Atrial fibrillation: DC cardioversion guided by transesophageal echocardiography led to fewer bleeds.

Clinical bottom line (level 1b)

  1. Patients with atrial fibrillation who received DC cardioversion based on transesophageal echocardiography results compared with standard therapy were less likely to have a haemorrhage (NNT = 39 at 8 weeks) .
  2. There was no clear difference in embolic events, mortality or number of patients still in sinus rhythm after 8 weeks.
Klein et al: New England Journal of Medicine 2001; 344 : 1411-1420
Expires November 2003

The study

Unblinded ?concealed randomised trial with intention-to-treat
Setting: 70 acute hospitals, USA

1222 patients (aged mean 64, 67% male) with atrial fibrillation lasting more than 2 days or atrial flutter and a documented history of AF.

Excluded if
  • women of childbearing potential
  • patients who might need procedures requiring the discontinuation of study medication
  • contraindications to warfarin or transesophageal echocardiography
  • aged < 18
  • atrial flutter and no history of AF
  • haemodynamic instability
  • on long-term warfarin therapy (> 7 days)

    Control Group: (n = 603, 603 analysed): conventional treatment: warfarin for 3 weeks, followed by DC cardioversion, then warfarin for another 4 weeks
    Experimental Group: (n = 619, 619 analysed): transesophageal echocardiography: therapeutic anticoagulation with heparin or warfarin. No thrombus detected - DC cardioversion, and warfarin for 4 weeks. Thrombus detected - warfarin for 3 weeks, then repeated TEE. If no thrombus then, DC cardioversion and warfarin for 4 weeks. If thrombus, no DC cardioversion and warfarin for 4 weeks.
    Patients could take anti-arrhythmic medication during the study.
    100% followed for 8 weeks
    Outcome notes:
    • embolic event : stroke, transient ischaemic attack, peripheral embolism

    The evidence

    Outcome Time to outcome CER EER RRR
    (95% CI)    		 ARR
    (95% CI)    		 NNT
    (95% CI)
    embolic event 8 weeks 3
    (0.50%)    		 5
    (0.81%)    		 -62%
    (-580% to 61%)    		 -0.31%
    (-1.21% to 0.59%)    		 -320
    (NNT = 170 to infinity;
    NNH = 83 to infinity)
    haemorrhage 8 weeks 33
    (5.47%)    		 18
    (2.91%)    		 47%
    (7% to 70%)    		 2.56%
    (0.32% to 4.81%)    		 39
    (21 to 320)
    death 8 weeks 6
    (1.00%)    		 15
    (2.42%)    		 -140%
    (-520% to 5%)    		 -1.43%
    (-2.88% to 0.02%)    		 -70
    (NNT = 5200 to infinity;
    NNH = 35 to infinity)
    in sinus rhythm 8 weeks 304
    (50.4%)    		 326
    (52.7%)    		 -4%
    (-16% to 6%)    		 -2.25%
    (-7.85% to 3.35%)    		 -44
    (NNT = 30 to infinity;
    NNH = 13 to infinity)

    Comments

    1. 69% of TEE patients had early cardioversion (at a mean of 3 days) compared with 55% of conventiona treatment patients (at a mean of 30 days)
    2. 14% of 549 patients who underwent TEE had a right or left heart thrombus.
    3. There was no clear difference in major haemorrhage between the two groups.
    4. The study was too small to show any difference in embolic events or mortality between the two groups.

    Citation

    1. Klein AL, Grimm RA, Murray RD, et al: use of transesophageal echocardiography to guide cardioversion in patients with atrial fibrillation (ACUTE). New England Journal of Medicine 2001; 344 : 1411-1420
    Search Terms: from ACP Journal Club
    Contributor: Chris Ball, November 2001
    Reviewer:

    Clinical Question.
    Patient atrial fibrillation
    Intervention or Exposure DC cardioversion determined by transesophageal echocardiography
    Comparison standard therapy
    Outcome embolism, haemorrhage, death, sinus rhythm