A Brief Review of a Common Clinical Question: Intravenous Diltiazem or Metoprolol for Atrial Fibrillation with Rapid Ventricular Response?

Two classes of rate controlling medications—beta blockers (BBs) and non- dihydropyridine calcium channel blockers (CCBs)—are given to patients who present with atrial fibrillation (AF) with rapid ventricular response (RVR). Both are Class I recommendations from the American Heart Association (AHA), American College of Cardiology (ACC), and Heart Rhythm Society (HRS) for the management of AF with RVR. Multiple studies support the view that diltiazem is more effective than metoprolol, even though data from the AFFIRM trial suggests BBs are more frequently used. CCBs are generally avoided in AF with RVR patients who have concomitant heart failure with reduced ejection fraction (HFrEF) for concern of triggering decompensation. However, some recent studies indicate this idea may be unfounded. The aim of this article is to compare the efficacy of diltiazem and metoprolol for rate control in AF with RVR and examine the use of diltiazem in patients with both AF with RVR and HFrEF.

Application of Positron Emission Tomography in the Detection of Myocardial Metabolism in Pig Ventricular Fibrillation and Asphyxiation Cardiac Arrest Models after Resuscitation

Objective To study the application of positron emission tomography （PET） in detection of myocardia metabolism in pig ventricular fibrillation and asphyxiation cardiac arrest models after resuscitation. Methods Thirty-two healthy miniature pigs were randomized into a ventricular fibrillation cardiac arrest （VFCA） group （n=16） and an asphyxiation cardiac arrest （ACA） group （n=16）. Cardiac arrest （CA） was induced by programmed electric stimulation or endotracheal tube clamping followed by cardiopulmonary resuscitation （CPR） and defibrillation. At four hours and 24 h after spontaneous circulation was achieved, myocardial metabolism was assessed by PET. 18F-FDG myocardial uptake in PET was analyzed and the maximum standardized uptake value （SUVmax） was measured. Results Spontaneous circulation was 200% and 62.5% in VFCA group and ACA group, respectively. PET demonstrated that the myocardial metabolism injuries was more severe and widespread after ACA than after VFCA. The SUVrnax was higher in VFCA group than in ACA group （P〈0.01）. In VFCA group, SUVmax at 24 h after spontaneous circulation increased to the level of baseline. Conclusion ACA causes more severe cardiac metabol associated with less successful resuscitation. Myocardial sm injuries than VFCA. Myocardial dysfunction is stunning does occur with VFCA but not with ACA.

A case of applying left bundle branch pacing combined with atrioventricular node ablation to treat atrial fibrillation-induced heart failure

The core treatment of rapid arrhythmiainduced heart failure(HF)is to control the ventricular rate to an optimized lower level,which is usually achieved with various anti-arrhythmic drugs.However,arrhythmias may not respond well to pharmaceutical treatment for various reasons.Iatrogenic atrioventricular(AV)node ablation needs to be performed under these extreme conditions to lower the patient’s heart rate.

Trigger elimination of polymorphic ventricular tachycardia and ventricular fibrillation by catheter ablation:trigger and substrate modification

Ventricular fibrillation （VF） is a malignant arrhythmia, usually initiated by a ventricular premature contraction （VPC） during the vulnerable period of cardiac repolarization. Ablation therapy for VF has been described and increasingly reported. Targets for VF triggers are VPCs preceded by Purkinje potentials or from the right ventricular outflow tract （RVOT） in structurally normal hearts, and VPC triggers preceded by Purkinje potentials in ischemic cardiomyopathy. During the session, mapping should be focused on the earliest activation and determining the earliest potential is the key to a successful ablation. However, suppression of VF can be achieved by not only the elimination of triggering VPCs, but also by substrate modification of possible reentry circuits in the Purkinje network, or between the PA and RVOT. The most important issue before the ablation session is the recording of the 12-lead ECG of the triggering event, which can prove invaluable in regionalizing the origin of the triggering VPC for more detailed mapping. In cases where the VPC is not spontaneous or inducible, ablation may be performed by pace mapping. Further studies are needed to evaluate the precise mechanisms of this arrhythmia.

