What is the initial test to diagnose chronic heart failure in a patient?

Initial Test for Chronic Heart Failure Diagnosis

The electrocardiogram (EKG/ECG) is the initial test to screen for chronic heart failure, as a normal ECG has a negative predictive value exceeding 90% to exclude left ventricular systolic dysfunction, making heart failure unlikely. 1

Diagnostic Algorithm

First-Line Screening: ECG

• An ECG should be obtained first in all patients with suspected chronic heart failure 1, 2
• A completely normal ECG suggests the diagnosis of chronic heart failure should be carefully reviewed, as heart failure (especially due to LV systolic dysfunction) is unlikely 1
• The negative predictive value of a normal ECG to exclude LV systolic dysfunction exceeds 90% 1
• An abnormal ECG has little predictive value for the presence of heart failure, but a normal one effectively rules it out 1

Second-Line Testing: Natriuretic Peptides

• If the ECG is abnormal or clinical suspicion remains high, NT-proBNP or BNP should be measured next 1, 2
• Natriuretic peptides are most useful as a "rule out" test due to their consistently high negative predictive values 1
• A low-normal concentration in an untreated patient makes heart failure unlikely as the cause of symptoms 1
• NT-proBNP and BNP are helpful in the diagnostic process, especially in untreated patients 1

Definitive Diagnosis: Echocardiography

• Echocardiography is required to confirm the diagnosis, as objective evidence of cardiac dysfunction at rest is necessary 1
• Echocardiography is the preferred method for documenting cardiac dysfunction 1
• The most important parameter is the LV ejection fraction for distinguishing systolic dysfunction from preserved systolic function 1
• Echo provides assessment of valvular function, cardiac filling characteristics through Doppler, and helps determine etiology 1

Why Not the Other Options?

NT-proBNP (Option b)

• While valuable, natriuretic peptides should follow an abnormal ECG in the diagnostic sequence 1
• NT-proBNP levels can be falsely elevated in advanced age, renal dysfunction, atrial fibrillation, pulmonary hypertension, and acute pulmonary embolism 2
• NT-proBNP may be falsely low in obesity, flash pulmonary edema, and heart failure with preserved ejection fraction 2

Echocardiography (Option c)

• Echo is essential for confirming the diagnosis but is not the initial screening test 1
• It should be performed after ECG and/or natriuretic peptide testing suggest cardiac dysfunction 1

TEE (Option d)

• Transesophageal echocardiography is not recommended routinely 1
• TEE is only indicated for inadequate echo windows, complicated valvular patients, suspected mechanical valve dysfunction, or when identifying/excluding atrial appendage thrombus 1

Critical Pitfalls to Avoid

• Do not skip the ECG: An abnormal ECG has poor specificity but a normal ECG has excellent negative predictive value 1
• Do not rely on symptoms alone: Fatigue, dyspnea, and peripheral edema are typical but not specific for heart failure 1
• Do not order echo first: This wastes resources when a simple ECG could rule out the diagnosis 1
• Remember the diagnostic triad: Clinical presentation + ECG abnormality + objective cardiac dysfunction on imaging 1