A distributed simulation method of electric field based on the atrial defibrillation of the heart modeling and finite element solution is proposed in this study. In order to solve the problem that ordinary clinical trials could not measure the actual distribution of the defibrillation electric field in the heart accurately, this method provides a research tool for electrical defibrillation. A complete atrial anatomical structure in the heart model is used in the research, the finite element method is proceeded to solve; Three parameters: defibrillation threshold voltage, the high field strength rate and the defibrillation threshold energy are set to evaluate the effect of defibrillation. The heart electric field distributions of transvenous atrial defibrillation with different electrode locations or sizes are simulated. The simulation results and the reported results match fairly well, which initially verify the feasibility of this method.
Atrial Fibrillation ; therapy ; Computer Simulation ; Electric Countershock ; instrumentation ; methods ; Electrodes

OBJECTIVETo determine the feasibility and efficiency of terminating atrial flutter (AFL) and atrial fibrillation (AF) using synchronous low-energy shocks delivered through a novel transesophageal electric balloon electrode system.

METHODSBy using a novel electric balloon electrode system, we attempted 91 transesophageal cardioversions in 52 patients, to treat 53 episodes of AFL and 38 episodes of AF.

RESULTSOf the 40 patients of AFL that failed to respond to drug therapy, 37 (92.5%) were successfully countershocked to sinus rhythm by transesophageal cardioversion, with a mean energy of (22.70 +/- 4.50) J (20 - 30 J). Of the 19 patients in AF, transesophageal cardioversion was successful in 16 (84.2%) cases, requiring a mean delivered energy of (17.38 +/- 8.58) J (3 - 30 J). There were no complications such as heart block or ventricular fibrillation, and no evidence of esophageal injury.

CONCLUSIONSTransesophageal cardioversion using an electric balloon electrode system is an effective and feasible method for the treatment of AFL and AF. It requires low energy and no anesthesia, leads to less trauma, and shows a high cardioversion success rate that may prove valuable in the management of tachyarrhythmias.

Atrial Fibrillation ; therapy ; Atrial Flutter ; therapy ; Electric Countershock ; instrumentation ; methods ; Electrodes ; Esophagus ; Humans ; Treatment Outcome

OBJECTIVEImportant studies of cardiopulmonary resuscitation (CPR) techniques influence the development of new guidelines. We systematically reviewed the efficacy of some important studies of CPR.

DATA SOURCESThe data analyzed in this review are mainly from articles included in PubMed and EMBASE, published from 1964 to 2014.

STUDY SELECTIONOriginal articles and critical reviews about CPR techniques were selected for review.

RESULTSThe survival rate after out-of-hospital cardiac arrest (OHCA) is improving. This improvement is associated with the performance of uninterrupted chest compressions and simple airway management procedures during bystander CPR. Real-time feedback devices can be used to improve the quality of CPR. The recommended dose, timing, and indications for adrenaline (epinephrine) use may change. The appropriate target temperature for targeted temperature management is still unclear.

CONCLUSIONSNew studies over the past 5 years have evaluated various aspects of CPR in OHCA. Some of these studies were high-quality randomized controlled trials, which may help to improve the scientific understanding of resuscitation techniques and result in changes to CPR guidelines.

Cardiopulmonary Resuscitation ; methods ; Electric Countershock ; methods ; Epinephrine ; therapeutic use ; Humans ; Out-of-Hospital Cardiac Arrest ; prevention & control ; Temperature

The objective of this study is to evaluate the correlation between the absolute ventricular fibrillation voltage (AVFV) computed from electrocardiogram (ECG) and the outcome of defibrillation shocks. Orthogonal ECG (sagittal, x; transverse, y; and longitudinal, z) was recorded from 11 dogs during 10 seconds of electrically induced ventricular fibrillation followed by defibrillation shocks with 50% probability of success. The transvenous two-leads defibrillation system was used to deliver defibrillation shocks. The envelope voltage was estimated by using the Hilbert transform. The comparison of the envelope voltages between 236 successful trials and 249 unsuccessful trials did not show any consistent and statistically significant differences. In contrast with the previously reported correlation, the moving average of AVFV was not higher in the successful trials. In the Z direction, the successful trials had lower voltage than did the unsuccessful trials (P < 0.05). These results suggest that the absolute voltage of ECG during ventricular fibrillation is not robustly correlated with the outcome of defibrillation shocks.
Animals ; Dogs ; Electric Countershock ; Electrocardiography ; methods ; Female ; Male ; Models, Theoretical ; Signal Processing, Computer-Assisted ; Ventricular Fibrillation ; physiopathology ; therapy

Arrhythmia, Sinus ; physiopathology ; therapy ; Atrial Fibrillation ; physiopathology ; therapy ; Electric Countershock ; methods ; Humans ; Male ; Middle Aged ; Treatment Outcome

OBJECTIVETo observed the clinical efficacy of cardiac resynchronization therapy-defibrillator (CRT-D) in selected patients with chronic heart failure one year after implantation.