Idiopathic ventricular fibrillation with fragmented QRS complex and J wave in resting electrocardiogram

ObjectiveTo 在放松从 21 大小写的考察数据在我们的医院里使遭到的 electrocardiogram.MethodsWe 与碎裂的 QRS 建筑群( f-QRS )和 J 波浪描述自发的室的纤维性颤动( IVF )的临床的特征由于 IVF 在心脏的拘捕以后被复活并且在放松心电图估计了 f-QRS 和 J 波浪的流行( ECG )。所有盒子题目基于 electrocardiographic 形态学在三个组之中被分类：组我， f-QRS 和 J 波浪被观察(n = 6 ) ，组 II，仅仅 J 波浪被观察(n = 9 ) ，组 III，两 f-QRS 也不 J 波浪被观察(n = 6 ) 。人口特征，中略的历史或突然的心脏的拘捕，室的纤维性颤动( VF )的发生，和 VF 的情形在索引事件的三 groups.ResultsThe 发生之中被评估(中略，在可植入的 cardioverter 使用高压脉冲来消减心脏( ICD )或心律调整器记录的熬过的心脏的拘捕和 VF 事件)是 13.4 &#x000b1 ；在组的 5.6 每年我， 10.8 &#x000b1；在组 II 的 3.9 每年，和 9.8 &#x000b1；在组 III 的 4.2 每年。在在三个组，之中的发生有重要差别最经常的索引事件在组被观察我。为发生的危险比率是 3.2 (95%CI， 1.1-7.9；P = 0.01 ) 。索引事件的历史和情形在这些组之中是不同的。在组我，所有索引事件在清早发生在睡觉期间。在组 II，四个题目在奋发的物理活动或焦虑状态期间承受了 VF，二在在清早的睡觉期间，三在里面平常的活动。在组 III ，一个题目在清早在睡觉期间承受了 VF ，处于焦虑状态的，四在平常的 activity.ConclusionsThis ，学习建议有在休息 ECG 的 f-QRS 和 J 波浪的联合外观的 IVF 病人承受 VF 的增加的风险， IVF 病人的这亚群有一个唯一的临床的特征。

Detection of Ventricular Fibrillation Using Random Forest Classifier

Early warning and detection of ventricular fibrillation is crucial to the successful treatment of this life-threatening condition. In this paper, a ventricular fibrillation classification algorithm using a machine learning method, random forest, is proposed. A total of 17 previously defined ECG feature metrics were extracted from fixed length segments of the echocardiogram (ECG). Three annotated public domain ECG databases (Creighton University Ventricular Tachycardia database, MIT-BIH Arrhythmia Database and MIT-BIH Malignant Ventricular Arrhythmia Database) were used for evaluation of the proposed method. Window sizes 3 s, 5 s and 8 s for overlapping and non-overlapping segmentation methodologies were tested. An accuracy (Acc) of 97.17%, sensitivity (Se) of 95.17% and specificity (Sp) of 97.32% were obtained with 8 s window size for overlapping segments. The results were benchmarked against recent reported results and were found to outper-form them with lower complexity.

Epidemiology and genetics of ventricular fibrillation during acute myocardial infarction

从室的纤维性颤动(VF ) 的突然的心脏的死亡(SCD ) 在冠的动脉疾病(CAD ) 期间是全部、心血管的死亡的一个领先的原因，并且在里面多于 SCD 盒子的一半， VF 作为 CAD 的第一症状发生。几流行病学的研究证明了一个家庭成员的突然的死亡在尖锐心肌的梗塞(MI ) 期间是为 SCD 和 VF 的一个风险因素，独立于包括 MI 的家庭历史的传统的风险因素，在危险性建议一个基因部件到 VF。由于 MI 阻止 SCD 和 VF，我们需要在这张显然健康的人口引起 VF 的基因、分子的机制的更好的理解。尽管新卓见和技术变得可得到，到 VF 的基因倾向在 MI 期间仍然保持糟糕理解。，从许多不同基因研究的调查结果没能到达重制度几基因变体，普通、稀罕的变体，被联系了到 VF 或 SCD。为这评论，我们在 PubMed 找了潜在地相关的文章，用下列网孔术语：突然的心脏的死亡，室的纤维性颤动， out-of-hospital 心脏的拘捕，心肌的梗塞，心肌的局部缺血，冠的动脉疾病，和遗传。这评论由于 MI 为基因危险性描述传染病学和证据到 VF。

