Procedural Sedation for Cardioversion
Date First Published:
June 26, 2005
Last Updated:
October 20, 2006
Report by:
Jeremy Wood, MD, Senior Resident (Michigan State University/MERC Emergency Medicine Residency Program)
Search checked by:
Craig Ferguson, Michigan State University/MERC Emergency Medicine Residency Program
Three-Part Question:
In [patients with atrial fibrillation, atrial flutter, or paroxysmal supraventricular tachycardia requiring electrical cardioversion] are [there medications superior in safety and efficacy] in [achieving procedural sedation]?
Clinical Scenario:
An 38 year old male arrives in your emergency department complaining of palpitations and feels slightly light headed. He has never had these symptoms before and is certain that they started 1 hour prior to arrival. He is awake and alert with a blood pressure of 134/82 and a pulse of 128. His physical exam is unremarkable with the exception of tachycardia and an irregularly irregular rhythm.
Search Strategy:
Medline 1966-08/06 using the OVID interface, Cochrane Library (2006)
Search Details:
[exp Tachycardia, Ectopic Atrial/ OR exp Atrial Fibrillation/ or atrial.mp. OR exp Atrial Flutter/ OR fibrillation.mp. OR flutter.mp.
OR exp Tachycardia, Supraventricular/ OR exp Tachycardia, Atrioventricular Nodal Reentry/ OR supraventricular.mp. or exp Tachycardia, Paroxysmal/] AND [exp "Hypnotics and Sedatives"/ OR sedation.mp. OR sedat$.mp. OR hypnotic$.mp.] LIMIT to humans and English language
OR exp Tachycardia, Supraventricular/ OR exp Tachycardia, Atrioventricular Nodal Reentry/ OR supraventricular.mp. or exp Tachycardia, Paroxysmal/] AND [exp "Hypnotics and Sedatives"/ OR sedation.mp. OR sedat$.mp. OR hypnotic$.mp.] LIMIT to humans and English language
Outcome:
373 papers found, of which 7 had randomised trials comparing agents for sedation for cardioversion and were felt to be of sufficient quality to include.
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Titration of intravenous anesthetics for cardioversion: A comparison of propofol, methohexital, and midazolam. Gale DW, Grissom TE, Mirenda JV. 1993, USA | Thirty adult patients with atrial fibrillation, atrial flutter, or paroxysmal supraventricular tachycardia requiring electrical cardioversion. Patients were randomized to receive one of three study drugs: propofol, midazolam, or methohexital. |
Randomized Trial | digital-brachial pressure index (ratio of digital to brachial artery systolic blood pressures), digital temperature and in 10 patients digital artery blood flow was measured using duplex scanner. | Marginal decrease in digital-brachia pressure index after the block (19%, SD 14.6%), finger tip temperature showed mean increase of 0.8 degree celcius (SD 2.3), digital artery blood flow in 10 patients showed initial decrease in 5 to 10 minutes, but in all returned to normal by 1 hour. No one had ischemic damage to the finger | Groups slightly dissimilar at baseline. Small study, power study not done. |
| Hemodynamics | No significant difference | ||||
| Dose requirements | Propofol: 1.69 +/- 0.46 mg/kg. Methohexital: 1.07+/- 0.34 mg/kg. Midazolam: 0.16 +/- 0.06 mg/kg. | ||||
| Time to awakening | Propofol: 11.2+/- 4.4 min. Methohexital: 9.4 +/- 2.8 min. Midazolam: 33.1+/- 15.1 min. | ||||
| Adverse effects | Propofol: 2/10 patients recalled shock one hour after event. Pain on injection noted. Methohexital: One patient recalled shock. Midazolam: 5/10 patients with post-recovery confusion lasting > 10 mins. | ||||
| Sedation for cardioversion in the Emergency Department: Analysis of Effectiveness in Four Protocols. Coll-Vincent B, Xavier S, Fernandez C et al. 2003, USA | Thirty two hemodynamically stable adult patients undergoing cardioversion in the ED. These patients were randomized receive etomidate, propofol, midazolam, or midazolam followed by flumazenil. |
Randomized control trial | Induction time | Propofol: 50 (30-100) seconds. Etomidate: 90 (25-120) sec. Midazolam: 120 (30-180) sec. Midazolam + Flumazenil: 112 (30-350) sec. | Small study, no power study done |
| need for further injection of local anaesthetic, need for tourniquet and ischemic complications. | Need for tourniquet (20/29 of plain lignocaine group vs 9/31 of adrenaline group, p<0.002), need for further anaesthetic (5/29 of plain lignocaine vs 1/31 of adrenaline group, p=0.098), no ischemic complications in the adrenaline group | ||||
| Hemodynamics | No significant differences | ||||
