Dr. Vinson is an emergency physician at Kaiser Permanente Sacramento Medical Center, a chair of the CREST (Clinical Research on Emergency Services and Treatment) Network, and an adjunct investigator at the Kaiser Permanente Division of Research. He also hosts Lit Bits, a blog that follows the medical literature at http://drvinsonlitbits.blogspot.com. Dr. Ballard is an emergency physician at San Rafael Kaiser, a chair of the KP CREST (Clinical Research on Emergency Services and Treatments) Network, and the medical director for Marin County Emergency Medical Services. He is also the creator of the Medically Clear podcast on iTunes or at https://medium.com/medically-clear. Follow him on Twitter @dballard30. Read his past articles at http://bit.ly/EMN-MedClear.
We all know that the Valsalva maneuver is one of the most effective and least risky first-line approaches to paroxysmal supraventricular tachycardia, even recommended by the American Heart Association and the like. (Circulation 2003;108:1871; Lancet 1988;1:1181.) But that doesn't mean clinicians always employ it or even know how to use it properly.
The customary Valsalva puts the patient in a supine or semi-recumbent position and has him exhale forcefully for 15 seconds against a closed glottis after a normal inspiratory effort. The strained exhalation can be accomplished by having the patient blow into a 10 mL syringe to the point of just moving the plunger, and the maneuver can be repeated if unsuccessful. But success rates range from six to 54 percent (Eur J Emerg Med 2012;19:346), and those low rates demonstrate how lack of education and technique standardization can greatly handicap outcomes. The truth is that physicians often don't know how to correctly apply the maneuver, so it's not routinely used as a first-line therapy. (Emerg Med Australas 2004;16:284.)
A new study from Britain, however, published in Lancet by Appelboam, et al., adds a new twist to the Valsalva. (2015;386:1747.) The researchers modified the technique by adding a leg lift at the end to attenuate the natural sympathetic surge that follows the Valsalva strain. The Modified Valsalva Maneuver begins with the patient in a semi-recumbent position performing strained exhalation for 15 seconds. Upon completing the strain, the patient's torso is dropped into a supine position while undergoing a passive leg raise at 45 degrees for 15 seconds. The patient is then restored to the initial position for 30 seconds. If paroxysmal supraventricular tachycardia (PSVT) persists, these steps can be repeated once.
This modified Valsalva maneuver restored sinus rhythm in 43 percent of the 214 patients with narrow complex PSVT in Appelboam's study, compared with 17 percent in the standard Valsalva group. (Adjusted odds ratio for success was 3.7 [95% CI 2.3-5.8; p<0.0001]). Patients who failed to respond to both versions of the Valsalva maneuver were treated with intravenous adenosine: 69 percent in the standard group vs. 50 percent in the modified.
This is promising new evidence. The methodology of the maneuver makes physiologic sense and seems easy to deploy in practice. How about a real-life trial? This is what happened when one of us (Dr. Ballard) gave it a go.
Putting into Practice
A 60-year-old patient presented with palpitations and tachycardia. A quick perusal of the patient's medical record demonstrated a known history of PSVT. The patient was nontoxic but glistened with sweat and exuded anxiety. His heart rate was 220 bpm on the ECG, regular, and looked a lot like narrow-complex PSVT.
We tried the modified Valsalva maneuver. The patient made the stopper of the syringe flicker a bit for 15 seconds, and then down went his head and up went his legs. The monitor, however, did not blip; it kept on ticking along double time. “I'll put in an IV and ask Charles to get the adenosine,” the nurse said and abruptly left the room.
Sure enough, after returning to a semi-recumbent position, there was no change in rhythm. The patient was offered another round of the modified Valsalva, but we ultimately opted for the adenosine instead. A few minutes later, he was back in normal sinus rhythm. No one involved seemed impressed by the Appelboaming.
Based on an n of one, this particular piece of new research may not be ripe for robust knowledge translation, but the maneuver is quite simple and easy to remember — 15 seconds of blowing, 15 seconds of leg raising — and we will consider trying it again.
This technique (done twice if needed) worked two of five times in Appelboam's hands. If we achieve a rate in keeping with that trial (40%), we'll save a number of patients an IV insertion and the uncomfortable experience of adenosine.
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