An Experimental Comparative Study on the Characteristicsof Ventricular Fibrillation during Cardiac Arrest and Methoxamine Administration

The effect of a pure α-adrenergic agent, methoxamine on ventricularfibrillation (VF) amplitude and the relation between hemodynamic parameters andsurvival in a rodent cardiopulmonary resuscitation (CPR) model were studied.Our results suggested that: 1) VF amplitude decreased during untreated VF, butit increased during pericardial chest compression ; 2) methoxamine significantly increased the mean aortic pressure (MAP) and coronary perfusion pressure (CPP)but not VF amplitude, and the survival also increased due to elevation of CPP;and 3) all surviving animals with successful defibrillhtion had a higher VF ampli-tude.

Permanent Pacemaker Implantation in a Patient with Ventricular Fibrillation due to Spontaneous Coronary Artery Dissection: A Case Report

We present here the case of a 43-year-old female without any known past medical history who was brought into the emergency department (ED) by the emergency medical services (EMS) after receiving cardiopulmonary resuscitation (CPR) on the field. Per EMS, on arrival patient was found to be on ventricular fibrillation and was shocked 3 times. Patient had no past medical history. In the ED, EKG showed sinus rhythm and troponin was 23 which is slightly high compared to upper limit. Patient was taken to the cath lab immediately which showed small to medium caliber septal 1 branch severe mid segment disease with distal tapering suggestive of spontaneous coronary artery dissection. No stent was placed. Electrophysiology was consulted and an Implantable Cardioverter Defibrillator was placed. Spontaneous coronary artery dissection (SCAD) is a phenomenon where an epicardial coronary artery dissection occurs that is not related to atherosclerosis, trauma or iatrogenia. Patients with SCAD presenting with ventricular arrhythmias are not very common. In a Canadian registry analyzing 1056 patients with SCAD, only 84 of them presented with ventricular fibrillation (VF) or ventricular tachycardia (VT) and only 8 underwent ICD placement. They followed up the patients for 5 years and 8 patients suffered VT/VF. 5 of those 8 patients had VT/VF on initial SCAD presentation, and only 1 of them had undergone ICD insertion. There are no specific guidelines regarding ICD placement on patients with coronary artery dissection, but the AHA/ACC/HRS guidelines can help us make decisions. Our case underscores the importance of more prospective or retrospective studies to identify those patients with SCAD who would benefit from ICD placement for secondary prevention. The current guidelines for ventricular arrhythmias are an excellent tool for the electrophysiologist regarding the management of these arrhythmias in other specific scenarios but guidance on SCAD is still lacking.

Does Minimizing Ventricular Pacing Reduce the Incidence of Atrial Fibrillation ? A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background:Right ventricular pacing disrupts atrioventricular synchrony and increases the risk of atrial fi brillation(AF).However,whether algorithms for minimizing ventricular pacing reduce the incidence of AF remains controversial.Therefore,we conducted a systematic review and meta-analysis to compare the incidence of AF between minimizing ventricular pacing and conventional pacing protocols in patients with pacemakers implanted.Methods:The PubMed,Embase,and Cochrane Library databases were searched up to August 1,2017,for randomized controlled trials that reported the incidence of AF in patients with and without the use of algorithms for minimizing ventricular pacing.Results:Eleven studies comprising 5705 participants(61%males,mean age 71 years[standard deviation 11 years])were fi nally included in the analysis.The mean follow-up duration was 24 months.Use of algorithms for minimizing ventricular pacing signifi cantly reduced the incidence of AF,with an odds ratio of 0.74(95%confi dence interval 0.55–1.00;P<0.05).There was moderate heterogeneity among studies(I 2=63%).Conclusions:The incidence of AF was reduced by 26%with use of algorithms for minimizing ventricular pacing.The incorporation of such algorithms in routine clinical practice should in theory lead to a decrease in AF-related morbidity and mortality.

