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This rare dysrhythmia classically presents with paroxysms of syncope and polymorphic “twisting” of the QRS complexes (Figure 10.1). Torsades de pointes (TdP) in adults is usually “pause dependent,” flourishing when the intrinsic heart rate drops below 80 to 100/minute. A variety of antidysrhythmics (essentially all, aside from lidocaine and calcium channel or beta‐adrenergic blocking agents), antihistamines, antimicrobials, and psychoactive drugs, along with metabolic disorders, can precipitate TdP in adults. Field treatment consists of countershock when unstable and transcutaneous pacing or isoproterenol (titrated to a heart rate >120/minute). Magnesium sulfate, 2 g as a rapid IV bolus, is also suggested for those who fail countershock. In children, TdP is rare, inherited, and treated with slowing heart rate.

A more practical problem is mistaking VT or VF for TdP. VT and VF often display some changes in QRS complex appearance. EMS clinicians may mistake these variations for the classic, but rare, QRS twisting. If recurrent polymorphic VT occurs in a patient with one or more of the aforementioned risks, treatment should be started. Otherwise, orders and protocols should focus on the treatment of common VT.