Orthogonal electrical cardioversion in atrial fibrillation refractory to biphasic shocks: a case series

Abstract Background Biphasic waveform shock has been established as the standard method for cardioversion of atrial fibrillation (AF). Depending on various factors, standard electrical cardioversion for AF may be unsuccessful in some cases, even with biphasic shocks. Case summary We report the safety and efficacy of orthogonal electrical cardioversion (OECV) as an alternative in patients with paroxysmal AF refractory to standard biphasic electrical cardioversion after up to three subsequent shocks of increasing energy and/or two or three initial shocks with maximum energy of 200-Joules. Shocks were delivered with two external defibrillators via two sets of adhesive electrode pads to apply two perpendicular electrical vectors in a simultaneous-sequential mode in antero-lateral and antero-posterior configuration. Five patients, mean age 54.4 ± 11, three with hypertensive heart disease and a body mass index 27.2 ± 2 kg/m2. All individual mean impedance before OECV was 79 ± 5 Ω with a mean peak current applied of 22 ± 4.5 A. Restoration of sinus rhythm with OECV was achieved acutely and sustained in all five patients. No patients developed haemodynamic instability or thromboembolic events. Discussion Double simultaneous shocks in an orthogonal configuration could theoretically decrease the defibrillation threshold through the ability of sequential pulses applying a more efficient and uniform current density. OECV using lower/medium energy may be another useful rescue strategy in AF refractory to standard biphasic shocks.

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Transient appearance of Brugada-like Type 1 electrocardiogram pattern immediately after biphasic synchronized electrical cardioversion for atrial fibrillation: a case series

European Heart Journal - Case Reports ◽

10.1093/ehjcr/ytz198 ◽

2019 ◽

Author(s):

Khalid A S Abdalla ◽

Antonio Sorgente ◽

Pedro Brugada

Keyword(s):

Atrial Fibrillation ◽

Safety Issue ◽

Case Series ◽

Electrical Cardioversion ◽

Common Finding ◽

St Segment Elevation ◽

Case Summary ◽

St Segment ◽

Number Of Patients

Abstract Background ST-segment deviation post-electrical cardioversion is a common finding amongst a significant number of patients. However, the mechanism by which this phenomenon occurs and its clinical implications are not fully understood. Case summary Four patients presented to our department with complaints of palpitations. They were found to have atrial fibrillation and were cardioverted using a synchronized direct current shock at 200 J. However, their telemetry immediately after the shock showed transiently an ST-segment elevation resembling Brugada Type 1 pattern. All telemetries normalized within 6 s from cardioversion. Discussion Through this report, we aim to raise mild concern about a possible safety issue related to synchronized electrical cardioversion with electrodes positioned in an anteroposterior fashion. Also, we try to give a pathophysiological explanation to this finding on the base of the knowledge accumulated through the years on Brugada syndrome.

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Impact of electrical shock waveform and paddle positions on efficacy of direct current cardioversion for atrial fibrillation

Medicina ◽

10.3390/medicina44090085 ◽

2008 ◽

Vol 44 (9) ◽

pp. 665 ◽

Cited By ~ 7

Author(s):

Giedrė Stanaitienė ◽

Rūta Babarskienė

Keyword(s):

Atrial Fibrillation ◽

Success Rate ◽

Direct Current ◽

Left Ventricular ◽

Electrical Cardioversion ◽

Left Ventricular Ejection ◽

Ventricular Ejection Fraction ◽

Direct Current Cardioversion ◽

Biphasic Waveform ◽

Recurrent Atrial Fibrillation

Objective. Direct-current electrical cardioversion is the main method for the conversion of atrial fibrillation. Its success depends on many factors. In several studies, biphasic shock waveforms have been demonstrated to be superior to monophasic shocks for termination of atrial fibrillation; however, information about impact of paddle position is controversial. Initial energy level is an object of discussions. The aim of the study was to compare a truncated exponential biphasic waveform with monophasic damped sine waveform and antero-lateral with antero-posterior paddle positions for cardioversion of atrial fibrillation, to determine its impact on early reinitiation of atrial fibrillation. Material and methods. A total of 224 consecutive patients with atrial fibrillation underwent electrical cardioversion with biphasic (Bi, n=112) or monophasic (Mo, n=112) shock waveform in a randomized fashion. The position of hand-held paddle electrodes was randomly selected in both groups to be anterior-lateral and anterior-posterior. Energies used were 100–150–200–300–360 J (Bi) or 100–200–300–360 J (Mo). If monophasic shock of 360 J was ineffective, we used biphasic shock of 360 J. Early recurrent atrial fibrillation (ERAF) was defined as a relapse of atrial fibrillation within 2 min after a successful cardioversion, acute recurrent – within 24 h. Results. Two study groups (Bi vs Mo) did not differ with regard to age, body mass index, duration of AF episode (mean 98±147 days for the Bi group and 80±93 days for the Mo group, P=0.26), underlying heart disease, left atrial diameter, left ventricular ejection fraction. In the Mo group, more patients used amiodarone (59.82% vs 41.97%, P=0.002), in the Bi group more patients used propafenone (16.07% vs 8.93%, P=0.033). Cardioversion success rate was 97.32% in the Bi group and 79.46% in the Mo group (P<0.001). After biphasic shock of 360 J in Mo group, the cumulative success rate was 99.11%. Mean delivered energy and mean number of shocks were significantly lower in the Bi group (198.5±204.4 J, 1.5±0.9 shocks vs 489.1±464.2 J, 2.4±1.5 shocks). The efficacy of first shock was 66.96% in the Bi group and 37.5% in the Mo group (P<0.0001). Incidence of ERAF was 4.46% in both groups. Paddle position had no impact on efficacy of cardioversion and ERAF. Conclusions. For the cardioversion of atrial fibrillation, biphasic shock waveform has a higher success rate than monophasic shock waveform. We did not observe the influence of paddle positions on efficacy of cardioversion. Shock waveform and paddle position had no impact on ERAF. We recommend starting with biphasic energy of 150 J and monophasic of not less than 200 J for cardioversion of atrial fibrillation.

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