Ventricular fibrillation and sudden cardiac arrest in apical hypertrophic cardiomyopathy:Two case reports

BACKGROUND Apical hypertrophic cardiomyopathy(HCM)is considered to have a benign prognosis in terms of cardiovascular mortality.This serial case report aimed to raise awareness of ventricular fibrillation(VF)and sudden cardiac death(SCD)in apical HCM.CASE SUMMARY Here we describe two rare cases of apical HCM that presented with documented VF and sudden cardiac collapse.These patients were previously not recommended for primary prevention using implantable cardioverter-defibrillator(ICD)therapy based on current guidelines.However,both received ICD therapy for the secondary prevention of SCD.CONCLUSION These cases illustrate serious complications including VF and aborted sudden cardiac arrest in apical HCM patients who are initially not candidates for primary prevention using ICD implantation based on current guidelines.

Ventricular Fibrillation Caused by Traumatic Coronary Artery Dissection

Coronary artery dissection due to blunt chest trauma (traumatic coronary artery dissection [TCAD]) may heal spontaneously, and some surgeons believe that conservative or elective treat-ments are sufficient, provided that there are no progressing ischemic symptoms. However, we report a patient who experienced sudden ventricular fibrillation (VF) during initial medical care for trauma injuries. The 32-year-old woman was riding in a passenger car when an accident occurred, and was subsequently transported to our emergency department. Twelve-lead electrocardiography revealed ST segment elevation in leads II, III, and aVF, although her vital signs remained stable. Therefore, we prioritized assessing the trauma at other sites, and VF suddenly occurred. Coronary angiography was performed with repeated defibrillation and chest compressions, which resulted in recovery of spontaneous circulation. Occlusion was observed in the right coronary artery, which we treated with balloon angioplasty. However, intravascular ultrasonography (IVUS) subsequently revealed coronary artery dissection, a stent was placed, and the patient successfully recovered. Therefore, IVUS may be useful for diagnosing TCAD, and swift intervention is needed if TCAD is detected.

Factors influencing survival of patient with in-hospital ventricular fibrillation： experience of a single center

评估影响承受了在里面医院的病人的结果的因素的目的室的纤维性颤动(IHVF ) 。有在一个单个中心的 IHVF 的病人的方法数据是镇定的。病人的临床的特征在熬过的那些(n=112 ) 之间被比较，那些死了(n=94 ) ，并且那些与 IHVF 发生在住院病人病房并且在紧急情况中心。多重逻辑回归分析被用来识别与幸存联系的因素。在那里的结果是在分析的 206 个事件。最普通的位于冠的动脉疾病(CAD ) 下面疾病是，特别尖锐的心肌的梗塞(AMI ) 。在多重逻辑回归分析上，为失败的独立预言者幸存是更高的 NYHA 班(机会比率1.7,95% CI ， 13-2.2 ， P < 0.001 )，更低的浆液钾集中([K+])(机会比率，2.9,95% CI ， 1.9-4.3 ， P=0.007 )并且肾上腺素用法(机会比率，25,95% CI 11.5-55.1 ， P < 0.001 )。紧急情况组有更好的 NYHA 班(P = 0.012 ) ，更低[K+](P < 0.001 ) 比在里面住院病人病房组。Hypokalemia (浆液钾水平 < 4.5 mmol/L ) 在紧急情况组与 AMI 在所有病人被发现。在 AMI 亚群， 56.9% IHVF 事件在 AMI 以后发生在第一天以内，并且在 2 个星期以内减少。有梗塞经常联系了动脉(IRA ) 的恰好冠的动脉(8/9,88.9%) 的病人有 bradycardia (R-R 间隔 > 1s ) 在 IHVF 的出现前，当那些经常作为 IRA 与左前面的下降动脉显示出心悸亢进时(R-R 间隔 < 0.6s )(8/12,66.7%) 。引起 IHVF 的最普通的疾病是 CAD 的结论。保留[K+] 上面的 4.5mmol/l 能阻止 on-setting IHVF，特别到 AMI 病人。更坏的心功能与 IHVF 和更坏的预后的更高的率被联系。

