What are the potential causes of sudden congestive heart failure (CHF) exacerbation in a patient with a history of CHF?

Etiology of Sudden CHF Exacerbation

The most common precipitants of sudden CHF exacerbation are medication and dietary nonadherence (particularly sodium/fluid restriction), acute myocardial ischemia, uncontrolled hypertension, and atrial fibrillation, with nearly 50% of patients presenting with blood pressure >140/90 mm Hg at admission. 1

Primary Cardiovascular Precipitants

Acute Coronary Ischemia

• Acute myocardial ischemia is one of the most critical precipitants requiring immediate ECG and troponin assessment, as it directly determines mortality risk 1, 2
• Unstable coronary syndrome can trigger sudden decompensation even in previously stable patients 1

Hypertensive Crisis

• Uncontrolled or accelerated hypertension is particularly important in blacks, women, and those with HFpEF 1
• Abrupt discontinuation of antihypertensive therapy may precipitate acute worsening 1
• Nearly 50% of ADHERE registry patients admitted with HF had BP >140/90 mm Hg 1

Arrhythmias

• Atrial fibrillation occurs in >30% of patients with acute HF and increases metabolic demands 1
• Other symptomatic tachyarrhythmias can trigger decompensation 1
• New-onset AF or rapid ventricular response in existing AF commonly precipitates exacerbations 1

Medication-Related Causes

Nonadherence

• Medication nonadherence for financial or other reasons is a major cause of hospital admission 1
• Discontinuation of guideline-directed medical therapy leads to rapid deterioration 1

Iatrogenic Precipitants

• Recent addition of negative inotropic drugs (verapamil, nifedipine, diltiazem, beta blockers when initiated inappropriately) 1
• NSAIDs and COX-2 inhibitors cause sodium retention 1
• Thiazolidinediones increase fluid retention 1
• Glucocorticoids promote salt retention 1
• Antiarrhythmic agents (except amiodarone) may depress ventricular function 1
• Over-the-counter agents like pseudoephedrine 1

Dietary and Lifestyle Factors

• Nonadherence with sodium restriction is implicated in 22% of exacerbations 3
• Excessive fluid intake precipitates acute decompensation 1
• Excessive alcohol intake causes direct myocardial toxicity 1
• Illicit drug use (cocaine, methamphetamine) 1

Infectious and Metabolic Causes

Infections

• Pulmonary infections (pneumonia, viral illnesses) increase metabolic demands and add hypoxia, associated with worse outcomes 1
• Sepsis syndrome causes reversible myocardial depression mediated by cytokine release 1
• Concurrent infections lower the threshold for admission 1

Endocrine Abnormalities

• Uncontrolled diabetes mellitus 1
• Hyperthyroidism or hypothyroidism (particularly in amiodarone-treated patients) 1
• Restoration of normal thyroid function may reverse abnormal cardiovascular function 1

Thromboembolic Events

• Pulmonary embolus should be considered as patients with HF are hypercoagulable 1
• Deep venous thrombosis may present with peripheral edema mimicking volume overload 4

Renal Dysfunction

• Deterioration of renal function can be both a consequence and contributor to decompensated HF 1
• Worsening renal function creates a vicious cycle of fluid retention and decreased diuretic responsiveness 1

Additional Cardiovascular Disorders

• Acute valve disease or endocarditis 1
• Myopericarditis 1
• Aortic dissection 1
• Cerebrovascular events 1

Comorbid Conditions

• Newly diagnosed anemia lowers threshold for admission 1
• Noncardiac conditions such as pneumonia when superimposed on CHF 1
• Multiple comorbidities (coronary disease, hypertension, valvular disease, diabetes, thromboembolism) are more common in real-world patients than clinical trials 1

Critical Clinical Pearls

• In 20% of cases, noncardiac causes (notably pulmonary infectious processes) precipitate exacerbations 3
• The precipitating event leading to hospitalization is not always readily apparent despite systematic evaluation 1
• Multiple precipitants often coexist in the same patient, requiring comprehensive assessment 1
• Many precipitating factors are avoidable through patient education and attention to medication adherence 3