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Palpitations in a six-year-old boy
The Journal of Emergency
Medicfne,
Vol. 8, pp. 335-339,
Printed in the USA
1990
. CopyrIght
0 1990 Pergamon Press plc
PALPITATIONS IN A SIX-YEAR-OLD BOY Sara K. Scott, Reprint address:
MD
Emergency Medical Services, Denver General Hospital, Denver, Colorado Sally Scott, MD, Emergency Medical Services, Denver General Hospital, 777 Bannock St., Denver, CO 80204-4507
0 Dr. Rodney LoeMrer: Today’s sented by Dr. Cheryl Melick.
case will be pre-
caffeine ingestion or hot chocolate?
was a 6-year-old boy brought to the emergency department by his mother with a chief complaint of rapid heartbeat starting a few hours earlier while at play. In the past, he had had multiple similar episodes which were relieved by relaxing and watching television. This time, the treatment was unsuccessful and he was brought to the hospital. The boy denied recent illness, chest pain, dyspnea, or prior evaluation for his complaint. His mother related a personal history of paroxysymal atria1 tachycardia that had never been evaluated, and was told when her son was born that he had the same problem. On physical examination, the boy was a well nourished, well developed male sitting comfortably in no acute distress. His skin was warm and dry. His blood pressure was 102 by palpation. He had a heart rate of 120 BPM, a respiratory rate of 18, and was afebrile. His head and neck examination was unremarkable. He demonstrated minimal jugular venous distention when sitting upright. His lungs were clear to auscultation. His heart rate was rapid and regular and he demonstrated no murmurs, rubs, or gallops. His abdomen was soft and nontender. His extremities were normal. Neurologically he was nonfocal with age-appropriate mentation. His rectal examination was unremarkable. about
0 Dr. Stephen Cantrill: Was there any history
B
Emergency
=ZYZZZ
Sarah K. Scott,
cola beverages,
coffee, tea,
0 Dr. Melick: No. We asked about hot chocolate. episodes usually were preceded by exertion.
?? Dr. Cheryl Melick: The patient
?? Dr. Loeffler: Are there any questions history and physical examination?
including
?? Dr. Ilya Chern:
Had he ever fainted
His
during these
episodes? 0 Dr. Melick: No, he would get tired and lie down to rest instead of playing. IJ Dr. John Marx: Was there any evidence of cardiomyopathy or failure. Did he have an enlarged liver? 0 Dr. Melick: No, his liver wasn’t enlarged. As I mentioned, he had clear lungs and was without evidence of peripheral edema.
?? Dr. Marx:
What did you do for him‘?
0 Dr. Melick: He was placed on a cardiac monitor and three liters of oxygen by nasal cannula. We obtained an ECG (Figure 1). 0 Dr. Loeffler: Dr. Melick do you mind interpreting this ECG for us? 0 Dr. Melick: The ECG shows a narrow complex tachycardia with a rate of just over 200 BPM. There were no obvious signs of Wolfe-Parkinson-White Syndrome (WPW).
the
0 Dr. Loeffler: What happened
of
next?
Case Records features case conferences presented at teaching institutions. This section is coordinated by MD.
0736-4679190 335
$3.00 + .OO
336
?? Dr. Melick: He remained stable and we opted to try vagal maneuvers to convert him. They were unsuccessful. At that point, we thought he needed to be moved to a major resuscitation room to be converted pharmacologically. The only problem with moving him was that we had three stabbings and six major motor vehicle accidents and two ventilators in the department. We didn’t have an appropriate room. 1 paged pediatrics and they graciously offered to come down to help monitor the child. 0 Dr. Ken K&g: Did you explore what medications were available in the home including thyroid medications, cocaine, or amphetamines? 0 Dr. Meiick: We didn’t take a toxicologic history partly because he had had palpitations multiple times and his mother had a similar history. 0 Dr. Kulig: Well she may just be saying that. Was a urine toxicology screen obtained? 0 Dr. Melick: No, I didn’t order one. 0 Dr. Marx: Supraventricular tachycardias in children typically occur with a normal heart. They are brought on by exercise, flus, or colds, or just nothing in particular. That appears to be the case with this child. Less commonly, certain anatomical predispositions exist including accessory electrical pathways, Ebstein’s anomaly, and mitral valve prolapse. 0 Dr. Melick: We did obtain a chest x-ray study which was normal. [7 Dr. Loeffler: The boy was admitted to an ICU bed where he was given verapamil, 0.07 mg/kg IV push, which rapidly converted him following unsuccessful vagal maneuvers. His ECG following conversion showed a sinus rhythm at 110 BPM (Figure 2).
