The modified Valsalva maneuver is an easy, non-invasive technique to help stop a fast heartbeat called paroxysmal supraventricular tachycardia (PSVT) in patients who are stable. It works by stimulating the vagus nerve, which helps slow down the heart rate. This method has a success rate of about 43%, which is more than double the effectiveness of the standard Valsalva maneuver, which only works about 17% of the time.
The steps and physiology
Venous return. Step 1, the strain phase. Position the patient in a semi-recumbent position. Give the patient a 10 ml syringe and ask them to blow hard enough trying to move the plunger. Maintaining a 15 seconds strain increasing an internal target pressure of about 40 mmHg. Step 2, immediately lay patient flat at the exact 15 seconds mark, raise and support leg at 45 degree angle for another 15 seconds. This increases venous return and further increase vagal tone.
Atrial stretch. With the increasing venous return from step 1 and 2, this stretches the atrium.
Cardiac mechanoreceptor activation. This stretch signals the brainstem (medulla) via the vagus nerve (cranial nerve X), enhancing parasympathetic (vagal) activity to slow down the heart rate and balance cardiac output. Step 3. Return the patient to a semi-recumbent position and monitor their heart rhythm (ECG) for about 45 to 60 seconds. The process can be repeated up to a maximum of 3 times if unsuccessful.
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