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Adenosine for the Treatment of PSVT
in the Prehospital Arena: Efficacy
of an Initial 6 mg Dosing Regimen
Lynn K. Wittwer, MD, FACEP;1 Marc D. Muhr, BA, EMT-P2
1. Medical Program Director, Clark County
EMS, Vancouver WA; Director,
Department of Emergency Medicine,
Southwest Washington Medical Center,
Vancouver, Washington USA
2. Assistant to the Medical Program Director,
Clark County EMS, Vancouver,
Washington USA
Correspondence: Lynn K. Wittwer, M D
Medical Program Director
Clark County EMS
PO Box 1600
Vancouver, WA 98668 USA
Key Words: adenosine; cardioconversion; paramedic; prehospital;
PSVT; standing orders; supraventiclar
tachycardia; tachycardia
ALS = advanced life support
A-V = atrio-venticular
BLS = basic life support
E C G = electrocardiographic rhythm
EMS = emergency medical services
IV = intravenous
mg = milligram
MIR = medical incident report
M P D = medical program director
PSVT = paroxysmal supraventricular
SVT = supraventricular tachycardia
Received: 28 May 1996
Accepted: 30 September 1996
Revisions received: 08 November 1996
Objective: To confirm the efficacy of prehospital administration of adenosine, using
a 6 milligram (mg) initial dosing regimen,
for the treatment of paroxysmal supraventricular tachycardia (PSVT).
Methods: Urban, suburban, rural emergency medical services (EMS) system in
Clark County, Washington with advanced
life support (ALS) patient transports. Concurrent, paramedic Medical Incident Report
(MIR) review was conducted for 102
patients receiving prehospital adenosine
during a 42-month period. Patients were
administered 6 mg of adenosine using an
intravenous (IV) bolusfollowed by 10 ml of
balanced salt solution flush. If the patient's
rhythm remained unchanged, the dosing regimen was increased to 12 mgfollowed by a
10 mlflush. This was repeated once more if
the rhythm remained unchanged, to a total
maximum dose of 30 mg. Medical direction
for administration of adenosine was in the
form of standing orders rather than direct
(on-line) medical control.
Results: Seventy-four of 102 patients had
PSVT as determined by physician analysis
of the initial six-second electrocardiographic rhythm strip (ECG) recording. Sixty-six
of these patients converted their cardiac
rhythm from PSVT using adenosine; 46
(70%) converted with the initial 6 mg
bolus. Fifteen patients converted after
receiving the second dose (12 mg); and five
patients required 30 mg.
Conclusion: These results show that for
paramedics, adenosine is an effective treatment for PSVT. An initial bolus of 6 mg
converts the majority of cases. Eighty-nine
percent of cases of confirmed PSVT converted with adenosine administration.
Wittwer LK, Muhr MD: Adenosine for
the treatment of PSVT in the prehospital
arena: Efficacy of an initial 6 mg dosing
regimen. Prehospital and Disaster Medicine
Adenosine is a short-acting, purine nucleoside that is effective in blocking atrioventricular (AV) node conduction. The
intravenous administration of adenosine
has been used successfully for the treatment and diagnosis of various cardiac
dysrhythmias in both adults and children. 1 ' 2 Due to its rapid onset of action,
short half-life (<15 seconds), level oi
efficacy, and low rate of complications^
adenosine appears to be an attractive
choice in the acute management of paroxysmal supraventricular tachycardia
(PSVT) in the out-of-hospital setting.
Recent reports have supported the
use of an initial 12 mg bolus of adenosine as the method of choice for prehospital treatment of PSVT with as high as
80% successful conversion.4-5 Data provided with the product by the manufacturer indicates a 60% conversion succes;
rate when using 6 mg as the initial bolu;
dose. The purpose of this study was tc
confirm that in the prehospital setting
the administration of 6 mg of adenosinc
successfully converts the majority o
PSVT and should continue to be con
sidered as the starting point for pharmacologic intervention for PSVT.
