5. Diagnosis of HF
5.1 General considerations
HF is a complex clinical syndrome in which abnormal heart function results in, or increases the subsequent risk of, clinical symptoms and signs of reduced cardiac output and/or pulmonary or systemic congestion at rest or with stress. The cardinal triad of edema, fatigue, and dyspnea is not a sensitive or a specific manifestation of HF, and atypical presentations should be recognized, particularly when evaluating women, obese patients, and elderly patients (Table 4). A thorough clinical history and physical examination should be performed in all patients, and initial investigations should be targeted to confirm or exclude HF as the diagnosis as well as to identify systemic disorders (eg, thyroid dysfunction) that might affect its development or progression (Fig. 1, Table 5). Measurement of plasma NPs is helpful because low concentrations are very useful in excluding HF and high concentrations can confirm HF in patients who present with dyspnea when the clinical diagnosis remains uncertain.
Two-dimensional and Doppler transthoracic echocardiography are the initial imaging modalities of choice in patients suspected to have HF because they are used to assess systolic and diastolic ventricular function, wall thickness, chamber sizes, valvular function, and pericardial disease. Contrast echocardiography or radionuclide angiography might be useful in patients in whom echocardiographic images are poor. Cardiac catheterization with hemodynamic measurements and contrast ventriculography, computed tomography (CT), and CMR imaging can be used when other noninvasive tests are inconclusive and might be required for specific cardiomyopathies (see the section 7.5.1. Cardiomyopathies and Figs. 1 and 2).
15. We recommend the choice of investigations should first be guided by careful history and physical examination and when clinical evidence suggests a possible cause and the planned test(s) result(s) would be reasonably expected to lead to a change in clinical care (Strong Recommendation; Low-Quality Evidence).
16. We recommend that a 12-lead electrocardiogram (ECG) be performed to determine heart rhythm, heart rate, QRS duration, and morphology, and to detect possible etiologies (Strong Recommendation; Low-Quality Evidence).
17. We recommend that echocardiography be performed in all patients with suspected HF to assess cardiac structure and function, to quantify systolic function for planning and monitoring of treatment, and for prognostic stratification (Strong Recommendation; Moderate-Quality Evidence).
18. We recommend that cardiac magnetic resonance (CMR) imaging might be used when echocardiographic imaging (including contrast echocardiography) is nondiagnostic, or help to elucidate the etiologies (eg, myocarditis) (Strong Recommendation; Low-Quality Evidence).
19. We recommend that in a patient suspected to have a cardiomyopathy, an inquiry should be made regarding family history, concomitant illnesses, previous malignancy requiring radiation or chemotherapy, symptoms of hypo- or hyperthyroidism, pheochromocytoma, acromegaly, previous travel, occupational exposure to chemicals or heavy metals, nutritional status, alternative medicine or naturopathic agents, illicit drug use, and exposure to HIV (Tables 6-8) (Strong Recommendation; Low-Quality Evidence).
20. We recommend that tachycardia-induced cardiomyopathy should be suspected when LVSD, with or without typical HF signs or symptoms, occurs with a persistent inappropriate tachycardia or tachyarrhythmia without another identified cause for the heart dysfunction (Strong Recommendation; Low-Quality Evidence).
Patients might have HF even without a history or current evidence of volume overload.
An imaging-based assessment (typically with echocardiography) of valvular abnormalities should be done early in the diagnosis of HF.
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