| Time to awakening | Propofol: 8 (3-15) min. Etomidate: 9.5 (5-11). Midazolam: 21 (1-42). Midazolam + Flumazenil: 3 (2-5). | ||||
| Adverse effects | Propofol: 1/9 broncho-spasm. Etomidate: 4/9 myoclonus, 1 bronchospasm, 4 pain at injection site, 2 cough Midazolam: 3 dizziness Midazolam + Flumazenil: 5 resedation | ||||
| Anaesthesia for cardioversion: A comparison of propofol and thiopentone Valtonen, M; Kanto, J; Klossner, J 1988, Finland | 35 patients undergoing elective cardioversion due to atrial fibrillation. 30 patients received one cardioversion. 5 patients were cardioverted twice in the study period and received the other form of sedation the on the second occasion. | Patients were randomised to receive either 2.5mg/kf propofol or 5mg/kg thipentone and then observed until unresponsive to speech. The patient was then given up to 3 DC shocks. | Need for tourniquet, degree of analgesia, duration of analgesia and ischemic damage to the digit | Need for tourniquet (Gp A= 20%, Gp B= none), pain score at 1 hour (Gp A=4.1 and Gp B=1.4), duration of analgesia ( Gp A=2.4 hrs, Gp B=4.6 hrs), No case of ischemic damage to finger | Small group. Much of the data provided in form of graphs so unable to extract it to put in table form. |
| Induction time | 72.0+/-20.0s for propofol vs. 60.3+/-13.0s for thiopentone | ||||
| Anatomical, radiographic and fucntional results | 158 patients successfully treated | ||||
| Time to orientation - from end of procedure | 7.7+/-2.9 min for propofol vs. 6.5+/-4.4 min for thiopentone. | ||||
| Successful cardioversion | 11/15 for propofol, 13/15 for thiopentone. | ||||
| A Comparison of Etomidate and Thiopental Anesthesia for Cardioversion Ford, S; Maze, M; Gaba, D 1991 USA | 16 male patients undergoing elective cardioversion for atrial fibrillation or flutter. | Patients were randomised to receive 0.2% etomidate or 2.5% thiopental. The drugs were administered at 2ml every 15 sec until the patient no longer responded to verbal commands. Observer blinded to drug received. | Change in mean heart rate. | Etomidate decreased the mean heart rate by 5%, thiopental increased it by 7%. | Small study. |
| Digital ischemic complications | Etomidate decreased MAP by 4%, Thiopental decreased it by 3%. | ||||
| Change in mean arterial pressure | 1 in each group. | ||||
| Failure of cardioversion | 1 in each group. | ||||
| Pt recall of cardioversion | Etomidate 1.8±0.2; Thiopental 2.3±0.2 | ||||
| Time of onset of adequate sedation (min) | Etomidate 7.4±1.2; Thiopental 10.1±3.5 | ||||
| Orientation time (min) | Etomidated 3/8 pts; Thiopental 0/8 pts. | ||||
| Myoclonus | |||||
| Anesthesia for Elective Cardioversion: A Comparison of Four Anesthetic Agents Canessa, R; Lema, G; Urzua, J; Dagnino, J; Concha M 1991 Chile | 44 patients with atrial flutter or fibrillation attending for elective cardioversion. All patients received 1.5µg/kg fentanyl in addition to the sedative. | Patients randomised by last digit of case-note number to one of 4 agents for sedation. 12 pts received 3mg/kg thiopental (T), 10 patients received 0.15mg/kg etomidate (E), 12 patients received 1.5mg/kg propofol (P) and 10 patients received 0.15mg/kg midazolam (M). | Change in mean systolic blood pressure. | T decreased by 19%, E no significant difference, P decreased by 29%, M decreased by 19%. | Small groups. Poor method of randomisation (treating physician knows which drug patient will receive before decides whether or not to recruit them). Not clear how randomised between four outcomes using ten digits. |
| digital gangrene from use of adrenaline in finger | Total 21 cases of digital gangrene reported involved use of adrenaline, all from early 20th century. Analysis of individual cases did not support adrenaline itself as the cause. Inappropriate mixing of adrenaline, inappropriate use of tourniquet, use of hot soaks, infection, and use of large volume of anaesthetic were associated the cases. | ||||
| Successful cardioversion | T 12/12; E 7/10; P ?11/12 (given as 90%); M 9/10 | ||||
| Mean induction time in seconds (range) | T 31(10-50); E 34 (12-49); P 17 (10-40); M 68 (30-220) | ||||
| Myoclonus | T 0; E 3; P 0; M 0 | ||||
| Apnoea (loss of ventilatory effort >30sec) | T 2/12; E 1/10; P 7/12; M 1/10 | ||||