Clark County, Washington USA, sup
ports a population of approximate!;
280,000 persons, residing in urban, sub
urban, rural, and wilderness areas. Threi
Advanced Life Support (ALS) transpor
agencies provide emergency medica
services (EMS) for this population
Paramedics in Clark County, Washing
ton are trained in the use of adenosin<
for the treatment of supraventricula
tachycardia (SVT), specifically paroxys
mal supraventricular tachycardia, parox
ysmal atrial tachycardia, and othe
supra-venticular tachydysrhythmias
Treatment of PSVT by paramedics ii
Prehospital and Disaster Medicine
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Vol.12, No.
Wittwer et al
this setting is governed by standing orders rather than
direct (on-line) medical control.
Training for management of paroxysmal supraventricular tachycardia includes focus on primary tachycardia recognition, differentiation between stable and
unstable patients, and provision of the proper treatment
sequence as outlined by the American Heart Association (AHA).6 Treatment of paroxysmal supraventricular tachycardia includes an initial attempt at vagal
maneuvers in the form of carotid sinus massage (CSM)
or Valsalva maneuver (CSM is not attempted in those
patients with known coronary artery disease). Persistence of PSVT then is managed pharmacologically as
follows: 1) establishment of a large bore intravenous
(IV) line (antecubital is the preferred site) with two port
tubing; 2) administration of a rapid 6 mg bolus of
adenosine intravenously (IV), followed rapidly with a
bolus of 10 ml balanced salt solution. Continuous electrocardiographic (ECG) monitoring is required during
administration to record results and any conversion dysrhythmias; 3) an additional 12 mg bolus (x2 prn) of
adenosine is administered as per the previously
described procedure for persistent or recurrent paroxysmal supraventricular tachycardia. Patients not responding to the maximum of 30 mg are transported and priority symptoms (e.g., chest pain, shortness of breath)
are treated as per standard protocol.
or 30 mg of adenosine. Of the 66 patients who converted, 46 (70%) received only a 6 mg bolus with resolution
of their PSVT. Fifteen (23%) patients converted after
18 mg, and five (7%) patients converted after the administration of a total of 30 mg adenosine.
Of those persons who successfully converted from
PSVT, 70% were female (46) and 30% were male. The
average age was 57 �.8 years for all patients whose
rhythm converted with a 6 mg bolus, 45 �.6 years for
patients who converted with 18 mg, and 48 �.5 years
for patients who converted with 30 mg.
Patient signs and symptoms prior to adenosine administration were grouped as: 1) 44 of the 74 patients
(59.4%) correctly diagnosed with PSVT initially complained of increased heart rate or palpitations; and 2) 33
(44.6%) complained of chest pain and/or pressure; 3) 27
(36.5%) described shortness of breath; and 4) 24
(32.4%) had neurologic symptoms such as weakness,
dizziness, vertigo, or a transient decrease in mentation
during their episode. Forty-eight patients (64.9%) had
two or more of the above symptoms and signs prior to
pharmacologic intervention. There was no relationship
between conversion success and presence of specific
symptoms and signs, nor was there a relationship evident between symptoms and the dose required for conversion of the tachycardia.
Medical Incident Reports (MIRs) were completed by
the transporting paramedic and were forwarded to the
Medical Program Director (MPD) and his staff for
input into a data base. Electrocardiographic analysis was
made using the standard three leads. Analysis of the
ECG strip was confirmed by the Medical Program
Director as well as by two physicians and one paramedic.
Differing interpretations were re-evaluated by the
Medical Program Director for a final interpretation of
the ECG rhythm. The MIRs were reviewed by the same
panel to determine indications for adenosine, associated
symptoms and signs, proper administration technique,
relevant medical history, conversion, and dose.
Associated signs and symptoms were ascertained during review of the patients MIR and categorized as: 1)
chest pain/pressure; 2) increased heart rate/"palpitations;"
3) shortness of breath; and 4) neurological impairment.
Gausche et al recently reported the efficacy of adenosine
for the pharmacologic treatment of PSVT. An initial
12 mg dosing regimen resulted in successful conversion
of 80% (67 of 84 patients).4 Other studies have supported successful conversion rates of greater than 80%7>8
using a dosing regimen of 6 mg, followed by 12 mg,
followed by 12 mg. Furlong et al, using the initial 6 mg
dose, indicated positive results in 57% of the total
patients converted from PSVT. The results in the current study indicate that 66 of 74 (89%) cases of confirmed PSVT were converted using adenosine with the
majority (46 of 66 or 70%) converted following the initial 6 mg dose.