?? Dr.
Marx: Was verapamil not used in the emergency department because you never had a place to administer it? 0 Dr. Melick: It was too chaotic in the emergency department, and an appropriate monitoring room and personnel were unavailable. It was preferred that the patient be taken to a quiet, monitored room with oneto-one nursing coverage. 0 Dr. Loeffler: While in the intensive care unit, after converting with verapamil, the patient received a loading
Sara K. Scott
dose of 350 pg of digoxin IV. He had no complications during his admission and was discharged on the second hospital day. 0 Dr. Cantrill: Did he get started on long-term digoxin?
?? Dr. LoeMer: He was discharged on 100 pg bid of digoxin. I have asked Dr. Michael Schaffer, a pediatric cardiologist at the University of Colorado Health Sciences Center to briefly discuss issues of cardiac irregularities in children. 0 Dr. Michael Schaffer: This case presents a number of issues involving the diagnosis and management of tachycardia. When a child comes into the emergency department, the first thing you need to do is assess the child’s overall status. In children, the mechanism of the tachycardia is not of primary importance. If the rhythm is not supporting an adequate blood pressure, you need to alter it immediately. I don’t think there is really a place for IV medical management of a patient who has vascular collapse. You DC cardiovert them to stop the dysrhythmia (1,2). The chance of hurting someone by shocking them is low, even if the underlying rhythm is sinus. But, if you give the wrong drug to the wrong tachycardia, you may hurt someone. This child came in with a narrow complex tachycardia, but what if he came in with a wide complex tachycardia. In adults you assume a wide complex tachycardia is ventricular in origin until proven otherwise. You frequently hear that a wide complex tachycardia is SVT with aberrant conduction. That is just wrong most of the time. Ninety percent of wide complex tachycardias in children are ventricular tachycardia (3). This child arrived with a narrow complex tachycardia and cardiovascularly was stable. Consequently, nothing needed to be done immediately. Next you obtained his history. Does the tachycardia start and stop abruptly? If it does, you are dealing with a reentry phenomenon. Reentry can be in the atrium, in the AV node, or through an accessory bypass tract. If the tachycardia is gradual in its onset, you are dealing with an ectopic focus and it can be anywhere, high in the atrium or down in the ventricles. So history is very helpful. Seven year olds can frequently give you an accurate history, while younger children are less clear. If a history can’t be obtained, an electrocardiogram must be obtained immediately. The presenter mentioned that the original electrocardiogram showed a narrow QRS complex without a delta wave. During orthodromic reciprocating tachycardia with Wolff-Parkinson-White syndrome, you won’t see the delta wave because the delta wave is caused by anterograde conduction over the
Palpitations
in a Six-Year-Old
337
Boy
NII
INTERPRETATION DOCTOR
DATE
i
Figure 1. ECG on admission to the emergency department. accessory pathway. During the tachycardia, the electrical wavefront goes down the AV node and retrograde up
the accessory pathway. So this patient’s ECG with a narrow QRS could be consistent with Wolff-ParkinsonWhite. You can’t tell with certainty until the patient converts to sinus rhythm (1). Given that fact, you don’t want to give this child digoxin until you know the underlying mechanism. Even verapamil is in many places thought to be inappropriate for acute management of tachycardia secondary to WPW. The implied risk with both is that they may enhance the rate of conduction over the accessory pathway. With a child who is stable and has a narrow QRS tachycardia, the next thing to look for are P waves. In this child’s ECG you can’t see them (Figure 1). If his P wave rate is different than his QRS rate he’s got AV dissociation, and this would mean that he doesn’t have a reentry phenomenon using an accessory pathway. It isn’t
possible to tell in this child, but if they were present it is very strong evidence that you are dealing with a ventricular ectopic focus. If you’ve seen a child and he looks well and you’ve recorded an ECG, but you can’t see P waves, vagal maneuvers should be attempted. In a seven year old, an ice bag in the face doesn’t work very well. In children, two years old and under, you can take an ice bag and put it in their face, right over the bridge of their nose (2,4). The diving reflex is induced and this slows the heart rate (1). In little babies this technique works very well. In a seven-year-old child it usually just tends to produce more anxiety, leading to screaming and production of catecholamines. In this setting tachycardia will not break. Other vagal maneuvers can be used in children. Every emergency department has a surgical glove. Having the child blow up the surgical glove is the equivalent of a Valsalva maneuver. Another technique is to take a 30
!