Effects of Bisoprolol on the ventricular function and hemodynamics in patients with atrial fibrillation and chronic heart failure

Background: Recent data suggest that beta-blockers can be beneficial in patients with chronic heart failure (CHF). Atrial fibrillation (AF) is present in a significant number of patients with CItF and is associateing with significant morbidity and increasing mortality rates.Thus it is necessary to establish therapy to improve the poor prognosis in this highrisk population, but a specific benefit of beta-blockers to the subset with concomitant AF and CHF has been little demonstrated. Objective: To examine the effects of Bisoprolol (6 months treatment) on the ventricular function and hemodynamics in patients with AF and CHF. Methods: 84 patients with stable CHF(NYHA≤Ⅲ class)and AF were assigned to TreatedGroup(n=37) or Control group Ⅰ (n=22, 24-hour heart mean rate<70/min) or Control Group Ⅱ (n=25, 24-hour heart mean rate≥70/min). All patients were given the basic therapy for CHF, and Treated Group received Bisopolol. Clinical and echocardiographic variables were measured in 3 groups at baseline and after 6 months, and the results were compared. Results: After 6 months of treatment with Bisoprolol, left ventricular ejection fraction (LVEF) and NYHA class had significantly improved (P<0.05), and a trend towards a reduction in combined end point of death or CHF hospitalization was also observed (P<0.20) in Treated Group; The increase of LVEF in Treated Group were associated with a reduction in mitral regurgitation degree and left atrial volume; The heart rate in mean 24-hour and at peak exercise decreased in Treated Group, but were similar to that in Control Group Ⅰ . Conclusion: 6 months of Bisoprolol therapy resulted in an improvementin the NYHA class and LVEF, and also showed a trend towards a reduction in hospitalization or death. The beneficial effects of Bisoprolol on patients with AF and CHF may be partly mediated by improvement of ventricular diastolic function.

The Relation Between Hypertrophied Myocardium and Ventricular Fibrillation Threshold in Spontaneously Hypertensive Rats

Objectives To investigate the relation between hypertrophied myocardium and ventricular fibrillation threshold in spontaneously hypertensive rats （SHR）. Methods 20 male SHR were randomly divided into two groups： 10 week group （n= 10） and 18 week group （n=10）. 10 week male Wistar rats were controlled group （n=10）. The systolic blood pressure （SBP）, heart mass index （HMI）, ventricular effective refractory period （VERP） and ventricular fibrillation threshold（VFT） were measured respectively.① The SBP and HMI of SHR were significantly higher than those of Wistar rats（P 〈 0.001）. The VFT of SHR were significantly lower than that of Wistar rats （P 〈 0.001）.②In SHR, the SBP and HMI of 18 week SHR were significantly higher than those of 10 week SHR （P 〈 0.001）. The VFT of 18 week SHR were significantly lower than that of 10 week SHR （P 〈 0.001）. ③There were no significant difference of VERP among 10 week SHR, 18 week SHR and Wistar rats（P 〉 0.05）. ④There was no relationship between HMI and VFT or SBP in Wistar rats. There was significant relationship between HMI and VFT or SBP in different age spontaneously hypertensive rats. ⑤HMI, age and species of animal were the major influent factors of VFT. Conclusions The VFT of hypertrophied myocardium decreased. The higher the degree of hypertrophy of myocardium and the higher the systolic blood pressure were, the lower the ventricular fibrillation threshold was.

Comparison Between Diltiazem and Cedilanid-D on Ventricular Rate Control of Atrial Fibrillation and Their Effect on Atrioventricular Conduction System.

