Investigations
Allows for the accurate determination of biventricular systolic and diastolic function. With systolic heart failure, echo usually demonstrates a dilated left and/or right ventricle with low ejection fraction. With pure diastolic heart failure left ventricular ejection fraction (LVEF) is normal but there is evidence of left ventricular hypertrophy (LVH) and of abnormal diastolic filling patterns on Doppler evaluation. Echocardiogram can also identify valvular, myocardial, or pericardial disease or may reveal evidence of underlying coronary artery disease (regional wall motion/thickness abnormalities). A hypertrophied heart may be due to hypertension, hypertrophic obstructive cardiomyopathy, or infiltrative disease like amyloidosis. It should be performed in every patient presenting with heart failure symptoms.
systolic heart failure: depressed and dilated left and/or right ventricle with low ejection fraction; diastolic heart failure: LVEF normal but LVH and abnormal diastolic filling patterns
QRS duration above 120 ms should always raise the question of ventricular dyssynchrony.
evidence of underlying coronary artery disease, left ventricular hypertrophy, or atrial enlargement; may be conduction abnormalities and abnormal QRS duration
May reveal pulmonary vascular congestion (vascular redistribution, Kerley B lines), cardiomegaly (increased cardiothoracic ratio), or pleural effusion (usually right-sided but often bilateral).
abnormal
Elevated plasma BNP levels have been associated with reduced left ventricular ejection fraction,[83] left ventricular hypertrophy, elevated left ventricular filling pressures, and acute myocardial infarction and ischaemia, although they can occur in other settings, such as pulmonary embolism and chronic obstructive pulmonary disease.[83][84][85] They are sensitive to other biological factors, such as age, sex, weight, and renal function. Elevated levels lend support to a diagnosis of abnormal ventricular function or haemodynamics causing symptomatic heart failure.[86][87][88] A low plasma BNP level (<100 nanograms/L or <100 picograms/mL) can rapidly rule out decompensated heart failure and point to a pulmonary cause. A high plasma BNP level (>400 nanograms/L or >400 picograms/mL) strongly supports the diagnosis of abnormal ventricular function (i.e., heart failure). Intermediate values (100 to 400 nanograms/L or 100 to 400 picograms/mL) fall into the so-called 'grey zone' and should spur a search for a potential non-cardiac cause of dyspnoea: for example, COPD. In patients presenting with dyspnoea, measurement of natriuretic peptide biomarkers is useful to support a diagnosis or exclude heart failure. However, elevated plasma levels of natriuretic peptides can occur with a wide variety of cardiac and non-cardiac causes; therefore, clinical judgement is necessary.[80]
Trials with this diagnostic marker suggest that its use may reduce both the time to hospital discharge and the cost of treatment.[89][90][91] BNP levels tend to be less elevated in heart failure with preserved ejection fraction than in heart failure with low ejection fraction and are lower in obese patients.[92] Levels of BNP may be elevated meaningfully in women and in people over 60 years of age who do not have heart failure, and thus BNP levels should be interpreted cautiously in such individuals.[73][93][94]
elevated
Anaemia and high lymphocyte percentage are strong risk factors and prognostic markers of poor survival.
laboratory testing may reveal important heart failure aetiologies, the presence of disorders or conditions that can lead to or exacerbate heart failure; laboratory testing could also reveal important modulators of therapy
Baseline electrolytes should be obtained in all patients.
decreased sodium (usually <135 millimols/L), altered potassium
Reflects tissue perfusion, fluid status, rules out renal disease.
normal to elevated
Reflects abdominal congestion.
normal to elevated
Screening for hypo- or hyperthyroidism. Both can be a primary or contributory cause of heart failure.
primary hypothyroidism: elevated TSH, decreased free thyroxine (FT4); hyperthyroidism: decreased TSH, elevated free triiodothyronine, elevated FT4
Screening for dyslipoproteinaemias/metabolic syndrome.