| Diazepam or midazolam for external DC cardioversion (The DORM Study) Mitchell, A; Chalil, S; Boodhoo, L; Bordoli, G; Patel, N; Sulke, N 2003 UK | 141 patients attending one unit for elective cardioversion of an atrial tachyarrhythmia who had not been cardioverted under sedation previously. | Patients were randomised to receive diazepam (5-10mg bolus followed additional 5-10mg doses every minute up to a maximum of 70mg) or midazolam (5mg bolus plus 1-2mg every minute up to a maximum of 30mg). | Successful cardioversion | 87% of pts receiving diazepam vs. 89% of patients receiving midazolam. | Only patients blinded to drug received. |
| Digital artery blood flow. | Statistically significant drop in blood flow at 10 minutes after the block in all subjects. In all cases blood flow returned to normal by 60 to 90 minutes.Vasoconstrictive effect of adrenaline is not persistent. | ||||
| Episode of hypotension (decrease in systolic BP >20mmHg or systolic BP <100mmHg. | 7% of pts receiving diazepam vs. 20% of patients receiving midazolam. | ||||
| Episode of oxygen desaturation (<99% despite supplementary oxygen) | No patients receiving diazepam vs. 3% of patients receiving midazolam. | ||||
| Time for adequate sedation (min) | Diazepam 6.5±3.4 vs. midazolam 5.0±3.4. | ||||
| Time till awake and orientated (min) | Diazepam 39±24 vs. midazolam 77±46. | ||||
| Pt able to recall events | 1 in diazepam group, none in midazolam group. | ||||
| Ambulatory Electrical External Cardioversion with Propofol or Etomidate Herregods, L; Bossuyt, G; Baerdemaeker, L; et al 2003 Belgium | 34 patients with atrial arrhthmias who were scheduled to receive repetitive electrical cardioversion. 9 patients were not successfully cardioverted at the first or second session and so only 25 patients were analysed. | Patients randomised in prospective double-blinded study to receive either 0.2mg/kg etomidate or 1mg/kg propofol. The patients were then cardioverted again at least one week later using the alternative agent. Patients who were not successfully cardioverted by four attempts at either session were excluded. | Digital gangrene | 48 cases of digital gangrene, only 21 involved use of adrenaline. None of the cases indicate adrenaline solely as the cause of gangrene. Other factors like high concentration of adrenaline, use of older agents, excessive volume of injection, prolonged use of tourniquet, infection and use of hot soaks | No information about induction times. Small group. |
| Required manually assisted ventilation. | 7/25 etomidate vs. 5/25 propofol. | ||||
| Time to opening eyes (sec) | 6.1±2.0 etomidate vs 4.7±1.2 propofol. | ||||
| Myoclonus | 6/25 etomidate vs 0/25 propofol. | ||||
| Signficant decrease in BP | No patients in either group. |
Author Commentary:
All of the agents used in these studies had relatively short time of onset and short duration of action with the exception of the benzodiazepines which were considerably longer for both. All anaesthetic agents have the potential to cause hypotension though this did not cause any serious adverse events in any of the patients who participated in these studies. Etomidate may cause less hypotension than other agents but does cause myoclonus in some patients.
Bottom Line:
Propofol, methohexital, thiopentone and etomidate all appear to be good choices for procedural sedation for patients requiring electrical cardioversion for atrial fibrillation, atrial flutter, and paroxysmal supraventricular tachycardia. Midazolam and diazepam have a significantly longer recovery time, and can produce confusion in the recovery period as well. They should be considered a second line agents for sedation for cardioversion.
Level of Evidence:
Level 3: Small numbers of small studies or great heterogeneity or very different population
References:
- Gale DW, Grissom TE, Mirenda JV.. Titration of intravenous anesthetics for cardioversion: A comparison of propofol, methohexital, and midazolam.
- Coll-Vincent B, Xavier S, Fernandez C et al.. Sedation for cardioversion in the Emergency Department: Analysis of Effectiveness in Four Protocols.
- Valtonen, M; Kanto, J; Klossner, J. Anaesthesia for cardioversion: A comparison of propofol and thiopentone
- Ford, S; Maze, M; Gaba, D. A Comparison of Etomidate and Thiopental Anesthesia for Cardioversion
- Canessa, R; Lema, G; Urzua, J; Dagnino, J; Concha M. Anesthesia for Elective Cardioversion: A Comparison of Four Anesthetic Agents
- Mitchell, A; Chalil, S; Boodhoo, L; Bordoli, G; Patel, N; Sulke, N. Diazepam or midazolam for external DC cardioversion (The DORM Study)
- Herregods, L; Bossuyt, G; Baerdemaeker, L; et al. Ambulatory Electrical External Cardioversion with Propofol or Etomidate