks, which is stable compared to last year. He denies any resting dyspnea or orthopnea. He has had no hospitalizations for HF exacerbation over the past 12 months. He denies any angina. He has been compliant with his medications and adherent to a low-salt diet. On exam, he appears well-nourished and in no acute distress. His heart rate is 65 bpm and regular. Respirations are 16/minute. Blood pressure is 108/65. His cardiac examination reveals a regular rate and rhythm, and a sustained, laterally displaced apical impulse. There were no extra heart sounds or murmurs. His extremities were warm with no edema. His jugular venous pressure appears to be within normal limits and lungs were clear. His electrocardiogram shows sinus rhythm with a narrow QRS complex. Laboratory tests showed both liver and kidney function to be normal. His echocardiography showed LVEF of 30% and LV end-diastolic diameter of 65 mm.
HF, a disease with high mortality and increasing prevalence,1 is characterized by autonomic imbalance, including decreased parasympathetic tone,2,3 hyperactive sympathetic tone,4,5 and impaired baroreflex control of sympathetic activity (Figure 29-1).6,7 Thus far, the drugs shown to improve survival in systolic HF—beta blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), aldosterone receptor antagonists, and the newest class approved angiotensin receptor-neprilysin inhibitors (ARNIs)—all possess sympatholytic effects and thus help restore autonomic imbalance in patients with systolic HF. For Mr. K, he has already been receiving GDMT and the dosages of his medications are optimally titrated. He is euvolemic on exam ination but still has baseline New York Heart Association (NYHA) class III symptoms.
Autonomic dysfunction in heart failure. An imbalance of a naturally Yin and Yang control of the heart characterized by sympathetic overdrive and parasympathetic withdrawal. The detrimental consequences include, but are not limited to, increase in heart rate, arrhythmogenesis, nitric oxide dysregulation, and proinflammatory state. (From http://www.biocontrol-medical.com.)
Although not FDA-approved, several approaches of autonomic ...