What does an EF of 55-60% with an LVOT VTI of 15.5 indicate?

Understanding LVOT VTI of 15.5 with Normal EF of 55-60%

A left ventricular outflow tract (LVOT) velocity time integral (VTI) of 15.5 cm with a normal ejection fraction (EF) of 55-60% indicates borderline cardiac output that may represent early diastolic dysfunction despite preserved systolic function.

Interpretation of These Values

• An EF of 55-60% represents normal left ventricular systolic function, as normal LVEF is considered >55% for men and >57% for women 1
• An LVOT VTI of 15.5 cm is at the borderline of normal values, as LVOT VTI <15 cm is generally considered reduced 1
• This combination suggests preserved systolic function but potentially reduced stroke volume, which may indicate early diastolic dysfunction with normal ejection fraction 2

Clinical Significance

• LVOT VTI is a measure of cardiac systolic function and cardiac output that may detect subtle hemodynamic changes before EF decreases 3
• Low LVOT VTI values predict adverse outcomes in various cardiac conditions, even when EF is preserved 4
• This pattern (normal EF with borderline low VTI) may represent an early stage of heart failure with preserved ejection fraction (HFpEF) 2

Potential Mechanisms

• Diastolic dysfunction can cause reduced stroke volume despite normal ejection fraction 2
• Early stages of cardiomyopathy may present with normal EF but reduced forward flow 1
• Valvular heart disease, particularly mild to moderate aortic regurgitation, can present with this pattern 1
• Volume status alterations can affect LVOT VTI while EF remains preserved 5

Differential Diagnosis

• Early diastolic dysfunction with preserved EF 2
• Mild valvular heart disease, particularly aortic regurgitation 1
• Early transition from HFpEF to heart failure with mildly reduced EF 6
• Early septic cardiomyopathy with preserved EF but reduced stroke volume 5
• Pulmonary embolism affecting right ventricular function and consequently left ventricular filling 7

Clinical Implications

• This finding warrants further evaluation of diastolic function parameters including E/e' ratio, left atrial volume, and mitral inflow patterns 2
• Patients with borderline LVOT VTI values (15-17 cm) have higher risk of adverse cardiac outcomes compared to those with higher values 4, 3
• An EF of 55% specifically has been identified as a cutoff that may predict later transition to heart failure with mildly reduced EF 6

Recommended Follow-up

• Complete assessment of diastolic function parameters 2
• Serial echocardiographic monitoring to assess for progression 6
• Evaluation for potential underlying causes including hypertension, coronary artery disease, or valvular disease 2
• Assessment of clinical symptoms including exertional dyspnea or decreased exercise tolerance 1

Common Pitfalls

• Relying solely on EF for cardiac function assessment may miss early cardiac dysfunction 3
• Technical factors in LVOT VTI measurement (angle of insonation, sample volume placement) can affect accuracy 1
• Transient changes in loading conditions can alter LVOT VTI without indicating true cardiac dysfunction 2
• Different vendor equipment may yield slightly different LVOT VTI values 1