Valsalva maneuver in medicine (tachycardia and vagus nerve)

The Valsalva maneuver (MV), named after the doctor Antonio Maria Valsalva, is a forced middle ear compensation maneuver, mainly used in medicine, especially in the cardiology field, but also in the underwater field.

What does the Valsalva maneuver consist of?

The Valsalva maneuver consists of a relatively deep inhalation followed by a forced exhalation with closed glottis lasting about 10 seconds.

What is the glottis?

The ” glottis ” is the upper segment of the larynx at the vocal cords, located at the below the epiglottis and above the cricoid cartilage. The glottis is, in simple words, the opening of the larynx and corresponds to the natural space that can form in the middle of the vocal cords and their respective arytenoid cartilages; it is not a permanent and fixed space  since it is affected by the activities and movements of which the larynx is the protagonist:  during breathing  the glottis takes the form of a triangle, while  during phonation (voice emission)  the glottis becomes a line thin interposed between the vocal cords. The glottis has three functions: it allows a correct  phonation; isolates the respiratory system from the digestive system, allowing the passage of food into the esophagus and air into the trachea. For further information:  Glottis: anatomy, functions, inflamed, tumor, images

What is the Valsalva maneuver for?

Initially this maneuver was used to remove suppuration and foreign bodies from the ear. Subsequently, the attention shifted to the hemodynamic variations produced by its execution which proved useful in the diagnostic process of numerous pathological, cardiological and non-cardiological conditions. It is also useful in the control of tachycardia.

Valsalva maneuver in tachycardia

The Valsalva maneuver is taught by cardiologists to patients subject to paroxysmal tachycardia crisis to block it , as the vagus nerve (X cranial nerve) is stimulated, thus causing a parasympathetic vagal stimulation that slows the heart rate.

The dynamics of MV involves four phases:

  1. voltage start phase,
  2. voltage phase,
  3. relaxation phase,
  4. recovery phase.

Normally, phase I is characterized, during exhalation with closed glottis, by the increase in intrathoracic pressure and systolic blood pressure due to compression of the aorta. Subsequently, during phase II, there is a decrease in venous return and systolic blood pressure secondary to the persistence, at the intrathoracic level, of a positive pressure. At the same time, there is an increase in heart rate. During the subsequent relaxation and recovery phases, the rapid reduction of intrathoracic pressure causes the activation of a series of physiological compensation mechanisms. Specifically, the rapid modification of the blood volume present in the pulmonary vascular system causes a sharp reduction in systolic blood pressure (phase III) and, subsequently,
peripheral sympathetic hyperactivity and the reduction of heart rate, determine the increase in systolic blood pressure (phase IV).

Is the Valsalva maneuver still useful?

MV has been widely used in “classic” semeiotics for the evaluation of heart failure patients and for a more in-depth evaluation of heart murmurs. The advent of more modern imaging methods such as echocardiography
has reduced the use of this maneuver in clinical practice. However, it still represents a valid aid in the echocardiography laboratory in the evaluation of the diastolic function of the left ventricle, in the evaluation of the extent of the obstruction to the outflow of the left ventricle in hypertrophic cardiomyopathy, and in the diagnosis of patency of the oval foramen (PFO). for the evaluation of the right-left shunt to it
associated. In addition, MV maintains a discreet utility in the classic semeiotic evaluation of numerous cardiovascular clinical conditions such as the diagnosis of systolic heart murmurs, autonomic dysfunction, arrhythmias and heart failure.

THE VALSALVA MANEUVER IN THE CLINICAL DIAGNOSIS

Valsalva maneuver and heart murmurs

The hemodynamic changes induced by the MV help with auscultation in the diagnosis between the different types of heart murmurs. When the systolic range and systemic blood pressure are reduced, the systolic murmurs of aortic and pulmonary stenosis and mitral and tricuspid insufficiency are reduced and the diastolic murmurs of aortic and pulmonary insufficiency and tricuspid and mitral stenosis reduce their intensity. Furthermore, the increase in the intensity of the murmurs during the execution of the MV in patients with obstructive hypertrophic cardiomyopathy distinguishes this type of murmur from other types of systolic murmurs, while the telesystolic murmur and the click of the mitral valve prolapse are
anticipated.

Valsalva maneuver and autonomic dysfunction

MV is used in the study of autonomic dysfunction by providing information on both the function of the sympathetic system and the parasympathetic system4, evaluating the pressure response to MV for the study of adrenergic function and using an index, the Valsalva ratio, for the study of the function. vagal. The Valsalva ratio is an index that allows an early detection of vagal dysfunction even in patients who still have to develop evident heart disease. It is given by the relationship between heart rate during phase IV of MV and heart rate during phase II. As a rule, there is an increase in heart rate during phase II as
response to the fall in blood pressure, while as a baroreflex response during phase IV an increase in blood pressure associated with a transient bradycardia is appreciated. In patients with autonomic dysfunction there is a loss of the increase in blood pressure and reflex bradycardia induced by MV.

Valsalva maneuver and arrhythmias

MV leads to an increase in vagal tone and slows the conduction and refractoriness of the atrioventricular node. In this way, this maneuver allows to: a) transiently reduce the heart rate in cases of sinus tachycardia by acting on the discharge rate of the sinus-atrial node; b) stop episodes of tachycardia from re-entry at the level of the atrioventricular node and atrioventricular re-entry; c) slatentizing (without interrupting) cases of paroxysmal supraventricular tachycardia, flutter and atrial fibrillation. In contrast, MV has no effect on ventricular tachycardia.

Valsalva maneuver and heart failure

In the evaluation of the patient with heart failure, the execution of the MV in bed of the patient is of great help allowing to document the possible presence of ventricular dysfunction. In fact, the blood pressure response correlates well with functional capacity, plasma levels of neurormones and cardiac hemodynamics, also providing useful prognostic information. In addition, the MV can also be used in the patient’s bed in association with vascular ultrasound by evaluating the changes in the area of ​​the transverse section of the internal jugular vein in order to obtain an indirect measurement of the central venous pressure. In this way it is possible to significantly limit the use of invasive procedures for measuring the right atrial pressure and monitor the management of the patient with heart failure.

 

Leave a Comment