Can cardiogenic shock be present with a normal Ejection Fraction (EF) on echocardiography?

Can Cardiogenic Shock Present with Normal EF on Echo?

Yes, cardiogenic shock can absolutely occur with preserved or normal left ventricular ejection fraction, and recognizing this is critical to avoid missing life-threatening causes that require immediate intervention. 1, 2

Key Mechanisms of Cardiogenic Shock with Normal EF

While severe LV systolic dysfunction remains the most common cause of cardiogenic shock, multiple etiologies can produce shock despite preserved LVEF:

Right Ventricular Infarction

• RV infarction is a classic cause of cardiogenic shock with normal or near-normal LVEF, most commonly associated with inferior MI. 1
• The LV may appear relatively unloaded and can have preserved or even hyperdynamic function because the failing RV cannot deliver adequate preload to the left heart. 1
• Echo findings include: RV dyssynergy, RV dilatation, paradoxical septal motion, McConnell sign, decreased TAPSE, and tricuspid regurgitation with low pulmonary pressures. 1

Mechanical Complications of AMI

• Acute severe mitral regurgitation (from papillary muscle rupture or dysfunction) can cause shock with preserved LVEF because the ventricle ejects into the low-resistance left atrium rather than the aorta. 1
• Ventricular septal rupture creates a left-to-right shunt, reducing forward cardiac output despite normal contractility. 1
• Free wall rupture with tamponade physiology can present with shock and normal ventricular function. 1

Severe Valvular Disease

• Acute severe aortic stenosis, acute aortic regurgitation, or acute mitral regurgitation can cause cardiogenic shock with preserved systolic function. 1

Diastolic Dysfunction

• Patients with severe diastolic heart failure (heart failure with preserved ejection fraction) can develop cardiogenic shock, particularly when precipitated by acute ischemia, arrhythmias, or volume overload. 2
• The pathophysiology involves severely elevated filling pressures despite normal contractility, leading to pulmonary edema and reduced cardiac output. 2

Other Causes

• Cardiac tamponade, myocarditis, myocardial contusion, and acute aortic dissection can all present with shock and preserved LVEF. 1

Critical Diagnostic Approach

Immediate Echocardiography is Mandatory

• Echo is the most valuable initial diagnostic tool and should be performed immediately in all suspected cardiogenic shock patients. 1, 3, 4
• The European Heart Journal explicitly states that normal LV and RV systolic function, normal chamber dimensions, absence of significant valvular pathology, and absence of pericardial effusion virtually rule out a cardiac cause of shock. 4

Key Echo Parameters Beyond LVEF

When LVEF is preserved, focus on:

• RV function assessment: TAPSE, RV size, septal motion, McConnell sign 1
• Valvular function: Look for acute severe MR, VSD, or other mechanical complications 1
• Pericardial space: Rule out tamponade 1
• LVOT VTI (velocity-time integral): This reflects forward flow and is a critical prognostic marker that may be more important than LVEF alone 5
• Diastolic function: Elevated filling pressures with preserved EF 2
• Stroke volume and cardiac output: Can be severely reduced despite normal EF 1

Clinical Pitfalls to Avoid

Don't Be Falsely Reassured by Normal LVEF

• A normal ejection fraction does NOT exclude cardiogenic shock. 2, 6
• The concept of "normal ejection fraction, low cardiac output cardiogenic shock" is well-established, where reporting LVEF in isolation can be dangerously misleading. 6

Consider Ventricular Cavity Size

• In cases like post-VSD repair, the residual functional LV cavity may be too small to maintain adequate cardiac output despite normal contractility. 6
• Small LV cavity with hyperdynamic function may indicate severe hypovolemia or RV failure with underfilling of the LV. 1

Look Beyond the Left Ventricle

• RV function is frequently overlooked but is a critical cause of shock with preserved LVEF. 1
• Assessment of LV function in the context of acute severe RV dysfunction can be challenging because the LV may be relatively unloaded. 1

Hemodynamic Monitoring May Be Necessary

• When echo findings are equivocal or don't match the clinical picture, invasive hemodynamic monitoring with pulmonary artery catheterization should be considered. 3
• This can definitively establish elevated filling pressures (PCWP >15-20 mmHg) with reduced cardiac index (<2.2 L/min/m²) despite preserved LVEF. 3, 7

Prognostic Considerations

• The prognosis of acute cardiogenic shock with preserved EF is actually very favorable provided prompt diagnosis and appropriate treatment are instituted. 2
• This contrasts with reduced EF cardiogenic shock and emphasizes the importance of correct diagnosis, as therapeutic approaches differ significantly. 2
• LVOT VTI has emerged as potentially the single best predictor of hospital mortality in cardiogenic shock patients, outperforming LVEF alone. 5