Introduction: Cardiopulmonary exercise testing (CPET) is an exercise test that integrally evaluates cardiovascular, respiratory, and metabolic responses to physical effort, allowing an accurate assessment of functional capacity and ventilatory efficiency. It is characterized by high sensitivity and specificity, as well as the ability to detect myocardial ischemic alterations at an early stage, even before they become evident through conventional imaging techniques. In this context, its application during cardiac rehabilitation programs may provide relevant information for the diagnosis and safe management of patients with suspected coronary microvascular disease. The aim of this clinical case is to highlight the usefulness and feasibility of CPET for the early detection of microvascular ischemia in the setting of cardiac rehabilitation.
Clinical observation: We present the case of a 54-year-old woman referred to cardiac rehabilitation with a diagnosis of non-obstructive apical hypertrophic cardiomyopathy and recurrent atrial fibrillation. The patient reported dyspnea with mild exertion, corresponding to New York Heart Association (NYHA) functional class III, as well as occasional chest pain. An initial evaluation using CPET revealed severe functional limitation, classified as Weber class C, together with significant ventilatory impairment (Arena class 4), which justified the indication for a structured cardiac rehabilitation program. After completion of the program, a repeat CPET demonstrated objective criteria of myocardial ischemia according to Belardinelli.
Conclusions: This case highlights the usefulness of CPET for the early detection of microvascular myocardial ischemia in patients without a prior diagnosis based on conventional testing. Moreover, CPET is reinforced as a fundamental tool for designing individualized training programs, optimizing functional capacity, and ensuring patient safety during cardiac rehabilitation.