What are the likely causes and appropriate work‑up for nocturnal wheezing in a 75‑year‑old man with atrial fibrillation, hypertension, hyperlipidemia and prior ischemic stroke?

Nocturnal Wheezing in a 75-Year-Old with Atrial Fibrillation and Prior Stroke

This patient's nocturnal wheezing most likely represents cardiac asthma from heart failure or sleep-disordered breathing (obstructive sleep apnea), both of which are strongly associated with atrial fibrillation and stroke in elderly patients.

Primary Differential Diagnosis

Cardiac Asthma from Heart Failure

• Left ventricular systolic dysfunction predicts ischemic stroke in atrial fibrillation patients and is strongly associated with heart failure 1
• Heart failure is a component of the CHADS2 score (this patient scores ≥4: age 75 years [1 point], hypertension [1 point], prior stroke [2 points], totaling at minimum 4 points) 1
• Nocturnal dyspnea/wheezing occurs when recumbent position increases venous return and pulmonary congestion 1
• Atrial fibrillation itself is associated with increased mortality and heart failure independent of other vascular risk factors 1

Sleep-Disordered Breathing (Obstructive Sleep Apnea)

• Sleep-disordered breathing carries a 2.38 relative risk of heart failure and is extremely common in stroke patients, occurring in 58% of ischemic stroke patients 1, 2
• Nocturnal desaturation from OSA is independently associated with atrial fibrillation in stroke patients (OR 1.19 per 1% desaturation increase) 3
• Age, diabetes, nighttime stroke onset, and male gender are independent predictors of sleep-disordered breathing in stroke patients 2
• OSA prevalence reaches 17% with severe disease (AHI ≥30) in stroke populations 2

Essential Diagnostic Work-Up

Immediate Evaluation

• Brain natriuretic peptide (BNP) or NT-proBNP to assess for heart failure (elevated levels strongly suggest cardiac etiology)
• Transthoracic echocardiogram to evaluate left ventricular ejection fraction, left atrial size, and diastolic dysfunction 1, 4
  • Left atrium ≥4.0 cm occurs in 81.3% of atrial fibrillation patients with stroke (OR 5.85) 4
  • Ejection fraction <50% occurs in 27.7% of atrial fibrillation stroke patients (OR 2.63) 4
• Overnight pulse oximetry as initial screening for nocturnal hypoxemia 3
• Chest X-ray to evaluate for pulmonary edema, cardiomegaly, or alternative pulmonary pathology

Secondary Evaluation if Initial Tests Suggest OSA

• Formal polysomnography in a sleep center if overnight oximetry shows desaturation or clinical suspicion remains high 2, 3
• Epworth Sleepiness Scale assessment 2

Critical Clinical Details to Elicit

• Timing: Does wheezing occur specifically when lying flat? Does it improve when sitting upright? (suggests cardiac asthma)
• Associated symptoms: Orthopnea, paroxysmal nocturnal dyspnea, lower extremity edema (cardiac), versus witnessed apneas, snoring, daytime somnolence (OSA)
• Body habitus: Neck circumference, body mass index (OSA risk factors) 2
• Witnessed apneas or gasping during sleep 2

Management Implications

If Heart Failure is Confirmed

• Optimize heart failure therapy per ACC/AHA guidelines, as LV systolic dysfunction increases stroke risk in atrial fibrillation 1
• Consider device therapy if ejection fraction remains reduced despite optimal medical therapy 1

If Sleep-Disordered Breathing is Confirmed

• Continuous positive airway pressure (CPAP) therapy improves LV structure and function in patients with LV dysfunction and sleep apnea 1
• CPAP produces symptomatic improvement and may reduce stroke recurrence risk 1, 2
• However, long-term CPAP compliance is poor (only 15% continue chronically) 2

Anticoagulation Optimization is Critical Regardless of Etiology

• This patient has a CHADS2 score of ≥4 (very high stroke risk >7%/year) and requires warfarin with INR 2-3 1
• Hypertension control is critically important before and during anticoagulation, as uncontrolled hypertension increases both ischemic stroke risk and intracerebral hemorrhage risk 1, 5
• Target blood pressure <140/90 mmHg, ideally <130/80 mmHg 6
• For patients >75 years, some experts recommend INR target 1.6-2.5, though others favor 2-3 for all ages 1

Common Pitfalls to Avoid

• Do not attribute nocturnal wheezing solely to "asthma" or "COPD" without echocardiographic evaluation in elderly patients with atrial fibrillation 1, 4
• Do not overlook sleep-disordered breathing, as it affects 58% of stroke patients and independently predicts mortality 2
• Do not delay or withhold anticoagulation in this very high-risk patient (prior stroke + atrial fibrillation) - the stroke recurrence rate is 10.8 per 100 patient-years without anticoagulation 1
• Elderly patients (≥75 years) have twice the bleeding risk on anticoagulation, but this does not contraindicate treatment when stroke risk is high 1
• Ensure blood pressure is controlled before intensifying anticoagulation, as intracerebral hemorrhage is "exquisitely sensitive" to blood pressure control 1