Fatigue and Heart Disease
A 49-year-old Caucasian man with heart failure (HF) is referred to the sleep disorders center for evaluation of sleep apnea. He denies any sleep complaints and questions why he was referred for a sleep study. He typically goes to bed at 11 p.m. and falls asleep within a few minutes. He wakes up five to seven times per night for no apparent reason other than an occasional abrupt arousal feeling short of breath. His usual wake up time is 7 a.m., and he generally feels refreshed in the morning. He estimates a total sleep time of 8 hours. He is a habitual supine sleeper and his wife rarely notes light snoring which resolves when he rolls onto his side. He and his wife deny gasping, choking, or breathing pauses in sleep as well as daytime sleepiness (his Epworth Sleepiness Scale score is 6). However, he reports fatigue since a myocardial infarction one year prior that has affected his ability to participate in activities he enjoys, including golf and gardening. He typically drinks three 8-oz cups of coffee per day and denies using alcohol and recreational drugs.
His medical history is significant for Type II DM, MI complicated by HF, and recurrent AF status post placement of an implantable cardioverter defibrillator. Current medications include aspirin, clopidogrel, atorvastatin, lisinopril, carvedilol, spironolactone, furosemide, and digoxin. He has a 20-pack year tobacco history but quit one year prior to presentation. A trans-thoracic echocardiogram shows normal left ventricular size, ejection fraction of 15%, severe hypokinesis of the mid inferior and anterior left ventricular segments with Stage 3 diastolic function, and normal right ventricle size and systolic function. Laboratory results include BNP of 105 pg/ml (normal: 0-99) and normal hemoglobin, thyroid stimulating hormone, and electrolytes.
Physical examination reveals a blood pressure of 122/88 mm Hg, pulse of 88 beats per minute, respiratory rate of 18 breaths per minute, weight of 140 kg, height of 186 cm (BMI 41 kg/m2), and neck circumference of 46 cm. The oropharnyx is crowded with a Grade III Friedman tongue position. Heart exam is significant for an irregularly irregular rhythm without murmur. Lungs are clear. There is no jugular venous distention. Mild edema to the distal calves is present.
A five minute representative epoch from the overnight polysomnogram shows the following:
Figure legend: Recurrent respiratory events are observed in the nasal pressure, airflow, and effort channels that are associated with microarousals on the EEG, oxygen desaturations, and fluctuations in CO2. Channels are as follows: electro-oculogram (left: E1-M2, right: E2-M1), chin electromyogram (Chin), electroencephalogram (left frontal [F3], central [C3], and occipital [O1] electrodes to right mastoid [M2] reference), EKG, snore microphone, leg EMG (right and left tibialis anterior placements), nasal pressure transducer, nasal-oral airflow, respiratory effort (thoracic, abdominal) and oxygen saturation (SaO2), and end-tidal CO2 (ETCO2).
Which of the following statements best reflect the clinical presentation and polysomnographic findings?