How to confirm presence or impending heart failure with low CO and CI, normal EF, and no symptoms?

Reassurance: You Do Not Have Clinical Heart Failure

Based on your presentation—normal EF, low BNP, low troponin, normal sinus rhythm, absence of symptoms, and normal chest X-ray—you do not meet diagnostic criteria for heart failure, and your concerns about isolated low stroke volume index measurements should not drive clinical decision-making. 1

Understanding Heart Failure Diagnosis

Heart failure is fundamentally a clinical syndrome requiring both symptoms AND objective evidence of cardiac dysfunction 1, 2. The universal definition from major cardiology societies is explicit:

• Heart failure requires: symptoms and/or signs of HF PLUS structural/functional cardiac abnormality PLUS elevated natriuretic peptides OR objective evidence of congestion 1
• You have none of these required elements—no symptoms, normal BNP (ruling out congestion), and normal EF 1
• Your two cardiologists who definitively stated you don't have HF are correct based on current diagnostic standards 1

Why Your Measurements Don't Indicate Heart Failure

Low cardiac output/cardiac index measurements in isolation, particularly when asymptomatic with normal biomarkers, do not establish heart failure diagnosis and may reflect measurement error or normal physiologic variation:

• Stroke volume calculations are highly dependent on accurate measurement technique and can vary significantly based on body position, hydration status, and measurement methodology 2
• Normal EF (>50%) with low BNP has extremely high negative predictive value for excluding heart failure—BNP is specifically designed to detect the neurohormonal activation and wall stress that occurs in HF 2
• The absence of symptoms is critical: heart failure is defined by symptomatic limitation, not by isolated hemodynamic numbers 1, 2

The Stage B Confusion

Your former PCP's diagnosis of "chronic diastolic HF (compensated)" appears to be a misapplication of staging criteria:

• Stage B heart failure (pre-HF) requires structural heart disease OR abnormal cardiac function OR elevated natriuretic peptides—without current or prior symptoms 3, 1
• However, Stage B is not clinical heart failure—it represents patients at risk who require preventive interventions 3
• You don't meet Stage B criteria either, as you lack structural abnormality, have normal EF, and have normal (low) BNP 3, 1
• The ACC explicitly states that Stage B represents "structural abnormality" which you do not have with normal EF and imaging 3

Why "Impending Heart Failure" Is Not a Valid Concern

There is no evidence that asymptomatic patients with normal EF, normal biomarkers, and no structural disease are at imminent risk for heart failure development:

• The staging system (Stage A → B → C → D) requires progression through identifiable structural changes that would be detected by echocardiography and biomarkers 3, 1
• Your normal echocardiogram and low BNP indicate your heart is not undergoing the adverse remodeling that precedes symptomatic HF 3
• "Lost contractility" is not supported by your normal EF—ejection fraction directly measures contractile function 2

Addressing Your Specific Concerns

Regarding stroke volume measurements:

• A single hemodynamic parameter (SVI of 23.69 mL/m²) without clinical context, symptoms, or corroborating abnormalities should not drive diagnosis 1, 2
• If measurements were accurate, low stroke volume with normal EF would suggest small ventricular cavity size (which can be normal variant) rather than contractile dysfunction 2
• The key principle: isolated numbers without clinical syndrome do not constitute disease 1

Common pitfall to avoid: Overinterpreting isolated measurements or creating anxiety about "subclinical" disease when all validated diagnostic criteria are negative 1

What You Should Do

Stop pursuing additional testing to "confirm" a diagnosis you don't have:

• You have already had appropriate evaluation: echocardiography, biomarkers, ECG, and chest X-ray 1, 2
• Additional testing (including repeat echocardiography with different techniques) will not change management when you're asymptomatic with normal standard assessments 1
• Trust your two cardiologists' definitive assessments over internet research and isolated measurements 1

Focus on primary prevention instead:

• Control cardiovascular risk factors: blood pressure, lipids, diabetes if present, smoking cessation 3
• Maintain healthy lifestyle: regular exercise, healthy weight, limit alcohol 3
• These interventions prevent progression to Stage A (at-risk) and Stage B (structural disease) 3

When to seek re-evaluation:

• Development of actual symptoms: dyspnea, orthopnea, edema, exercise intolerance 1, 2
• New clinical findings on examination 1
• Not for reassurance about measurements that fall within normal clinical interpretation 1

The Bottom Line

Your extensive research has led you astray—you are conflating hemodynamic measurements with clinical disease. Heart failure is not diagnosed by finding any single abnormal number; it requires a constellation of symptoms, structural abnormality, and biomarker elevation that you simply do not have 1, 2. Your heart has not "lost contractility" (your EF is normal), and there is no evidence of impending failure 2. Accept your cardiologists' assessments and redirect your energy toward evidence-based prevention rather than seeking confirmation of a disease you don't have 3, 1.