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Science & Technology



Shape-HF Measures Key Ventilation Parameters


Shape-HF measures a patient’s physiology to provide objective information needed to assess functional capacity, therapy response and risk—all valuable in assessing and treating chronic heart failure and other cardiac and pulmonary diseases.


The Shape-HF system measures key ventilation parameters that help doctors pinpoint the source of dyspnea limitation as being predominantly heart or lung.  These parameters provide a continuum of functional values that improve sensitivity of the assessment and add physiological resolution to the New York Heart Failure Association classification system.


Specifically, Shape-HF measures ventilatory efficiency, oxygen uptake efficiency, CO2, heart rate recovery, and chronotropic response index.


Ventilatory Efficiency Slope (VE/VCO2): Ventilatory efficiency is a measure of breathing efficiency and is defined as the linear slope of the amount of air expired per minute (VE) versus the amount of carbon dioxide produced per minute (VCO2). Clinical studies have shown that ventilation efficiency is a powerful predictor of patient risk.


This parameter is particularly useful in assessing patients with heart failure, coronary artery disease or angina, and is effectively used in evaluating the physiological response to pharmaceutical or medical device intervention.


Oxygen Uptake Efficiency Slope (VO2/logVE): Oxygen uptake efficiency slope indicates the amount of oxygen that is used per unit ventilation. It is used to assess the coupling between the heart and lungs and has been identified as a significant independent predictor of patient risk.


This parameter is useful in assessing patients with heart failure, and is also effective in evaluating the physiological response to cardiac rehabilitation and pharmaceutical or medical device intervention.


Partial Pressure of End-Tidal Carbon Dioxide (PetCO2 or ETCO2): The partial pressure of end-tidal CO2 reflects the concentration of CO2  in the alveoli at the end of expiration. PetCO2 is a correlate of cardiac output. As cardiac output increases, so does the concentration of expired CO2 both at rest and during exercise.


The measure of PetCO2 is useful in heart failure assessment, pulmonary hypertension assessment and in evaluating patient response to pharmaceutical or medical device therapy.


Heart Rate Recovery (from exercise): The decay in heart rate over the first minute of exercise recovery relates to the degree of sympathetic activation and parasympathetic reactivation following exercise. This parameter is useful in assessing patients with heart failure, coronary artery disease and angina. It is effectively used in evaluating the physiological response to cardiac rehabilitation and pharmaceutical or medical device intervention.


Chronotropic Response Index (CRI): Chronotropic response index (CRI) is a measure of the patient's heart rate response to dynamic exercise. Clinical studies have shown that CRI is a significant independent risk factor for all-cause and cardiovascular death in individuals with or without known or suspected coronary artery disease.


The chronotropic response index is a parameter for use in patients with ischemic heart disease or heart failure, and provides a useful physiological parameter in assessing pharmaceutical and medical device intervention or cardiac rehabilitation.






“Ventilatory gas exchange analysis during exercise testing is a useful adjunmctive tool in assessment of patients with cardiovascular and pulmonary disease.”


ACC/AHA Guideline Update for Exercise Testing
2002
ACC website