Objectives This randomized study was designed to compare the safety and efficacy of intravenous diltiazem versus intravenous cedilanid-D （deslanoside） for ventricular rate control in patients with atrial fibrillation （AF）. Analysis of the effect on conduction system of these drugs was also performed. Methods Forty three patients with AF were randomly assigned to receive intravenous therapy with 0.25mg/kg diltiazem （n = 21） or 0.4rag cedilanid-D （n = 22）. If not effective at 120 minutes （〈 20% decrease in pretreatment ventricular rate or can not convert to sinus rhythm= another dose of diltiazem or 0.2mg cedilanid-D was administered. Blood pressure and electrocardiographic recordings were performed before and after 5, 10, 20, 30, 60 minutes of drug administration. Further recordings were performed at 120 minutes in noneffective patients, and at 180 minutes in patients who received second time drug administration. To evaluate the effect on conduction system of these two drugs by measuring PA, AH and HV intervals using His bundle electrogram test another nineteen sinus rhythm patients were randomized to dihiazem （n=9） and cedilanid （n= 10） group. His bundle electrogram recordings were performed before and after 5, 10, 20 and 30 minutes of drug administration. Statistical significance was assessed with the use of t test, Fisher＇s exact test, ANOVA and LSD methodology. Results At baseline and after 5, 10, 20, 30, 60 minutes of drug administration the heart rates （mean±SD） were（133±15）, （92±20）, （87±22）, （85 ±20）, （85±21）, （85 ±23）beats/minute in diltiazem group respectively and（ 140±21 ）, （ 122±24）, （118±25）, （110±26）, （112±25）, （110±28） beats/ minute in cedilanid-D group respectively. Heart rate reduction was higher in diltiazem group than cedilanid group during 5 （41±20 vs 17±14,P 〈 0.01）; 10 （46±21 vs 22±20, P〈0.01）; 20 （48±21 vs 29±22, P〈0.01 ） ; 30（48±22 vs 27±22,P〈0.01 ）and 60 minutes （48±23 vs 29±24, P〈 0.05）. Both drugs had no effect on both systolic and diastolic blood pressure （P 〉0.05） and no major side effects were noticed. Diltiazem maintained effective ventrieular rate in 20 patients, whereas eedilanid-D maintained in 15 patients within 180 minutes （95.2%vs 68.2%,P〈 0.05）. There were no statistical significance in baseline heart rate, age and weight between the two groups. Both diltiazem and cedilanid-D can increase AH interval, but have no effect on HV and PA intervals in sinus rhythm patients. Conclusions Both dihiazem and eedilanid-D decrease ventrieular heart rate, but heart rate reduction is significantly higher in diltiazem group, thus should be considered as a drug of choice for emergency control of ventrieular rate. Under clinical monitoring this dose of diltiazem seems to be safe and applicable in AF patients with congestive heart failure. Both drugs have no effect on PA and HV intervals but increase the AH interval thereby can reduce ventricular rate.

Resuscitation from Prolonged Ventricular Fibrillation by Epinephrine Combined with Sodium-Hydrogen Exchanger Isoform-1 Inhibitor Cariporide

Objective To test the resuscitative effects from prolonged ventricular fibrillation by epinephrine combined with sodium hydrogen exchanger isoform 1 inhibitor Cariporide. Methods 16 rats were received a 3 mg/kg bolus of Cariporide or the same volume of 0.9%NaCl solution (control) 15 seconds before completion 12 minutes untreated VF. Chest compression (CC) was started for a total of 8 minutes. Adjusted the depth of compressor so that the aortic diastolic pressure to 25～28 mmHg during the 2nd minute of CC. Fix the depth of the piston and this depth was used throughout the remaining 6 minutes of CC. 10 seconds before starting the 3rd minute of chest compression, injected epinephrine (30 μg/kg). Recorded the time at which restoration of spontaneous circulation (ROSC) occurred in Cariporide treated rats. Electrical defibrillation was timed in control group to match the time of spontaneous defibrillation in Cariporide treated rats. To the rats, which cant be defibrillated spontaneously, received chest compression and rescues electrical shocks. Results compared with control group, with the same CC depth, Cariporide treated rats received the higher and longer lasting coronary perfusion pressure (P< 0.05), higher resuscitative rate (P< 0.05), less post resuscitative ventricular ectopic activities (P< 0.001), better hemodynamic effects and longer survival time (P< 0.05). Conclusion Epinephrine combined with sodium hydrogen exchanger isoform 1 inhibitor Cariporide may represent a novel and remarkably effective intervention for resuscitation from prolonged VF.