METHODSSeventeen patients with drug-refractory heart failure received CRT-D implantation (6 patients were implanted with InSync Sentry). The underlying heart diseases were dilated cardiomyopathy in 12 patients and ischemic heart disease in 5 patients. There were 13 patients with a history of ventricular tachycardia/ventricular fibrillation.

RESULTSCRT-D were successfully implanted in all patients without complication. The mean left ventricular pacing threshold was 1.6 V. The defibrillation threshold was no more than 20 J. During a mean follow-up of 13 months, no death occurred and LV function was improved. The shock induced by ventricular tachycardia was delivered in 5 patients and alarming due to heart failure occurred twice in 1 patient.

CONCLUSIONSThe implantation of CRT-D for treating refractory heart failure patients is feasible and safe. The application of CRT-D was associated with an improved cardiac function and a reduced risk of sudden cardiac death.

Adult ; Aged ; Aged, 80 and over ; Cardiac Pacing, Artificial ; methods ; Chronic Disease ; Defibrillators, Implantable ; Electric Countershock ; methods ; Female ; Heart Failure ; therapy ; Humans ; Male ; Middle Aged ; Pacemaker, Artificial

This study evaluates the immediate effects of the endocardial electrical defibrillation delivered by two transvenous defibrillation systems on left ventricular (LV) function in the animal model. Automatic cardiac defibrillation systems with bipolar leads (group I) and tripolar leads (group II) were placed in the hearts of 10 dogs (group I) and 10 pigs (group II),respectively. Transesophageal echocardiography with two dimensional image, M-mode and pulse Doppler were performed at baseline and after several episodes of defibrillation (DF). Each animal in group 1 underwent 4 DF with 64 Joules; the animals in group2 underwent an average of 8 DF with a total of 210 Joules. LV fractional area contraction, isovolumic relaxation time, and both ratios of velocities and time-velocity integrals in transmitral Doppler flow E and A waves exhibited no significant change after the shocks. This study suggests that the repeated low-energy electrical countershocks delivered by two transvenous defibrillation systems do ndt cause LV global systolic and/or diastolic dysfunction.
Animals ; Dogs ; Echocardiography, Transesophageal ; Electric Countershock ; instrumentation ; methods ; Female ; Male ; Swine ; Therapy, Computer-Assisted ; methods ; Ventricular Fibrillation ; physiopathology ; therapy ; Ventricular Function, Left ; physiology

OBJECTIVE: Direct current cardioversion for atrial fibrillation could be associated with the risk of thromboembolic events. Anticoagulation therapy with warfarin (INR 2.0-3.0) is recommended 3 weeks before and 4 weeks after cardioversion to reduce the risk of thromboembolism. This study evaluated warfarin therapy in pharmacist-managed anticoagulant services (ACS). METHODS: This retrospective study was performed in 106 patients with atrial fibrillation from 2012 to 2013. The primary efficacy endpoint was the composite of stroke, transient ischemic attack, myocardial infarction, and cardiovascular death. The primary safety measure was major bleeding. To evaluate the peri-procedural effects of warfarin treatment, we studied whether target INR was maintained, as well as the maintenance period of the therapeutic range. Quality of treatment was measured by time in therapeutic range (TTR) by using the Rosendaal method. RESULTS: There were no thromboembolic events, but TEE examination at time of cardioversion showed a left atrial thrombus in three patients (2.8%). Bleeding complications after cardioversion occurred in 2 patients (1.9%). The average INR value at the time of cardioversion was 2.59±0.8, and was within the therapeutic range in 83 patients (78%). Analysis of the patients in whom the value was within the therapeutic range twice consecutively showed that the ratio of TTR was 80% and the therapeutic range was maintained in 67 patients (63%) for an average of 4.90 weeks prior to cardioversion. Similarly, 76 patients (72%) had a stable INR within the therapeutic range for an average of 5.70 weeks and a mean TTR of 83%. CONCLUSION: Pharmacists significantly contributed to appropriate warfarin treatment with close monitoring during cardioversion. Likewise, active pharmacist monitoring and systemic management should be considered to reduce thromboembolism and bleeding complications in the peri-cardioversion period.
Atrial Fibrillation* ; Electric Countershock* ; Hemorrhage ; Humans ; International Normalized Ratio ; Ischemic Attack, Transient ; Methods ; Myocardial Infarction ; Pharmacists ; Retrospective Studies ; Stroke ; Thromboembolism ; Thrombosis ; Warfarin*