:
1
:
! ; :qf :
/ i i
/ [
! i
’/ -1..I
-. _ -1,. -” I-. i-
_,._1
I ;
t
Figure 2. Postconverslon ECG.
cc syringe and lock a stopcock on the end of it. Then try to get the child to blow it off. When you demonstrate, you don’t lock it on and it easily blows off. When you put it on for the child, lock it on then have him blow. This agai.n simulates a Valsalva maneuver. Some children convert themselves by standing on their heads. If you can find the vagal maneuver that works, these children won’t have to come into the emergency department every time they get palpitations. If the child is stable, you can teach the parents and reassure them that their child won’t die suddenly. If vagal maneuvers don’t work, other electrophysiological methods can be employed. If an esophageal electrode is available (4,5), it is easy to put it down the nose so the electrode is behind the left atrium. I have paced newborn babies until enough medication is on board to prevent the dysrhythmias. If pacing doesn’t work, then pharmacologic management is necessary. Verapamil is a nice agent, but an even
better agent is adenosine (6). Adenosine creates a temporary block. Its half-life is very short, and its effect is gone in half a minute. However, it is not approved for use in the U.S. at present. Verapamil blocks the AV node. If the tachycardia involves the AV node, it is effective (2). The problem with verapamil is it is often given for the wrong tachycardias (i.e., those not involving the AV node). In the operating room or post-operative intensive care unit, the patient with tachycardia is likely to have junctional tachycardia. If verapamil is given to such a patient, the preload is reduced by vasodilitation and the patient may become hypotensive. Hypotension also occurs with verapamil use in sinus tachycardia due to fever or hypovolemia. I think a valuable drug for treating unknown tachydysrhythmias is procainamide. It treats ventricular tachycardias, supraventricular tachycardias, and automatic foci. In a situation with a hemodynamically stable
Palpitations
in a Six-Year-Old
339
Boy
patient where the patient must be treated but the underlying mechanism is not known, use procainamide.
it probably should not be used (2,7). If for some reason you think you need to use it, you must have calcium and volume expanders available.
!J Dr. Loeffler: Any questions? 0 A physician: If procainamide is given, will it cause any problems when working up the patient electrophysiologically?
?? Dr. Schaffer: Yes, but the usual procedure is to let it wear off and then take the patient for electrophysiological studies. 0 Dr. Michael Radetsky: Should verapamil be given to infants and newborns?
