Diagnostics
Heart failure can usually be diagnosed by a detailed medical consultation (the so-called medical history) and a physical examination. In the laboratory there are special markers (including BNP and NT-proBNP) which the doctor can determine and which confirm the suspicion of heart failure. A cardiac echo (= ultrasound of the heart) can confirm the diagnosis of cardiac insufficiency.
Ultrasound would reveal massively enlarged ventricles and atria, a restriction of ventricular movement and possible defects in the heart valves, which may be the cause of the heart failure. Another way to detect cardiac insufficiency is the ECG. The ECG, or electrocardiogram, provides information about the activity of the heart muscle by recording electrical potential fluctuations of the heart muscle cells.
Various recordings are used for this purpose (I, II, III according to Einthoven, aVF, aVL and aVR according to Goldberger, as well as the chest wall recordings V1-V6). The deflections in the ECG correspond to the propagation of excitation in the individual heart structures. Thus, the P-wave (the first deflection) symbolizes the propagation of the excitation in the atria, the P-Q-segment the propagation of the excitation from the atrium to the ventricle, the QRS-complex the propagation of the excitation in the ventricles and the T-wave that follows symbolizes the discharge (repolarization) of the ventricles.
In this way, the ECG can be used to make statements about the position type of the heart, its rhythm and its frequency. If changes occur, one can then draw conclusions about various diseases. For example, a position type that was previously “normal”, i.e. an indifference type, and is now a right type or overexcited right type in the ECG, can be a sign of right heart failure.
A newly appeared left type or overexcited left type is always a sign of acute left heart stress (for example, weakness of the left heart) or a heart attack. With the help of the QRS complex, which represents the ventricles, statements can also be made about possible heart failure. In this case, the amplitudes of the R- and S-wave in the ECG would increase.
This correlation is shown in an equation with the help of the so-called Sokolov-Lyon index. For a left heart weakness or left heart enlargement, the index would be greater than or equal to 3.5mV.In healthy people the value would be less than 3.5, and for right heart enlargement and right heart failure the index would be greater than or equal to 1.05mV. Another indication for a cardiac insufficiency in the ECG would be a change in the T-wave, i.e. the reduction of excitation. This can then manifest itself in a negative (downward pointing) T-wave. If the atrium is enlarged as a sign of cardiac insufficiency, this would result in a bipolar P-wave.