Preserved vs. Reduced Ejection Fraction: Not Equivalent to Diastolic vs. Systolic Heart Failure
The terms "preserved ejection fraction" (HFpEF) and "reduced ejection fraction" (HFrEF) are NOT equivalent to "diastolic" and "systolic" heart failure, and the older terminology should be abandoned. 1
Why the Old Terms Are Misleading
The distinction between "systolic" and "diastolic" heart failure is arbitrary and clinically inaccurate because:
Most patients have both abnormalities: The vast majority of heart failure patients demonstrate evidence of both systolic AND diastolic dysfunction at rest or during exercise, making the dichotomy artificial. 1
The terms are not mutually exclusive: Patients with reduced ejection fraction have diastolic dysfunction, and patients with preserved ejection fraction often have subtle systolic abnormalities (such as reduced global longitudinal strain). 1, 2
EF primarily reflects ventricular geometry, not pure systolic function: Ejection fraction below 40% distinguishes large (dilated) versus normal left ventricular end-diastolic volumes rather than purely measuring contractility. 1
Current Recommended Classification
Modern guidelines classify heart failure by ejection fraction measurement, not by presumed mechanism: 1
- HFrEF (Heart Failure with Reduced EF): LVEF ≤40% 1
- HFmrEF (Heart Failure with Mildly Reduced EF): LVEF 41-49% 1
- HFpEF (Heart Failure with Preserved EF): LVEF ≥50% 1
What the Terms Actually Mean
HFrEF (Previously Called "Systolic HF")
- Characterized by dilated left ventricle with large end-diastolic volumes 1
- Impaired forward pumping leads to decreased cardiac output and compensatory neurohormonal activation 2
- Evidence-based therapies (ACE inhibitors, beta-blockers, SGLT2 inhibitors) have proven mortality benefit 1, 2
HFpEF (Previously Called "Diastolic HF")
- Normal or near-normal LVEF (≥50%) with symptoms/signs of heart failure 1
- Requires additional diagnostic criteria beyond EF: elevated natriuretic peptides AND/OR objective evidence of elevated LV filling pressures (by echocardiography or invasive hemodynamics) 1
- Impaired ventricular filling from reduced relaxation or compliance elevates filling pressures, causing pulmonary congestion despite preserved systolic function 2
- Represents approximately 50% of all heart failure cases 1
Critical Clinical Pitfalls
Do not assume HFpEF diagnosis based solely on symptoms plus EF ≥50%: The diagnosis requires objective evidence of cardiac dysfunction (elevated natriuretic peptides, echocardiographic evidence of diastolic dysfunction, or invasively measured elevated filling pressures) to distinguish from non-cardiac causes of dyspnea. 1
Avoid using outdated terminology in clinical documentation: Terms like "diastolic heart failure," "systolic heart failure," and "congestive heart failure" should no longer be used, as they oversimplify the pathophysiology and may lead to inappropriate treatment decisions. 1, 3
Recognize that treatment strategies differ fundamentally: Therapies proven effective in HFrEF (ACE inhibitors, beta-blockers as mortality-reducing agents) have not shown similar mortality benefits in HFpEF, where management focuses on symptom control, comorbidity management, and SGLT2 inhibitors. 1, 2, 4