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Treatment injury case study
8
October 2011 – Issue 38
Sharing information to enhance patient safety
Failure to prescribe
anticoagulation
EVENT: INJURY: Embolic stroke
Case Study
Raewyn, a 52-year-old, saw her GP after having episodes of heart palpitations
and shortness of breath for several months. Raewyn was an ex-smoker
whose hypertension had been treated with bendrofluazide. She took no other
medications.
Her GP performed an ECG tracing of her heart,
which showed atrial fibrillation. He referred her
to the emergency department, where an initial
review was carried out before Raewyn was seen
by a cardiologist.
The cardiologist noted that Raewyn’s
exercise tolerance had been declining due to
breathlessness in the previous few months.
An ECG and echocardiogram were performed,
Key points
• The increased risk of
thromboembolism following
cardioversion is due to atrial
stunning, which can last for several
weeks
• Anticoagulation is vital before
elective cardioversion for atrial
fibrillation that has persisted for
more than 48 hours, or that has
been present for an unknown
duration
• Anticoagulation should be
continued for at least four weeks
following successful cardioversion,
even where transoesophagealguided cardioversion has excluded
pre-existing atrial thrombus.
369206-ACC6059-Press.indd 1
and she was diagnosed with recent onset atrial
fibrillation due to bi-atrial enlargement from
longstanding hypertension.
The cardiologist booked Raewyn for electrical
cardioversion to treat her atrial fibrillation
and ordered that a trans-oesophageal
echocardiogram (TOE) be carried out before the
procedure to check for existing cardiac thrombus.
The results of the TOE were normal and a
successful cardioversion was performed
under the same sedation and with heparin
anticoagulation. Raewyn was discharged with a
prescription for flecainide CR 200 milligrams to
keep her heart in sinus rhythm, but no warfarin
was prescribed.
Nine days later Raewyn was admitted to hospital
with a sudden left-sided hemiparesis. A CT scan
of her head showed changes indicating a right
middle cerebral artery infarct. It was discovered
that Raewyn had not received anticoagulation
post treatment and a treatment injury claim was
lodged with ACC.
Raewyn’s claim was assessed with assistance
from an external cardiology advisor, and it was
determined that the stroke should have been
prevented through the use of post-cardioversion
anticoagulation. The claim was accepted
and ACC was able to assist with Raewyn’s
rehabilitation.
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Case study
Expert Commentary
Phillip Matsis FRACP, FCSANZ
The increased risk of thromboembolism following
cardioversion is well known, particularly when
patients are not anticoagulated before, during or
after the procedure.
Most emboli occur within the first week after
cardioversion and usually arise from pre-existing
mural thrombus. However, some patients develop
de novo thrombi as a result of atrial stunning.
Atrial stunning manifests as persistent depression
of left atrial systolic function despite electrical
sinus rhythm. It occurs regardless of whether
the procedure was electrical, pharmacological or
spontaneous cardioversion. The degree of stunning
appears to be greater after electrical reversion, but
there is no correlation to the amount of energy used.
Stunning is more profound and persistent in the
left atrial appendage than in the left atrium. It
sometimes lasts for several weeks after a successful
cardioversion, prolonging the risk of thrombi
development.
The longer a patient is in atrial fibrillation, the
longer the left atrial dysfunction will persist. If atrial
fibrillation has been present for less than two weeks,
full recovery of left atrial function is usually seen
within 24 hours.
In patients who have experienced atrial fibrillation
for two to six weeks, recovery can take a week, and
in cases of prolonged atrial fibrillation recovery can
take as long as a month. This gradual recovery of
atrial function could explain why the majority of
embolic events occur within the first 10 days after
cardioversion.
International guidelines agree that oral
anticoagulation is vital before elective cardioversion
for atrial fibrillation that has persisted for more than
48 hours, or that has been present for an unknown
duration.
Given the risks posed by atrial stunning, this
anticoagulation should be continued for at least four
weeks afterwards.
Transoesophageal-guided cardioversion can
be used as an alternative to pre-cardioversion
anticoagulation where there is no thrombus in the
left atrium or left atrial appendage. However, oral
anticoagulation should still be used for four weeks
following successful cardioversion.
Following these evidence-based guidelines is critical
in order to reduce the risk of stroke due to atrial
stunning.
References
Berger M, Schweitzer P. Timing of thromboembolic events after electrical
cardioversion of atrial fibrillation or flutter: a retrospective analysis. Am J Cardiol
1998; 82(12):1545-1547
European Society of Cardiology (ESC) Task Force for the Management of Atrial
Fibrillation. Guidelines for the management of atrial fibrillation. Eur Heart J 2010;
31:2369-2429
Manning WJ, Silverman DI, Katz SE et al. Impaired left atrial mechanical function
after cardioversion: relation to the duration of atrial fibrillation. J Am Coll Cardiol
1994; 23(7):1535-1540
Melduni RM, Ammash NM, Callahan MJ et al. Severe left atrial appendage
stunning after electrical cardioversion of AF. Circulation 2008; 118:e699-e700
Mann LS, Curtis AB, January CT et al. 2011 ACCF/AHA/HRS focused update on the
management of patients with atrial fibrillation (updating the 2006 guideline):
a report of the American College of Cardiology Foundation/American Heart
Association Task Force on Practice Guidelines. J Am Coll Cardiol 2011; 57(2):223242
Claims information
Between 1 July 2005 and 30 June 2011 ACC received 381 treatment injury claims for
cerebrovascular accidents and haemorrhage, of which 295 (77%) were accepted.
The most common causes were the effects of medications (particularly warfarin),
angiography and cardiothoracic surgery. Delays and failures in diagnosis and
treatment, medication prescribing issues and cardioversion collectively accounted
for 24 accepted claims.
The most common reason for declining claims was that no causal link could
be established between the injury and treatment from a registered health
professional, and that the injury was wholly or substantially caused by the client’s
underlying health conditions.
How ACC can help your patients following treatment injury
Many patients may not require assistance following their treatment injury.
However, for those who need help and have an accepted ACC claim, a
range of assistance is available, depending on the specific nature of the
injury and the person’s circumstances. Help may include things like:
About this case study
•
•
This case study is based on information amalgamated from a number of
claims. The name given to the patient is therefore not a real one.
•
contributions towards treatment costs
weekly compensation for lost income (if there’s an inability to
work because of the injury)
help at home, with things like housekeeping and childcare.
No help can be given until a claim is accepted, so it’s important to
lodge a claim for a treatment injury as soon as possible after the
incident, with relevant clinical information attached. This will ensure
ACC is able to investigate, make a decision and, if covered, help your
patient with their recovery.
ACC6059 October 2011 ©ACC 2011
369206-ACC6059-Press.indd 2
Printed in New Zealand on paper sourced from well-managed
sustainable forests using oil free, soy-based vegetable inks.
The case studies are produced by ACC’s Treatment
Injury Centre, to provide health professionals with:
•
•
an overview of the factors leading to treatment injury
expert commentary on how similar injuries might be avoided in
the future.
The case studies are not intended as a guide to treatment injury cover.
Send your feedback to: [email protected]
29/09/11 5:04 PM