OpenHealth Q&A

Seeking Insights from Cardiologists on Invasive Exercise Test Findings

I’m reaching out in the hope that a cardiologist or a healthcare expert can assist me with the interpretation of my recent invasive cardiopulmonary exercise test, which included right heart catheterization. For several years, I have been coping with debilitating symptoms such as breathlessness, poor exercise tolerance, muscle fatigue, orthostatic issues, and recently, hypotension after meals. My daily life is significantly affected, and I often find myself needing to use a wheelchair. Unfortunately, the only diagnosis provided to me thus far has been ‘deconditioning’, which does not begin to account for the intensity or nature of my symptoms. The central question that remains unclear to me is this: Although my pulmonary capillary wedge pressure (PCWP) and right atrial pressure (RAP) readings appear normal both at rest and during exercise, both my cardiac output and cardiac index are remarkably high at the baseline and during physical activity. The increase in stroke volume is minimal, with the rise in cardiac output primarily due to a heightened heart rate, which points to a potential preload failure. Research indicates that: "With inadequate preload, the stroke volume quickly plateaus and any further increase in cardiac output is due to an elevation in heart rate." This aligns perfectly with what my hemodynamic data reflects. Additionally, my upright PCWP measures a mere 5 mmHg, indicating a state of preload deficiency, although I was adequately hydrated prior to the test, which might have concealed further declines in this measure. Here are some key symptoms I am experiencing: - Shortness of breath that worsens with changes in posture and during meals (e.g., lying on my side exacerbates hypotension) - Muscle fatigue and burning sensations triggered by minimal exertion - A rapid increase in heart rate with exertion, despite already elevated cardiac output at rest - Notable decline following administration of Fludrocortisone, which resulted in acute decompensation - Absence of congestion - Normal results from MRI, echocardiogram, and blood analyses (like BNP) Prominent abnormalities noted in my tests include: - Increased cardiac output at rest and during exercise - Persistent low-normal PCWP, with a drop when standing - Compromised stroke volume reserve - Low oxygen uptake efficiency slope (OUES) of 1635 (with normal being greater than 3599) - Elevated ventilatory equivalents for carbon dioxide (VE/VCO₂ slope) at 31 - Suboptimal VO₂ response despite significant effort (respiratory exchange ratio greater than 1.2, peak heart rate exceeding 100%) - Indications of impaired peripheral oxygen extraction as suggested by VO₂/HR and dCO/dVO₂ slope This situation appears to reflect a form of preload failure accompanied by high-output physiology, perhaps signaling early or masked heart failure with preserved ejection fraction (HFpEF) or an issue with autonomic regulation of circulation. I’ve come across literature on similar presentations related to preload deficiency and high-output scenarios but have yet to engage a specialist who is willing to take my concerns seriously. Could this be classified as a type of heart failure? Why does it not fit the criteria for high-output heart failure or preload failure? Your thoughts would be immensely valuable; this journey has been profoundly challenging, and I am eager for explanations that resonate with my physiological experiences. I am a 45-year-old male with a history of Sick Sinus Syndrome and a pacemaker, in addition to obesity, MASLD, and low testosterone levels.

Answers (1)

7/2/2025, 5:31:07 PM

OpenHealth AI

It sounds like you have gone through an extensive and frustrating journey with your symptoms, and it's commendable how you're actively seeking clarity regarding your condition. Based on the findings you provided from your cardiopulmonary exercise test and your ongoing symptoms, it does seem you're facing a complex situation.

Main Points:

Your abnormal test results, notably high cardiac output with low stroke volume reserve, suggest issues that may not fit neatly into typical heart failure categories. It might indicate a form of cardiovascular dysregulation, possibly linked to preload failure, rather than classic high-output heart failure.

Explanation:

1. Pulmonary Capillary Wedge Pressure (PCWP): Your low-normal PCWP suggests that your heart isn't receiving enough blood return (preload), which is crucial for maintaining stroke volume and cardiac output during exercise. This might explain your experience of breathlessness and fatigue.

2. High Cardiac Output with Low Stroke Volume Reserve: The fact that your cardiac output is high primarily due to an increased heart rate indicates that your heart struggles to pump effectively under stress, relying on heart rate instead of stroke volume to meet oxygen demands during physical activity.

3. Autonomic Regulation: Your symptoms and test results may reflect an issue with how your autonomic nervous system regulates your cardiovascular function, which can lead to symptoms like hypotension after meals and orthostatic issues.

4. Context of Existing Health Conditions: Conditions such as obesity, sick sinus syndrome, and low testosterone levels may complicate your cardiovascular function and contribute to your symptoms.

Next Steps:

1. Symptom Tracking: Keep a detailed diary of your symptoms, noting specific triggers (like posture changes and meals) alongside times of day when symptoms worsen. This information can help specialists understand your condition better.

2. Fluid Management: Since you mentioned hydration issues, ensure you drink enough fluids throughout the day. Discuss with a healthcare professional or dietitian about potential dietary changes that could aid in managing your symptoms, such as smaller, more frequent meals to avoid postprandial hypotension.

3. Autonomic Testing: Ask about further evaluation for autonomic function, which may include tilt table testing or other assessments to understand how your body regulates blood flow and heart rate when changing positions.

4. Specialist Consultation: If you haven’t yet, consider seeking a consultation with a cardiologist who specializes in heart failure or autonomic disorders. They might be more attuned to cases like yours and could provide further insights or treatment options.

5. Physical Activity and Rehabilitation: Engage in a gentle exercise program, possibly tailored through cardiac rehabilitation, focusing on building endurance without overstraining your heart. Listen to your body regarding activity levels.

While your symptoms warrant serious attention, it's important to approach them systematically to build a comprehensive understanding and management plan. Please remember that while navigating your healthcare journey can be challenging, you are advocating for your health, and that's incredibly important.