COMPARISON OF PREHOSPITAL MONOMORPHIC AND POLYMORPHIC VENTRICULAR-TACHYCARDIA - PREVALENCE, RESPONSE TO THERAPY, AND OUTCOME

Objective: Monomorphic ventricular tachycardia (MVT) is the most commo n form of prehospital ventricular tachycardia (VT). Recent literature suggests that polymorphic ventricular tachycardia (PVT) is more common during cardiopulmonary arrest than previously thought but responds po orly to advanced cardiac life support (ACLS) therapy. We undertook thi s study to determine the prevalence, response to therapy, and outcome of both MVT and PVT in the prehospital sudden cardiac death victim. De sign: Retrospective prehospital chart review from 1987 to 1991. Settin g: Municipal, fire department-based, multitiered emergency medical sys tem serving a population of approximately one million. Participants: A dult patients older than 18 years experiencing prehospital, nontraumat ic cardiopulmonary arrest with VT occurring at any time during the res uscitation. VT was defined as PVT if the QRS-complex configuration was not stable when viewed in a single electrocardiographic lead (ie, epi sodic changing of the QRS-complex electrical axis, amplitude, or both or the presence of more than two QRS-complex morphologies). Outcome wa s defined in terms of both the presence or absence of spontaneous circ ulation at the end of the prehospital phase of care and ultimate outco me (survival to hospital discharge or death). Four hundred seventy-six patients met entry criteria; 37 patients were excluded because of inc omplete medical records, and 439 patients were used for data analysis. Interventions: ACLS therapy based on the 1987 American Heart Associat ion guidelines. Results: MVT occurred in 323 patients (73.6%), with 11 9 (36.8%) showing return of spontaneous circulation (ROSC) in the preh ospital setting; 35 MVT patients (10.8%) survived to hospital discharg e. PVT occurred in 116 patients (26.4%), with 48 (41.4%) showing ROSC in the prehospital setting; 15 PVT patients (12.9%) survived to hospit al discharge. The use of ACLS therapy (defibrillation, endotracheal in tubation, medication usage) between the two rhythm groups was not stat istically different. The P values for ROSC, ultimate outcome, and use of ACLS therapy were all not significant. Conclusion: We conclude that PVT is a common rhythm occurring in prehospital cardiopulmonary arres t that responds as well as MVT to ACLS therapy. Until prospective data are available, standard ACLS therapy should be used in all forms of p rehospital VT occurring during cardiopulmonary arrest.