1. Tachycardia with narrowed QRS complex
– In order to decrease conduction velocity and to increase the refractory period at the atrioventricular node level;
– Decreased atrial refractory period;
– Decrease in frequency electrical impulse formation in the sino-atrial node.
2. Exposure of the block location in case of atrioventricular block 2: 1
– Increasing the block shows a suprahisian location;
– Improving the atrio-ventricular conduction shows an infrahisian location.
3. Diagnosis of hypersensitivity of the carotid sinus
– In case of syncope.
4. Supraventricular tachyarrhythmias
– Increasing the block at the atrioventricular node level and highlighting atrial activity (P wave of atrial tachycardia or F waves of atrial flutter);
– It can convert certain supraventricular tachycardias: intra-nodal reentrant tachycardia, rarely accessible and extremely rare that the beam can slow down or even convert atrial tachycardia.
Contraindications of vagal maneuvers
– Carotid sinus massage is contraindicated in patients with murmurs or stenosis of the carotid arteries or transient ischemic attack (within the past 3 months).
– Recent myocardial infarction, history of ventricular arrhythmias, immobilizer, blindness or cognitive impairment.
Complications of vagal maneuvers
– Sinus pauses;
– Atrioventricular block;
– Rarely, tachyarrhythmias;
– Retinal detachment (in case of oculo-cardiac reflex);
– Water intake, anxiety (if immersion reflex).
Vagal maneuvers as a diagnostic modality in tachyarrhythmias
1. Carotid sinus massage
Mode of action: glossopharyngeal nerve;
Method of making: patient in supine with head hyperextension can feel the carotid sinus (inferior on the mandible angle at the intersection with thyroid cartilage). It is applied pressure for 5-10 seconds with continuous ECG monitoring and TA;
Possible complications: dizziness, hypotension, syncope, ventricular tachycardia, ventricular fibrillation, asystole, neurological complications.
2. Valsalva maneuver
Method of making: patient in supine, after a normal inspiration he is asked to expire forced with the glottis closed for 10 seconds. Signs of proper maneuver- distenisa of the jugular vein, facial congestion and abdominal muscle hyper-tonicity;
Possible complications: eardrum rupture, ventricular arrhythmias, systolic breaks
3. Diving reflex (immersion)
Mode of action facial nerve and vagus
Method of making: Patient in front of a pot of water with temperature of 10-20 degrees Celsius, large and deep enough for the patient to not touch the vessel with face or neck. After a regular inspiration, the patient is sinking with his face in the water; the more immersed surface is, the effect is more pronounced. The expected effect – bradycardia mediated by parasympathetic and vasoconstriction sympathetic mediated;
Possible complications: Anxiety, premature ventricular, aspiration, drowning.
4. Oculo–cardiac reflex (by pressing the eyeballs)
Mode of action: oculo-motor nerve;
Method of making: it is applied pressure on the eyeballs, the orbit or extra-ocular muscles;
Possible complications: Retinal detachment, ocular trauma, malignant ventricular arrhythmias.
Other maneuvers that may lead to the activation of the parasympathetic system: apnea, digital rectal examination, coughing, deep breathing, reflex-induced vomiting, intra-cardiac catheter placement, installation of a nasogastric tube, sitting on veins, Trendelenburg position.