Accuracy of Arrhythmia Recognition in Paramedic Treatment of Paroxysmal Supraventricular Tachycardia: A Ten-year Review

Objectives. To examine trends in paramedic rhythm misidentification rates in the use of adenosine for presumed paroxysmal supraventricular tachycardia (PSVT) over a ten-year period, and to determine variables associated with rhythm misidentification. Methods. The authors conducted a retrospective analysis of all cases in which paramedics treated presumed PSVT with adenosine from 1993 to 2002. Rhythm strips were categorized as narrow or wide-complex and regular or irregular. Appropriate use of adenosine was defined as narrow-complex regular tachycardia with no visible P waves and rate greater than 140 beats/min. Results. The authors studied 224 patients with a mean age of 60 years (range, 15-94 years); 157 (70%) were female and predominantly white. The majority (54%) of patients had initial heart rates of 161-200 beats/min. Forty-nine percent of the patients had a previous history of PSVT. Inappropriate use of adenosine occurred in 45 (20%) cases. Misidentification rates per year ranged from 9% to 31% with the lowest rate occurring after a targeted education program on tachydysrhythmias. An initial heart rate of < 160 beats/min (χ² = 14.81, p < 0.001) and absence of a medical history of either fast heart rate or palpitations (χ² = 11.35, p = 0.001) were associated with inappropriate use of adenosine. Conclusion. Paramedics in this emergency medical services system are more likely to use adenosine appropriately for patients with initial heart rates of >160 beats/min and a history of rapid heart rate or palpitations. Further studies are required to identify factors associated with rhythm interpretation errors in the prehospital setting as well as to evaluate error reduction strategies.