PURPOSE: The clinical significance of post-procedural atrial premature beats immediately after catheter ablation for atrial fibrillation (AF) has not been clearly determined. We hypothesized that the provocation of immediate recurrence of atrial premature beats (IRAPB) and additional ablation improves the clinical outcome of AF ablation. MATERIALS AND METHODS: We enrolled 200 patients with AF (76.5% males; 57.4+/-11.1 years old; 64.3% paroxysmal AF) who underwent catheter ablation. Post-procedure IRAPB was defined as frequent atrial premature beats (> or =6/min) under isoproterenol infusion (5 microg/min), monitored for 10 min after internal cardioversion, and we ablated mappable IRAPBs. Post-procedural IRAPB provocations were conducted in 100 patients. We compared the patients who showed IRAPB with those who did not. We also compared the IRAPB provocation group with 100 age-, sex-, and AF-type-matched patients who completed ablation without provocation (No-Test group). RESULTS: 1) Among the post-procedural IRAPB provocation group, 33% showed IRAPB and required additional ablation with a longer procedure time (p=0.001) than those without IRAPB, without increasing the complication rate. 2) During 18.0+/-6.6 months of follow-up, the patients who showed IRAPB had a worse clinical recurrence rate than those who did not (27.3% vs. 9.0%; p=0.016), in spite of additional IRAPB ablation. 3) However, the clinical recurrence rate was significantly lower in the IRAPB provocation group (15.0%) than in the No-Test group (28.0%; p=0.025) without lengthening of the procedure time or raising complication rate. CONCLUSION: The presence of post-procedural IRAPB was associated with a higher recurrence rate after AF ablation. However, IRAPB provocation and additional ablation might facilitate a better clinical outcome. A further prospective randomized study is warranted.
Atrial Fibrillation/*physiopathology ; *Cardiac Complexes, Premature ; Catheter Ablation/*methods ; *Electric Countershock ; Female ; Humans ; Male ; Middle Aged ; Prospective Studies ; *Recurrence ; Treatment Outcome

BACKGROUND: Lone atrial fibrillation(LAF) is defined by the presence of atrial fibrillation(AF) in the absence of any other clinical evidence to suggest a primary cardiac disease. In general, it has been accepted that LAF is a benign from of AF, but there is some evidence that LAF may induce atrial enlargement and left ventricular dysfunction. Atrial enlargement has also been reported to reduce the success rate of cardioversion to sinus rhythm, and in addition thrombus formation is more likely to occur in larger atria. Therefore this study was designed to detect any structural characteristics or functional abnormality in patients with LAF. METHOD: Twenty six patients with LAF(19 men and 7 women ; age 52±12 years) were studied by echocardiography and compared with 12 normal persons(2 men and 10 women ; age 47±7 years). Patients were divided into recurrent paroxysmal group(11 patients) and chronic group(15 patients) according to the character of LAF. Three orthogonal dimensions of both left atrium(LA) and right atrium(RA) were measured echocardiographically, and atrial volume was calculated. Peak early diastolic transmitral inflow velocity(E), peak velocity during atrial contraction(A), and deceleration time(DT) of E wave measured by Doppler echocardiography. RESULTS: Cardiac abnormalities in patients include trivial mitral regurgitation(12 cases), trivial tricuspid regurgitation(8 cases), senile aortic valve sclerosis(7 cases), and mild senile calcification of mitral annulus(1 case) and papillary moscle(1 case). LA volume(65.1±32.8 vs 38.3±10.4cm2, p < 0.01), RA volume(65.6±23.0 vs 38.7± 10.3cm2, p < 0.01), and DT(216±32 vs 194±19msec, p < 0.05) were significantly increased in patients with LAF as compared with the cotrol group. RA volume(54.2±16.6 vs 38.7±10.3cm2, p < 0.05) and DT(231±23 vs 194±19msec) were significantly increased, and E/A(1.1±0.4 vs 1.4±0.3 p < 0.05) was signficantly decreased in the parxysmal group as compared with the control group. LA volume(78.4±33.9 vs 46.9±21.3cm2, p < 0.01) and RA volume(74.0±23.9 vs 54.2±16.6cm2, p < 0.05) were significantly increased and left ventricular ejection fraction(60±7 vs 68±6%, p < 0.01) tended to be decreased in the chronic group as compared with the paroxysmal group. CONCLUSION: Atrial enlargement and left ventricular diastolic dysfunction were noted in patients with LAF. The degree of atrial enlargement in the chronic group was much more than that in the paroxysmal group. We conclude that LAF per se is associated with both atrial enlargement. Left ventricular diastolic dysfunction in these patients needs to be further investigated.
Aortic Valve ; Atrial Fibrillation ; Deceleration ; Echocardiography ; Echocardiography, Doppler ; Electric Countershock ; Female ; Heart Diseases ; Humans ; Male ; Methods ; Thrombosis ; Ventricular Dysfunction, Left ; Ventricular Function, Left