Waveform optimization for internal cardioversion of atrial fibrillation

Towards Low Energy Atrial Defibrillation

“…However, the use of IAD’s for the treatment of AF has not yet achieved critical acceptance; predominately due to the impact of unit automaticity on the patients quality of life and the lack of patient tolerance to the discomfort produced by high energy shocks [ 11 , 12 ]. Recent publications indicate that the further advancement of internal cardioversion for AF may therefore result from two specific lines of enquiry: (i) optimisation of the defibrillation shock impulse to achieve the lowest energy necessary to successfully cardiovert a patient (less than 1 J could potentially negate the need for patient sedation) and (ii) investigation of passive (battery free) implantable atrial defibrillators that can facilitate AF arrhythmia detection and cardioversion under controlled circumstance in a non-acute care (out-of-hospital) setting [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. In respect of the optimisation of electrical shock waveforms to achieve a defibrillation threshold of <1 J, transthoracic impedance (TTI) is a key determinant in the success of both atrial and ventricular defibrillation; due to the fact that cardioversion outcome highly correlates to the current vector delivered to the cardiac substrate.…”

“…However, there remains a paucity of studies examining the correlation of the intracardiac impedance (DC impedance, dynamic impedance and waveform spectral content) during internal atrial defibrillation to clinical outcomes. In addition, recent publications have indicated that multiple low energy intracardiac shocks may give rise to lower cardioversion thresholds [ 18 , 19 , 20 , 21 , 22 , 23 ] thereby significantly minimising patient discomfort. Yet again, a paucity of studies comparing the efficaciousness of such protocols exists.…”

“…In respect of the potential for passive (battery free) implantable defibrillator technologies to enable treatment in a non-acute care setting, the concept has several obvious merits; the issue of implant automaticity and inappropriate shocks is resolved (thereby addressing the potential quality of life associated issues previously identified) while the need for repeat surgery to replace batteries over the lifetime of the patient is entirely eliminated. Consequently, low-energy cardioversion using passive implantable defibrillator technology offers the potential for the development of AF treatment modalities and protocols that could be safely delivered in a non-acute (out-of-hospital) care setting; thereby eliminating the need for repeated hospitalisation and significantly reducing the long term cost burden associated with treatment [ 20 , 25 ].…”

Denoising and Automated R:peak Detection in the ECG Using Discrete Wavelet Transform

“…The real ECG data was recorded from thirty fully anti-coagulated patients with persistent AF, who would clinically benefit from external DC cardioversion. Exclusion criteria and complete medical procedure were as previously described by Kodoth et al [8]. The data was split into two subsections; AF beats which are those prior to successful cardioversion and NSR beats which are those from patients after they have been successfully cardioverted.…”

Assessment of Atrial Fibrillation Organization During Internal Electrical Cardioversion Using Sample Entropy

“…In a recent study to compare the safety and efficacy of low tilt monophasic vs. biphasic waveforms with the PIAD device [11] a step-up voltage protocol (50-100-150-200-240-280 and 300V) was used and ECG lead II signal recorded. However the AF organization during the whole process of multiple shocks with PIAD low-tilt waveforms has not yet been evaluated.…”