I. Symptoms and characteristics of heart failure
The symptoms of heart failure are broadly divided into three categories: dyspnea, exertional decline and fluid retention.
Respiratory distress in heart failure patients is manifested in the following order according to the degree of severity: exertional shortness of breath, high pillow position, paroxysmal nocturnal dyspnea, shortness of breath at rest, and acute pulmonary edema.
Patients with heart failure have reduced exercise tolerance, reflecting impaired cardiac reserve function. This is manifested by shortness of breath and weakness on exertion or during daily activities, and limited activity.
Fluid retention in heart failure patients may manifest as swelling, abdominal distention, and plasma cavity effusion.
Physical examination: daily weight measurement, observation of patients with jugular vein rage, symmetric depressed hypoplasia site edema, pulmonary rales, pleural effusion, heart enlargement, heart murmur, gallop rhythm, tachycardia, arrhythmia, positive hepatic neck reflux sign, hepatomegaly, ascites sign, etc.
II. Laboratory tests
(A) Imaging examination
Echocardiography and Doppler ultrasonography are the most valuable methods for diagnosing organic heart disease and evaluating cardiac function. They can comprehensively and dynamically display the heart structure including heart valves, myocardium, pericardium and blood vessels, and quantitatively and qualitatively analyze them. It is also capable of measuring cardiac function, distinguishing systolic or diastolic cardiac insufficiency, evaluating the effectiveness of treatment, and providing prognostic information. Small dose dobutamine echocardiographic stress test can be used to determine the surviving myocardium.
2.Radionuclide ventriculography and nuclide myocardial perfusion imaging Nuclide ventriculography can accurately measure left ventricular volume, ejection fraction and ventricular wall motion, and clarify whether there is left ventricular enlargement and whether there is local motion abnormality in the myocardium. Nuclear myocardial perfusion imaging can diagnose myocardial ischemia and myocardial infarction and evaluate surviving myocardium. However, it is more expensive.
3.X-ray chest X-ray provides information on heart enlargement, pulmonary stasis, pulmonary edema and pre-existing lung disease. Heart disease and heart failure cannot be ruled out if no abnormalities are seen on the chest X-ray.
4.Cardiac catheterization and coronary angiography Coronary angiography should be performed if angina pectoris or previous myocardial infarction requires revascularization or if coronary artery disease is clinically suspected.
5.Magnetic resonance imaging For patients with clinically suspected arrhythmogenic right ventricular dysplasia.
6.Positron emission tomography Evaluation of surviving myocardium before revascularization for old myocardial infarction in coronary heart disease.
(C) Electrocardiogram
Provides information on myocardial ischemia or infarction, atrial size, arrhythmias, electrolyte disturbances, pacemaker and drug interventions, and pericardial inflammation. Due to the poor specificity and sensitivity of ECG, the cause of heart disease cannot be clarified based on one ECG alone.
(iv) Laboratory tests
Patients with heart failure should have blood and urine routine, serum electrolytes, blood urea nitrogen, creatinine, blood glucose, liver function, and thyrotropin hormone tests. In some patients, blood antinuclear antibodies, rheumatoid factor, sedimentation, anti-“O”, C-reactive protein, and uric acid can be measured. Routine measurement of blood norepinephrine or endothelin concentrations is not recommended. Recently, it has been noted that brain natriuretic peptide concentration in blood may become a new biochemical indicator for the diagnosis of heart failure. ‘
(v) Hemodynamic monitoring
It is mainly used in acute heart failure (acute decompensation phase of chronic heart failure) that is seriously life-threatening and does not respond to treatment or when identifying the cause of dyspnea, hypotension, or shock.
III. Assessment of the degree of cardiac insufficiency
(A) New York Heart Association (NYHA) cardiac function classification
The NYHA classification has been familiar and accepted by the majority of doctors. Although NYHA classification is subjective and has limited accuracy and repeatability, it is still the easiest way to evaluate cardiac function.
(B) Cardiopulmonary exercise test
Cardiopulmonary exercise test is to monitor oxygen consumption (VO:), anaerobic enzymatic threshold (AT) and other gas exchange indexes at the same time of exercise test, which can evaluate the degree of cardiac insufficiency more objectively, reflect the heart reserve function in the early stage of heart failure, evaluate the treatment efficacy and provide prognostic information.
Weber classified heart failure into four classes according to peak oxygen consumption [Peak VO2 (m1/kg/min)] and AT (m1O2/kg/min). a: PVO2: >20, AT >14, no or mild cardiac insufficiency. b: PVO2: 16-20, AT ll-14, mild or moderate cardiac insufficiency. c: PVO2: 10-15, AT 8-11, moderate or severe cardiac insufficiency. 11, moderate and severe cardiac insufficiency. D: PVO2: <10< span="">, AT<8< span="">, severe cardiac insufficiency. The indication for this trial is for patients with chronic stable heart failure. Stable clinical condition lasting at least 2 weeks, including no symptoms of heart failure at rest; no postural hypotension; stable fluid balance with diuretic dose adjustment no more than once a week; stable renal function such as blood creatinine level and normal electrolytes. If blood pressure is less than 80 mmHg and heart rate is less than 50 beats/min, this test should not be done. ACC/AHA recommends cardiopulmonary exercise test for identifying the cause of exertional limitation; screening for heart transplantation or non-pharmacological treatment of high-risk groups.
(C) Six-minute walk test
Since the intensity of daily physical activity is less than the maximum exercise capacity, measuring submaximal exercise capacity will provide useful information. The six-minute walk test is a simple, easy to perform, safe and effective method that requires the patient to walk as far as possible in a hallway to determine the distance walked in six minutes. A walking distance of << span="">150 meters in six minutes indicates severe heart failure, between 150-425 meters is moderate heart failure, and 426-550 meters is mild heart failure. The results of the six-minute walk test are independent predictors of disability and mortality in heart failure, and can be used to evaluate patients’ cardiac reserve function and to evaluate the efficacy of drug therapy.
IV. ACC/AHA chronic heart failure staging
The ACC/AHA recommends that chronic heart failure be divided into four stages. Phase I, heart failure susceptibility phase: the presence of risk factors for the development of heart failure, the absence of obvious abnormalities in cardiac structure and function, and the absence of signs and symptoms of heart failure. Risk factors include: hypertension, coronary atherosclerosis, diabetes mellitus, alcoholism and use of drugs toxic to the heart, history of rheumatic fever, and family history of cardiomyopathy. Phase II, asymptomatic heart failure stage: organic heart disease without signs and symptoms of heart failure. For example, left ventricular hypertrophy and fibrosis, left ventricular enlargement and reduced contractility, asymptomatic valvular heart disease, old myocardial infarction, etc. Stage III, heart failure phase: organic heart disease with recent or previous signs and symptoms of heart failure. Stage IV, intractable or end-stage heart failure: severe organic heart disease with signs and symptoms of heart failure at rest even with reasonable medication.