CMR indicates cardiac magnetic resonance; CT, computed tomography; ECG, electrocardiogram; HF, heart failure; LV, left ventricular; PET, positron emission tomography; STS, Society of Thoracic Surgeons; TAVI, transcatheter aortic valve implantation; TEE, transesophageal echocardiography; TTE, transthoracic echocardiography; and VHD, valvular heart disease. CLINICAL STATEMENTS AND GUIDELINES patients with VHD, there is still a subset of patients in whom hemodynamic catheterization is necessary to ensure that the proper decision about treatment is made. If noninvasive testing yields inconclusive data, particularly in the symptomatic patient, or if there is a discrepancy between the noninvasive tests and clinical findings, a hemodynamic cardiac cath- eterization with direct intracardiac measurements of transvalvular pressure gradients and cardiac output measurements provides valuable clinical information. Severity of stenosis may be underestimated when im- aging is difficult or when the Doppler beam is not aligned parallel to the direction of the high-velocity jet. Severity of valve regurgitation may be overesti- mated or underestimated if the image or Doppler data quality is suboptimal. Contrast angiography is sometimes useful for a semiquantitative assessment of the severity of regurgitation in those instances in which the noninvasive results are discordant with the A major advantage of cardiac catheterization is the measurement of intracardiac pressures and pulmonary vascular resistance, which may further aid in decision-making about valve intervention. Diagnostic interventions that can be performed in the catheterization laboratory include the use of dobutamine in low-flow states, pulmonary vasodilators in pulmonary hypertension, and exercise hemodynamics in patients with discrepant symp- A hemodynamic catheterization needs to be done with meticulous attention to detail by persons with knowledge and expertise in assessing patients with VHD. 2.3.5. Diagnostic Testing: Exercise Testing In a subset of patients, exercise stress testing will be of additional value in determining optimal therapy. 