**8. Use of acute medication tests for the diagnosis of HF**

It is known that the manifestation of congestion is best reversed against the background of the use of diuretics, while congestion in the lungs is quickly stopped by nitroglycerin. However, nitroglycerin is poorly tolerated by some patients, and it can also be effective for spasms of any origin, including bronchial asthma. Thus, the specificity of reducing shortness of breath after using nitroglycerin is not great. The use of diuretics seems to be a more effective way to detect the relationship of low exercise tolerance with fluid retention in the patient's body.

A sample with torasemide was developed for use in outpatient clinics for the differential diagnosis of dyspnea of cardiac and non-cardiac origin with a sensitivity of 89% and specificity of 82%.

Method of performing the test [22]. In the morning, all patients undergo a 6-minute walking test. Then the patient should take torasemide 5 mg. 6-minute walking test is repeated every other day, all other things being equal. The increase in walking distance should be at least 15 m.

The test with torasemide is not expensive and can be performed by any medical professional without special training. The test can be used as the first stage of differential diagnosis in an outpatient environment in a patient with cardiovascular disease and dyspnea of unknown origin.

### **9. Complex systems for assessing the probability of having HF**

The newly created H2FPEF score allows you to accurately and quickly assess the probability of having HF in a patient [23]. Obesity (body mass index >30 kg/m2 ), atrial fibrillation, age > 60 years, treatment with ≥2 antihypertensive drugs, E/e' > 9, and pulmonary artery systolic pressure > 35 mm Hg were associated with HF. Atrial fibrillation gives 3 points, obesity - 2 points, other signs-1 point each. If the scale value is 0–1, it is very likely to exclude SN, if it is 6 or more points, it confirms it. Values from 2 to 5 require the use of clarifying methods (**Figure 1**).

The 'HFA-PEFF diagnostic algorithm' is also proposed [24]. In accordance with this algorithm, a pre-test assessment of the probability of CH is first performed. For this purpose, the presence of such risk factors for HF as obesity, hypertension, diabetes mellitus, the elderly, and atrial fibrillation is evaluated. Routine laboratory tests (sodium, potassium, urea, and creatinine, liver function tests, HbA1c, thyroid stimulating hormone, full blood count, ferritin, transferrin saturation, and hemoglobin), electrocardiogram and echocardiography are performed. In the absence of an obvious extracardial cause of symptoms and the presence of risk factors for heart failure, even at normal levels of natriuretic peptides, HF should be suspected.

The next step is an in-depth echocardiographic study, including E/e', left atrial volume index, LV mass index, relative LV wall thickness, tricuspid regurgitation rate, global longitudinal LV systolic strain, and serum natriuretic peptide levels if not already done (**Table 1**). If the sum of points of the HFA–PEFF Score is 1 and less than points, the diagnosis of CH is considered unlikely, if 5 the diagnosis of CH is proven. Sum 2–4 requires a transition to the next stage of diagnostics.

At Step 3 is recommended an echocardiographic or invasive hemodynamic exercise stress tests. The HF criteria for performing stress echocardiography are the average E/e 'ratio at peak stress increases to ≥15, with or without a peak tricuspid regurgitation velocity of >3.4 m/s. If the above-mentioned signs are not detected during the exercise echocardiography, then an invasive test should have performed. An elevated LV filling pressures at rest (LVEDP ≥16mmHg) or/and a high mean pulmonary capillary wedge pressure (mPCWP≥15mmHg) at rest is confirmed HF.


#### **Figure 1.**

*The H2FPEF score with associated probability of having heart failure [23].*



*Features of Diagnostics and Differential Diagnostics of Chronic Heart Failure in Outpatient… DOI: http://dx.doi.org/10.5772/intechopen.95863*

#### **Table 1.**

*The HFA–PEFF score (step 2).*

In the absence of detection of these indicators, a stress test is required. An increase in peak exercise PCWP ≥25 mmHg is interpreted as proof of the diagnosis of HF.

Step 4 involves clarifying the cause of HF. Sometimes it is necessary to perform cardiac magnetic resonance imaging, computed tomography, positron emission tomography, myocardial biopsy, genetic and special laboratory tests.

Performing the algorithm further in step 2 is not appropriate for routine practice due to the need for high-level specialists and the need for invasive diagnostics, which increases the risk for the patient. Moreover, difficulties may arise even when evaluating E/e' [25].