I-J Dr. Schaffer: The party line is not to use it. Even when administered for the right reason, the newborn myocardium is extremely sensitive to verapamil. It is much more so than the older child or adult myocardium. You need to be very, very careful and unless you are inside an electrophysiology lab, or giving it to a child who has gotten it in the past and is known to tolerate it,
0 Dr. Kulig: If this child were unstable and you wanted to cardiovert him, what preconversion agents would you use?
0 Dr. Schaffer: In terms of sedation, I would probably use ketamine, 1 mg/kg IV. Ketamine also lasts longer for cardioversion and leaves the patient amnestic for the event. You can use just about anything with which you are comfortable. I frequently use Valium@ or Versed@, 0.1-0.2 mgkg IV. Short-acting barbiturates also work well in this type of patient. For cardioversion in an unstable patient I begin with 1 watt-se&g and if unsuccessful I increase the dose (in a stepwise fashion) up to a maximum of 4 watt-set/kg. For elective cardioversion of atria1 flutter, I may begin at a lower dose of l/2 watt-se&g (2). 0 Dr. Loeffler: Thank you, Dr. Schaffer, for your very practical comments.
REFERENCES Garson A Jr, Gillette C. Dysrhythmias. In: Heart disease in infants, children and adolescents. Baltimore: Williams and Wilkins; 1989: 925-39. Wilkinson JL. Management of paroxysmal tachycardia. Arch Dis Childhood. 1983;53:945-6. Garson A Jr. Ventricular dysrhythmias. In: Gillette DC, Garson A. Jr. Pediatric cardiac dysrhythmias. New York: Grune and Stratton; 1981;319. Dick M, Campbell R. Advances in the management of cardiac arrhythmias in children. Pediatr Clin North Am 1984;3 1: 1175-95.
5. Dick M II, Scott WA, Serwer GS, et al. Acute termination of supraventricular tachyarrhythmias in children by transesophageal atrial pacing. Am J Cardiol. 1988;61:925-7. 6. Overholt ED, Rbeuban KS, Gutgesell HP, Lerman BB, Dimarco JP, Usefulness of adenosine for arrhythmias in infants and children. Am J Cardiol. 1988;61:336-40. I. Kirk CR, Gibbs JL, Thomas R, Radley-Smith R, Qureshi SA. Cardiovascular collapse after verapamil in supraventricular tachycardia. Arch Dis Childhood. 1987:62:12656.
Medicfne,
Vol. 8, pp. 335-339,
Printed in the USA
1990
. CopyrIght
0 1990 Pergamon Press plc
PALPITATIONS IN A SIX-YEAR-OLD BOY Sara K. Scott, Reprint address:
MD
Emergency Medical Services, Denver General Hospital, Denver, Colorado Sally Scott, MD, Emergency Medical Services, Denver General Hospital, 777 Bannock St., Denver, CO 80204-4507
0 Dr. Rodney LoeMrer: Today’s sented by Dr. Cheryl Melick.
case will be pre-
caffeine ingestion or hot chocolate?
was a 6-year-old boy brought to the emergency department by his mother with a chief complaint of rapid heartbeat starting a few hours earlier while at play. In the past, he had had multiple similar episodes which were relieved by relaxing and watching television. This time, the treatment was unsuccessful and he was brought to the hospital. The boy denied recent illness, chest pain, dyspnea, or prior evaluation for his complaint. His mother related a personal history of paroxysymal atria1 tachycardia that had never been evaluated, and was told when her son was born that he had the same problem. On physical examination, the boy was a well nourished, well developed male sitting comfortably in no acute distress. His skin was warm and dry. His blood pressure was 102 by palpation. He had a heart rate of 120 BPM, a respiratory rate of 18, and was afebrile. His head and neck examination was unremarkable. He demonstrated minimal jugular venous distention when sitting upright. His lungs were clear to auscultation. His heart rate was rapid and regular and he demonstrated no murmurs, rubs, or gallops. His abdomen was soft and nontender. His extremities were normal. Neurologically he was nonfocal with age-appropriate mentation. His rectal examination was unremarkable. about
0 Dr. Stephen Cantrill: Was there any history
B
Emergency
=ZYZZZ
Sarah K. Scott,
cola beverages,
coffee, tea,
0 Dr. Melick: No. We asked about hot chocolate. episodes usually were preceded by exertion.
?? Dr. Cheryl Melick: The patient
?? Dr. Loeffler: Are there any questions history and physical examination?
including
?? Dr. Ilya Chern:
Had he ever fainted
His
during these
episodes? 0 Dr. Melick: No, he would get tired and lie down to rest instead of playing. IJ Dr. John Marx: Was there any evidence of cardiomyopathy or failure. Did he have an enlarged liver? 0 Dr. Melick: No, his liver wasn’t enlarged. As I mentioned, he had clear lungs and was without evidence of peripheral edema.