Comparison of Plegisol and Modified ST Thomas Hospital Cardioplegic Solution in the Development of Ventricular Fibrillation after Declamping of the Aorta

Ventricular fibrillation seen just after declamping of the aorta is an undesirable condition causing myocardial injury. To return to normal rhythm, often internal shocks are applied. But defibrillation itself can also contribute to myocardial injury. So prevention of fibrillation is more important than treatment. 236 patients undergoing coronary artery by-pass surgery were included in this retrospective clinical study. 144 of those patients were operated using modified St. Thomas’ Hospital cardioplegic solution, for stopping the heart. In the other 92 patients, plegisol cardioplegic solution was used. We compared the two groups for the development of ventricular fibrilation after declamping of the aorta. In the modified St. Thomas’ Hospital group, ventricular fibrillation after declamping of the aorta was seen less frequently, this being statistically significant (22.2% vs. 52.2%, p = 0.026). This study shows that the modified St.Thomas’ Hospital cardioplegic solution is preferred for avoiding ventricular fibrillation occuring just after declamping of the aorta.

Analysis of Incidence of Atrial Fibrillation after Implantation of VVI Pacemaker-Long-term Observation of 154 Patients

Incidence of occurrence of atrial fibrillation (Af) after implantation of VVI was examined and the possible mechanism was explored. Eighty cases of atriouentricular block (AVB) and 74 cases of sick sinus syhdrome (SSS) were studied and followed up for 1-14 years after implantation of VVI. The endpoint was the occurrence of permanent Af. The results showed that the incidence of Af among the 154 patients was 14.3 % (22/154). And the incidence was 2. 5 % among patients with AVB (2/80), and 27 % among patients with SSS (20/74). Significant significance was found between patients with AVB and those with SSS (P<0. 01). Among the patients with SSS, the incidence was 33. 3 % (9/27) in type I, 38.1 % (8/21) in type Ⅲ and 11. 5 % (3/26) in type Ⅱ. Significant differences were revealed among patients with Ⅱ, Ⅲ and Ⅱ type SSS (P<0. 05). It is concluded that retrograde conduction of pure ventricular pacing may play the chief role of occurrence of Af.

Energy Level and Success of Internal Defibrillation for Shockable Rhythm during Cardiopulmonary Bypass in Cardiac Surgery:A Retrospective Study

Internal defibrillation is commonly indicated for shockable rhythm following cross-clamp removal in cardiac surgery.Low energy decreases the success rate of defibrillation but high energy can cause myocardial damage.This study aimed to determine the success rate of internal defibrillation for shockable arrhythmias after cardiac surgery.Retrospective data of 1,424 patients who developed shockable rhythms(ventricular fibrillation or ventricular tachycardia),and required internal defibrillation after aortic cross-clamp removal during cardiac surgery,without deep hypothermic circulatory arrest technique,from August 2015 to July 2017,were reviewed.The overall success rate of internal defibrillation in the first attempt of defibrillation was 61.5%.The success rate of the energy levels at 30,10,and 7 Jules were 66.7,64.9,and 61.5%,respectively.The success rate was higher in patients who had a better ejection fraction than those who failed after defibrillation.This was significantly associated with higher pH,higher bicarbonate,lower serum calcium,and lower total cardioplegic volume during cardiopulmonary bypass(CPB).Redo-valve surgery,valvular surgery,and combined coronary artery bypass graft with valvular surgery had a non-significantly lower success rate(p-value=0.989).Incidence of failure for defibrillate patients in redo-valvular surgery,combined coronary artery bypass graft with valve surgery,adult congenital heart defect,and valvular surgery;requiring four or five shocks was non-significantly increased.Recurrent rate of ventricular fibrillation/ventricular tachycardia was 13.5%.The success rate of internal defibrillation was not related to the dose of energy used after being weaned off CPB.