Accurate rhythm interpretation remains paramount
for the administration of adenosine, as it would not be
expected to convert certain rhythms that can mimic
PSVT (e.g., atrial fibrillation, atrial flutter).9 In the 28
cases (27%) of incorrect initial rhythm identification, no
One-hundred two patients were included in the data pool untoward side effects (identified as exacerbation of the
as having been administered adenosine in the prehospital patient's current signs and/or symptoms, new onset of
setting during the 42-month study period. Seventy-four chest pain or pressure, shortness of breath, and/or
of the 102 (72%) initial rhythm strips were confirmed as changes in mentation) were experienced by patients in
paroxysmal supraventricular tachycardia by physician the prehospital setting as a result of adenosine adminisreview. The remaining rhythms were identified as: 1) 19 tration. It remains unknown whether any in-hospital
(19%) were atrialfibrillation;2) three each (6%) were atri- difficulties were encountered as a result of administraal flutter or wide-complex tachycardia of uncertain type; tion of adenosine in the prehospital setting.
3) two (2%) were sinus tachycardia; and 4) one (1%), venIn addition, in 27 of the 28 initially incorrect intertricular tachycardia. Of special note, one case of wide- pretations, the paramedics were able to identify the
complex tachycardia of uncertain type converted to sinus underlying rhythm and provide appropriate treatment
rhythm following the administration of adenosine.
after the administration of the adenosine. One patient
Of the 74 tracings verified as PSVT, 66 (89%) cases with wide complex tachycardia of uncertain type conconverted from PSVT using total doses of either 6, 18, verted to sinus rhythm after the initial 6 mg bolus.
July-September 1997
Prehospital and Disaster Medicine
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Adenosine Treatment of PSVT
Administration of adenosine is effective for the treatment of patients with PSVT in the prehospital arena.
Paramedics can use adenosine appropriately under
standing orders for the prehospital treatment of supraventricular tachydysrhythmias. Success depends on initial rhythm interpretation, use of the proper technique
for administration, and initial dosing regimen. A 6 mg
dose of adenosine, during prehospital administration,
converts the majority of patients with PSVT, and
should be considered as the starting point for pharmacologic intervention.
The authors thank all the paramedics in Clark County
for their participation in data collection; and Marty Bell,
MD, Truman Cleaver, MD, Robert Swenson, MD, and
Mary Beth Jones, MD for their assistance with manuscript review and preparation.
1. Griffith M, Linker N, Ward D, et al: Adenosine in the diagnosis of broad
complex tachycardia. Lancet 1988;1(8587) 672-675.
2. Clarke B, Rowland E, Barnes P, et al: Rapid and safe termination of
supraventricular tachycardia in children by adenosine. Lancet 1987;
3. Sharma A, Klein G, Yee R: Intravenous adenosine triphosphate during
wide QRS complex tachycardia: Safety, therapeutic efficacy, and diagnostic utility. AmJMed 1990;88:337-343.
4. Gausche M, Persse D, Sugarman T, et al: Adenosine for the prehospital
treatment of paroxysmal supraventricular tachycardia. Ann Emerg Med
5. Cairns CB, Niemann JT: Intravenous adenosine in the emergency department management of paroxysmal supraventricular tachycardia. Ann
Prehospital and Disaster Medicine
Emerg Med 1991,20:717-721.
6. American Heart Association: Textbook ofAdvanced Cardiac Life Support.
American Heart Association: Dallas, Texas. 1994,p40.
7. Furlong R, Gerhardt R, Farber P, et al: Intravenous adenosine as first-line
prehospital management of narrow-complex tachycardias by EMS personnel without direct physician control. Am J Emerg Med 1995;
8. McCabe J, Adhar G, Menegazzi J, et al: Intravenous adenosine in the
prehospital treatment of paroxysmal supraventricular tachycardia. Ann
Emerg Med 1992;21:358-361.
9. DiMarco J, Sellers T, Lerman B, et al: Diagnostic and therapeutic use of
adenosine in patients with supraventricular tachyarhythmias. JACC
Vol.12, No.3
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