?? Dr. Marx:
What did you do for him‘?
0 Dr. Melick: He was placed on a cardiac monitor and three liters of oxygen by nasal cannula. We obtained an ECG (Figure 1). 0 Dr. Loeffler: Dr. Melick do you mind interpreting this ECG for us? 0 Dr. Melick: The ECG shows a narrow complex tachycardia with a rate of just over 200 BPM. There were no obvious signs of Wolfe-Parkinson-White Syndrome (WPW).
the
0 Dr. Loeffler: What happened
of
next?
Case Records features case conferences presented at teaching institutions. This section is coordinated by MD.
0736-4679190 335
$3.00 + .OO
336
?? Dr. Melick: He remained stable and we opted to try vagal maneuvers to convert him. They were unsuccessful. At that point, we thought he needed to be moved to a major resuscitation room to be converted pharmacologically. The only problem with moving him was that we had three stabbings and six major motor vehicle accidents and two ventilators in the department. We didn’t have an appropriate room. 1 paged pediatrics and they graciously offered to come down to help monitor the child. 0 Dr. Ken K&g: Did you explore what medications were available in the home including thyroid medications, cocaine, or amphetamines? 0 Dr. Meiick: We didn’t take a toxicologic history partly because he had had palpitations multiple times and his mother had a similar history. 0 Dr. Kulig: Well she may just be saying that. Was a urine toxicology screen obtained? 0 Dr. Melick: No, I didn’t order one. 0 Dr. Marx: Supraventricular tachycardias in children typically occur with a normal heart. They are brought on by exercise, flus, or colds, or just nothing in particular. That appears to be the case with this child. Less commonly, certain anatomical predispositions exist including accessory electrical pathways, Ebstein’s anomaly, and mitral valve prolapse. 0 Dr. Melick: We did obtain a chest x-ray study which was normal. [7 Dr. Loeffler: The boy was admitted to an ICU bed where he was given verapamil, 0.07 mg/kg IV push, which rapidly converted him following unsuccessful vagal maneuvers. His ECG following conversion showed a sinus rhythm at 110 BPM (Figure 2).
?? Dr.
Marx: Was verapamil not used in the emergency department because you never had a place to administer it? 0 Dr. Melick: It was too chaotic in the emergency department, and an appropriate monitoring room and personnel were unavailable. It was preferred that the patient be taken to a quiet, monitored room with oneto-one nursing coverage. 0 Dr. Loeffler: While in the intensive care unit, after converting with verapamil, the patient received a loading
Sara K. Scott
dose of 350 pg of digoxin IV. He had no complications during his admission and was discharged on the second hospital day. 0 Dr. Cantrill: Did he get started on long-term digoxin?
