S-10
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SMART algorithm in dual chamber
ICD for supraventricular tachycardia detection
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Amiran Sh. Revishvili, Max
Schaldach*, Tran Thong*.
Bakulev Institute of Cardiovascular Surgery, Moscow, Russia, *Institute for
Biomedical Engineering, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen,
Germany
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Abstract
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Background. Inappropriate ventricular
shocks due to episodes of supraventricular tachycardia have been reported in up to 25% of
patients. An atrioventricular discrimination algorithm is needed in dual chamber
implantable cardioverter-defibrillators to reduce the occurrences of these inappropriate
shocks.
Methods. An atrioventricular discrimination algorithm, SMART
Detection, has been developed to differentiate between episodes of ventricular tachycardia
and supraventricular tachycardia. It relies on the concept that the chamber with the
higher rate is the origin of the tachycardia. The ventricular rate stability criterion is
also used to detect a ventricular tachycardia during an episode of supraventricular
tachycardia. The SMART Detection algorithm has been implemented in the Biotronik Phylax AV
dual chamber implantable cardioverter-defibrillators. The original SMART Detection has
been improved recently by adding active detection for the case of 1:1 atrioventricular
conduction.
Results. Ten patients were implanted with Phylax AV's at the Bakulev
Institute. Analysis of stored dual chamber intracardiac electrograms indicate that all
episodes of ventricular tachycardias and ventricular fibrillations were terminated
following appropriate therapies. No episode of atrial flutter or atrial fibrillation was
treated even though the majority of patients has a history of supraventricular
tachycardias. In one patient, an episode of sinus tachycardia was inappropriately treated.
Increasing the sudden onset criterion was sufficient to prevent recurrence of
inappropriate treatment.
To avoid the necessity of setting the, not very reliable, sudden onset criterion an active
detection procedure has been developed. Isolated premature ventricular stimuli were used
to test the hypothesis of ventricular tachycardia with retrograde atrial conduction in the
case of 1:1 atrioventricular rate. This improvement to SMART Detection has been
successfully tested in an animal model.
Conclusion. The SMART Detection algorithm with its active detection
improvement in case of 1:1 atrioventricular rate should prove to be an effective
atrioventricular discrimination algorithm in dual chamber implantable
cardioverter-defibrillators which will offer freedom from unnecessary shocks in response
to supraventricular tachycardias.
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Key Words
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Implantable cardioverter defibrillator –
function, indications
supraventricular arrhythmias, atriventricular discrimination algorithm, SMART algorithm,
OA
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