Relationship of Natriuretic Peptides with Left Atrial Structure and Function within 1 Month after Electrical Cardioversion in Patients with Persistent Atrial Fibrillation.

Atrial fibrillation (AF) despite the absence of heart failure is related to increased levels of natriuretic peptides (NPs). NPs have not been widely investigated in relation to left atrium (LA) function after sinus rhythm (SR) restoration and duration of AF. The aim of the study was to determine the changes of NPs levels and to define their relation with LA phasic function after electrical cardioversion (ECV). Methods. The study included 48 persistent AF patients with restored SR after ECV. NT-proANP and NT-proBNP were measured for all patients before the ECV. LA phasic function (reservoir, conduit, and pump phases) was assessed using echocardiographic volumetric analysis within the first 24 hours after ECV. Patients were repeatedly tested after 1 month in case of SR maintenance. Results. After 1 month, SR was maintained in 26 (54%) patients. For those patients, NT-proBNP decreased significantly (p=0.0001), whereas NT-proANP tended to decrease (p=0.13). Following 1 month after SR restoration, LA indexed volume decreased (p=0.0001) and all phases of LA function improved (p=<0.01). Patients with AF duration < 3 months had lower NT-proANP compared to patients with AF duration from 6 to 12 months (p = 0.005). Higher NT-proANP concentration before ECV was associated with lower LA reservoir function during the first day after SR restoration (R=-0.456, p=0.005), whereas higher NT-proBNP concentration after 1 month in SR was significantly related to lower LA reservoir function (R=-0.429, p=0.047). Conclusions. LA indexed volume, all phases of LA function, and NT-proBNP levels improved significantly following 1 month of SR restoration. Preliminary results suggest that higher baseline NT-proANP levels and higher NT-proBNP for patients with maintained SR for 1 month are related to lower LA reservoir function. The longer duration of persistent AF is associated with higher NT-proANP concentration.

Surgical treatment of ventricular septal defect following myocardial infarction: a case report.

Ventricular septal defect after myocardial infarction is a rare but often life-threatening mechanical complication. The keys of management are a prompt diagnosis of ventricular septal defect and an aggressive approach to stabilize patient's hemodynamics. Invasive monitoring, judicious use of inotropes and vasodilators, and an intra-aortic balloon pump are recommended for the optimal support of patient's hemodynamics. The best results are achieved if optimally medically managed patients survive at least 4 weeks before elective surgery necessary for scar formation in a friable infarcted tissue. We report a case of acute myocardial infarction complicated by the rupture of ventricular septum. Instead of attempting an immediate surgical closure of ventricular septal defect, the postponed surgery was successfully performed 3 weeks after the occurrence of ventricular septal defect. Preoperatively, clinical and hemodynamic conditions of the patient were maintained stable with the support of an intra-aortic balloon pump and inotropes.

[Impact of electrical shock waveform and paddle positions on efficacy of direct current cardioversion for atrial fibrillation]. / Elektros impulso formos ir elektrodu pozicijos itaka elektrinei kardioversijai nutraukiant priesirdziu virpejima.

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.

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.

[Electrical defibrillation and cardioversion]. / Elektrine sirdies defibriliacija ir kardioversija.

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.