?? Dr. LoeMer: He was discharged on 100 pg bid of digoxin. I have asked Dr. Michael Schaffer, a pediatric cardiologist at the University of Colorado Health Sciences Center to briefly discuss issues of cardiac irregularities in children. 0 Dr. Michael Schaffer: This case presents a number of issues involving the diagnosis and management of tachycardia. When a child comes into the emergency department, the first thing you need to do is assess the child’s overall status. In children, the mechanism of the tachycardia is not of primary importance. If the rhythm is not supporting an adequate blood pressure, you need to alter it immediately. I don’t think there is really a place for IV medical management of a patient who has vascular collapse. You DC cardiovert them to stop the dysrhythmia (1,2). The chance of hurting someone by shocking them is low, even if the underlying rhythm is sinus. But, if you give the wrong drug to the wrong tachycardia, you may hurt someone. This child came in with a narrow complex tachycardia, but what if he came in with a wide complex tachycardia. In adults you assume a wide complex tachycardia is ventricular in origin until proven otherwise. You frequently hear that a wide complex tachycardia is SVT with aberrant conduction. That is just wrong most of the time. Ninety percent of wide complex tachycardias in children are ventricular tachycardia (3). This child arrived with a narrow complex tachycardia and cardiovascularly was stable. Consequently, nothing needed to be done immediately. Next you obtained his history. Does the tachycardia start and stop abruptly? If it does, you are dealing with a reentry phenomenon. Reentry can be in the atrium, in the AV node, or through an accessory bypass tract. If the tachycardia is gradual in its onset, you are dealing with an ectopic focus and it can be anywhere, high in the atrium or down in the ventricles. So history is very helpful. Seven year olds can frequently give you an accurate history, while younger children are less clear. If a history can’t be obtained, an electrocardiogram must be obtained immediately. The presenter mentioned that the original electrocardiogram showed a narrow QRS complex without a delta wave. During orthodromic reciprocating tachycardia with Wolff-Parkinson-White syndrome, you won’t see the delta wave because the delta wave is caused by anterograde conduction over the
Palpitations
in a Six-Year-Old
337
Boy
NII
INTERPRETATION DOCTOR
DATE
i
Figure 1. ECG on admission to the emergency department. accessory pathway. During the tachycardia, the electrical wavefront goes down the AV node and retrograde up
the accessory pathway. So this patient’s ECG with a narrow QRS could be consistent with Wolff-ParkinsonWhite. You can’t tell with certainty until the patient converts to sinus rhythm (1). Given that fact, you don’t want to give this child digoxin until you know the underlying mechanism. Even verapamil is in many places thought to be inappropriate for acute management of tachycardia secondary to WPW. The implied risk with both is that they may enhance the rate of conduction over the accessory pathway. With a child who is stable and has a narrow QRS tachycardia, the next thing to look for are P waves. In this child’s ECG you can’t see them (Figure 1). If his P wave rate is different than his QRS rate he’s got AV dissociation, and this would mean that he doesn’t have a reentry phenomenon using an accessory pathway. It isn’t
possible to tell in this child, but if they were present it is very strong evidence that you are dealing with a ventricular ectopic focus. If you’ve seen a child and he looks well and you’ve recorded an ECG, but you can’t see P waves, vagal maneuvers should be attempted. In a seven year old, an ice bag in the face doesn’t work very well. In children, two years old and under, you can take an ice bag and put it in their face, right over the bridge of their nose (2,4). The diving reflex is induced and this slows the heart rate (1). In little babies this technique works very well. In a seven-year-old child it usually just tends to produce more anxiety, leading to screaming and production of catecholamines. In this setting tachycardia will not break. Other vagal maneuvers can be used in children. Every emergency department has a surgical glove. Having the child blow up the surgical glove is the equivalent of a Valsalva maneuver. Another technique is to take a 30
!
:
1
:
! ; :qf :
/ i i
/ [
! i
’/ -1..I
-. _ -1,. -” I-. i-
_,._1
I ;
t
Figure 2. Postconverslon ECG.