elevated in dyslipidaemia, decreased in end-stage heart failure, especially in the presence of cardiac cachexia
For evaluation of cardiomyopathy due to iron overload cardiomyopathy/haemochromatosis.
elevated (normal value 22-449 picomol/L [10-200 nanograms/mL])
For evaluation of cardiomyopathy due to iron overload cardiomyopathy/haemochromatosis.
elevated level of transferrin saturation; complete or almost complete transferrin saturation (normal transferrin saturation 22% to 46%)
To detect myocardial ischaemia and viability when underlying ischaemic heart disease is suspected.
ischaemia, scar, viable myocardium
Provides an objective assessment of the patient's functional exercise limitation and haemodynamic response to exercise. Test is ordered when exercise-induced arrhythmias or ischaemia are suspected. Caution should be taken if there is a high likelihood for aortic stenosis or hypertrophic obstructive cardiomyopathy.
usually reduced exercise capacity in idiopathic dilated cardiomyopathy; reduced exercise capacity and signs of impaired myocardial perfusion in ischaemic cardiomyopathy; however, functional capacity may be completely normal in patients with low left ventricular systolic function
Provides assessment of coronary stenosis, and is particularly indicated in patients with heart failure and angina, ventricular tachycardia, or cardiac arrest. It is also done in patients with heart failure and ischaemia on non-invasive stress test.
coronary artery disease/stenosis
Its main use is in patients with heart failure who have low or intermediate pre-test probability of underlying coronary artery disease, or those with equivocal non-invasive stress tests.
In clinical practice it is also useful in patients with a clinical picture of stress/Takotsubo cardiomyopathy, in whom significant proximal coronary artery disease needs to be excluded as a cause of underlying presentation and echocardiogram findings.
coronary artery disease/stenosis
Provides the most objective assessment of the patient's functional status.
reduced VO₂ max
A patient with heart failure who cannot walk more than 300 m in 6 minutes has a substantially greater annual risk of death than one who can walk 450 m or more.
as an alternative to cardiopulmonary exercise testing it may provide an objective assessment of the patient's functional status
Considered in patients intolerant to standard medical therapy, in whom medical therapy has failed to achieve symptomatic relief, before initiation of IV inotrope or inodilator therapy and in candidates for heart transplantation.
provides objective haemodynamic assessment of left ventricular filling pressure and direct measures of cardiac output and pulmonary and systemic resistance
Ordered if acute myocarditis (giant cell or eosinophilic) or primary infiltrative diseases of the heart (amyloidosis, active cardiac sarcoidosis) suspected.
rarely necessary to establish the aetiology of heart failure; provides definitive pathological evidence of cardiac and systemic disease
The majority of patients who have cardiomyopathy due to HIV do not present with symptoms of heart failure until other clinical signs of HIV infection are apparent.
positive or negative
Particularly useful in evaluation of conditions like myocarditis, constrictive pericarditis, and infiltrative cardiomyopathy.
myocarditis: sub-epicardial delayed enhancement in myocardium, high signal in myocardium in T2-weighted imaging; infiltrative cardiomyopathy: amyloid (global sub-endocardial delayed enhancement); sarcoid: (delayed enhancement); no sub-endocardial delayed enhancement; constrictive pericarditis: thick pericardium as well as diastolic septal bounce with inspiration
Troponin is helpful in further risk stratification in chronic heart failure, as elevated level is associated with progressive left ventricular dysfunction and increased mortality.[2][81]
Soluble ST2 and galectin-3 (biomarkers for myocardial fibrosis) are predictive of death and hospitalisation in patients with heart failure and are additive to natriuretic peptide in their prognostic value.[2]
borderline to minimally elevated
A method for left ventricular ejection fraction (LVEF) estimation. There appears to be no significant difference in LVEF estimation between MSCT and MRI, and also between MSCT and transthoracic echocardiogram.[95]
May offer additional benefit as it provides a combined evaluation of LVEF and coronary artery disease.
quantifies LVEF and coronary artery disease
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