Biomedical subjects

Giedre Stanaitiene

Publications and source records attributed to Giedre Stanaitiene.

2 recordsLinked to original sources

PubMed2006

Anterior-posterior versus anterior-lateral electrode position for biphasic cardioversion of atrial fibrillation.

OBJECTIVE: The aim of the study was to assess if the anterior-posterior electrode position for the conversion of atrial fibrillation using biphasic waveform shocks is more effective and needs less energy compared with the anterior-lateral position. BACKGROUND: In several studies, anterior-posterior electrode position has been demonstrated to be superior to anterior-lateral position for the termination of atrial fibrillation using monophasic waveform shocks, but data regarding biphasic shocks are still emerging. PATIENTS AND METHODS: Our prospective, randomized study enrolled 103 consecutive patients with atrial fibrillation who were referred for elective cardioversion. The electrode position was randomly selected to be anterior-lateral (n=55) and anterior-posterior (n=48). A step-up protocol of 100, 150, 200, and 300 J biphasic truncated exponential waveform shocks was used. RESULTS. Two groups with different paddle position were compared. There was no difference in age, gender, body mass index, ejection fraction, or left atrial size between the groups. Sinus rhythm restoration failed only in one patient in each group. Energy of 100 J was sufficiently effective in most patients in both groups. CONCLUSIONS: The anterior-posterior electrode position during transthoracic cardioversion using biphasic waveform shocks has no advantages compared with more comfortable and common anterior-lateral position.

Aged↗

PubMed2005

[Electrical defibrillation and cardioversion].

Defibrillation and cardioversion are techniques in which a short electric impulse is administered to the heart in order to restore its normal rhythm. During cardioversion electric impulse is synchronized to the QRS on electrocardiogram. During defibrillation electric current passes through the heart in any phase of electric heart cycle. This mode of treatment is rather new - Lown et al. started to use it in a clinical practice in 1962. During defibrillation or cardioversion electric current goes from negative to positive electrode of defibrillator and passes the heart on its way. This induces transmembrane potential in myocardium cells and results in synchronic depolarization of all myocardium. The pathophysiology of defibrillation is explained by critical mass hypothesis as well as the upper limit of vulnerability hypothesis. The success of defibrillation depends on many factors, such as the location and size of electrodes, the type of defibrillator, the morphology of electric impulse, transthoracic impedance, the type and duration of arrhythmia. This procedure can be performed only on unconscious patient. The possible complications of the procedure can be disturbances in heart rhythm and conduction, the changes in arterial blood pressure, the damage to the myocardium, embolia, pulmonary edema and others. This article describes the mechanism of action of defibrillation and cardioversion, indications for this procedure, the technique and methods of defibrillation and cardioversion, the factors, responsible for the efficacy of the procedure and possible complications of defibrillation.

Defibrillators↗