cc syringe and lock a stopcock on the end of it. Then try to get the child to blow it off. When you demonstrate, you don’t lock it on and it easily blows off. When you put it on for the child, lock it on then have him blow. This agai.n simulates a Valsalva maneuver. Some children convert themselves by standing on their heads. If you can find the vagal maneuver that works, these children won’t have to come into the emergency department every time they get palpitations. If the child is stable, you can teach the parents and reassure them that their child won’t die suddenly. If vagal maneuvers don’t work, other electrophysiological methods can be employed. If an esophageal electrode is available (4,5), it is easy to put it down the nose so the electrode is behind the left atrium. I have paced newborn babies until enough medication is on board to prevent the dysrhythmias. If pacing doesn’t work, then pharmacologic management is necessary. Verapamil is a nice agent, but an even
better agent is adenosine (6). Adenosine creates a temporary block. Its half-life is very short, and its effect is gone in half a minute. However, it is not approved for use in the U.S. at present. Verapamil blocks the AV node. If the tachycardia involves the AV node, it is effective (2). The problem with verapamil is it is often given for the wrong tachycardias (i.e., those not involving the AV node). In the operating room or post-operative intensive care unit, the patient with tachycardia is likely to have junctional tachycardia. If verapamil is given to such a patient, the preload is reduced by vasodilitation and the patient may become hypotensive. Hypotension also occurs with verapamil use in sinus tachycardia due to fever or hypovolemia. I think a valuable drug for treating unknown tachydysrhythmias is procainamide. It treats ventricular tachycardias, supraventricular tachycardias, and automatic foci. In a situation with a hemodynamically stable
Palpitations
in a Six-Year-Old
339
Boy
patient where the patient must be treated but the underlying mechanism is not known, use procainamide.
it probably should not be used (2,7). If for some reason you think you need to use it, you must have calcium and volume expanders available.
!J Dr. Loeffler: Any questions? 0 A physician: If procainamide is given, will it cause any problems when working up the patient electrophysiologically?
?? Dr. Schaffer: Yes, but the usual procedure is to let it wear off and then take the patient for electrophysiological studies. 0 Dr. Michael Radetsky: Should verapamil be given to infants and newborns?
I-J Dr. Schaffer: The party line is not to use it. Even when administered for the right reason, the newborn myocardium is extremely sensitive to verapamil. It is much more so than the older child or adult myocardium. You need to be very, very careful and unless you are inside an electrophysiology lab, or giving it to a child who has gotten it in the past and is known to tolerate it,
0 Dr. Kulig: If this child were unstable and you wanted to cardiovert him, what preconversion agents would you use?
0 Dr. Schaffer: In terms of sedation, I would probably use ketamine, 1 mg/kg IV. Ketamine also lasts longer for cardioversion and leaves the patient amnestic for the event. You can use just about anything with which you are comfortable. I frequently use Valium@ or Versed@, 0.1-0.2 mgkg IV. Short-acting barbiturates also work well in this type of patient. For cardioversion in an unstable patient I begin with 1 watt-se&g and if unsuccessful I increase the dose (in a stepwise fashion) up to a maximum of 4 watt-set/kg. For elective cardioversion of atria1 flutter, I may begin at a lower dose of l/2 watt-se&g (2). 0 Dr. Loeffler: Thank you, Dr. Schaffer, for your very practical comments.
REFERENCES Garson A Jr, Gillette C. Dysrhythmias. In: Heart disease in infants, children and adolescents. Baltimore: Williams and Wilkins; 1989: 925-39. Wilkinson JL. Management of paroxysmal tachycardia. Arch Dis Childhood. 1983;53:945-6. Garson A Jr. Ventricular dysrhythmias. In: Gillette DC, Garson A. Jr. Pediatric cardiac dysrhythmias. New York: Grune and Stratton; 1981;319. Dick M, Campbell R. Advances in the management of cardiac arrhythmias in children. Pediatr Clin North Am 1984;3 1: 1175-95.
5. Dick M II, Scott WA, Serwer GS, et al. Acute termination of supraventricular tachyarrhythmias in children by transesophageal atrial pacing. Am J Cardiol. 1988;61:925-7. 6. Overholt ED, Rbeuban KS, Gutgesell HP, Lerman BB, Dimarco JP, Usefulness of adenosine for arrhythmias in infants and children. Am J Cardiol. 1988;61:336-40. I. Kirk CR, Gibbs JL, Thomas R, Radley-Smith R, Qureshi SA. Cardiovascular collapse after verapamil in supraventricular tachycardia. Arch Dis Childhood. 1987:62:12656.