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.

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.

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.

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.

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.

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.

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.

Suxiao Jiuxin Pills Prevent Ventricular Fibrillation from Inhibiting L-type Calcium Currents CaV1.2 in vivo and in vitro

Objective: To investigate whether Suxiao Jiuxin Pills(SJP), a Chinese herbal remedy, is an anti-ventricular fibrillation(VF) agent. Methods: VF was induced by isoproterenolol(ISO) intraperitoneal injection followed by electrical pacing in mice and rabbits. The effects of SJP on the L-type calcium channel current(CaV1.2), voltage-dependent sodium channel current(INa), rapid and slow delayed rectifier potassium channel current(IKr and IKs, respectively) were studied by whole-cell patch-clamp method. Computer simulation was implemented to incorporate the experimental data of SJP effects on the CaV1.2 current into the action potential(AP) and pseudo-electrocardiography(pseudo-ECG) models. Results: SJP prevented VF induction and reduced VF durations significantly in mice and rabbits. Patch-clamp experiments revealed that SJP decreased the peak amplitude of the CaV1.2 current with a half maximal concentration(IC50) value of 16.9 mg/L(SJP-30 mg/L, –32.8±6.1 pA;Verapamil, –16.2±1.8 pA;vs. control, –234.5±16.7 pA, P<0.01, respectively).The steady-state activation curve, inactivation curve, and the recovery from inactivation of the CaV1.2 current were not shifted significantly. Specifically, SJP did not altered INa, IKr, and IKs currents significantly(SJP vs.control, P>0.05). Computer simulation showed that SJP-reduced CaV1.2 current shortened the AP duration,transiting VF into sinus rhythm in pseudo-ECG. Conclusion: SJP reduced VF via inhibiting the CaV1.2 current with in vivo, in vitro, and in silico studies, which provide experimental basis for SJP anti-VF clinical application.

Comparison of Cerebral Metabolism between Pig Ventricular Fibrillation and Asphyxial Cardiac Arrest Models

Background：Morbidity and mortality after resuscitation largely depend on the recovery of brain function.Ventricular fibrillation cardiac arrest （VFCA） and asphyxial cardiac arrest （ACA） are the two most prevalent causes of sudden cardiac death.Up to now,most studies have focused on VFCA.However,results from the two models have been largely variable.So,it is necessary to characterize the features of postresuscitation cerebral metabolism of both models.Methods：Forty-four Wuzhishan miniature inbred pigs were randomly divided into three groups：18 for VFCA group,ACA group,respectively,and other 8 for sham-operated group （SHAM）.VFCA was induced by programmed electric stimulation,andACA was induced by endotracheal tube clamping.After 8 min without treatment,standard cardiopulmonary resuscitation （CPR） was initiated.Following neurological deficit scores （NDS） were evaluated at 24 h after achievement of spontaneous circulation,cerebral metabolism showed as the maximum standardized uptake value （SUVmax） was measured by 18F-fluorodeoxyglucose positron emission tomography/computed tomography.Levels of serum markers of brain injury,neuron specific enolase （NSE）,and S100β were quantified with an enzyme-linked immunosorbent assay.Results：Compared with VFCA group,fewer ACA animals achieved restoration of spontaneous circulation （61.1% vs.94.4%,P 〈 0.01） and survived 24-h after resuscitation （38.9% vs.77.8%,P 〈 0.01） with worse neurological outcome （NDS：244.3 ± 15.3 vs.168.8 ± 9.71,P 〈 0.01）.The CPR duration of ACA group was longer than that of VFCA group （8.1 ± 1.2 min vs.4.5 ± 1.1 min,P 〈 0.01）.Cerebral energy metabolism showed as SUVmax in ACA was lower than in VFCA （P 〈 0.05 or P 〈 0.01）.Higher serum biomarkers of brain damage （NSE,S100β） were found inACA than VFCA after resuscitation （P 〈 0.01）.Conclusions：Compared with VFCA,ACA causes more severe cerebral metabolism injuries with less successful resuscitation and worse neurological outcome.

Tumor necrosis factor-α： a new mechanism of ischemic ventricular fibrillation？

Ventricular fibrillation （VF） in myocardial ischemia is called ＂ischemic VF＂. As a severe morbid state and a leading cause of sudden cardiac attack, ischemic VF induces approximately 3 million deaths in the United States each year. Ischemic VF is caused by ＂triggers＂ such as ventricular premature beat or ventricular tachycardia in the presence of a suitable ＂substrate＂. The triggers frequently occur at the border zone and the substrate is required for the maintenance of ischemic VE The critical factors for the initiation and maintenance of ischemic VF are obscure. Tumor necrosis factor-α （TNF-α）, an inflammatory cytokine expressed in myocardial ischemia, plays an important role in the pathophysiological process of acute myocardial infarction （AMI）. TNF-α also causes arrhythmia by action potential prolongation and abnormal Ca^2＋ handling, which also contribute to ischemic VE But the relationship between TNF-α and ischemic VF is unknown. In this article, we suggest that TNF-α may be a novel substrate of ischemic VE This may be a new mechanism for ischemic VF.

Ibutilide decreases defibrillation threshold by the reduction of activation pattern complexity during ventricular fibrillation in canine hearts

Background Ibutilide has been commonly used for pharmacologic cardioversion of atrial fibrillation and flutter in clinical settings. The objective of this study was to investigate the effects of ibutilide on the defibrillation threshold （DFT）, restitution properties, dispersion of refractoriness and activation patterns during ventricular fibrillation （VF）. Methods Ibutilide was administrated intravenously in six open-chest beagles. Before and after the drug administration, 20-second episodes of VF were electrically induced and recorded with a 10×10 unipolar electrode plaque sutured on the lateral epicardium of the left ventricle. DFT and VF activation patterns, including type of epicardial activation maps, VF cycle length （VF-CL）, conduction velocity, wavelength （WL） and reentry incidence, were measured. Restitution properties and dispersion of refractoriness were estimated from activation recovery intervals （ARI） during pacing. Results Compared to baseline, ibutilide markedly decreased the DFT by 31% （（491±14） V vs. （337±59） V, P 〈0.01）. The drug significantly reduced the maximal slope of the restitution curve （1.34±0.08 vs. 0.76±0.06, P 〈0.01） and its epicardial dispersion （0.36±0.09 vs. 0.21±0.06, coefficient of variation, P=0.03）. The dispersion of refractoriness was enhanced at the pacing cycle length of 300 ms to 160 ms by ibutilide. The drug significantly increased the VF-CL （（96±19） ms vs. （112±20） ms, P 〈0.01） and the WL （（41±9） mm vs. （52±14） mm, P=0.02） during VF, and reduced the reentry incidence by 25% （0.08±0.02 vs. 0.06±0.02, P 〈0.01）. In the epicardial activation maps, ibutilide significantly reduced the percentage of more complex activation maps during VF. Conclusions Intravenous ibutilide significantly decreased the DFT. It might be due to reduction of activation pattern complexity during VF.

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.

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.

Optimal antiarrhythmic drug therapy for electrical storm

Electrical storm, defined as 3 or more separate episodes of ventricular tachycardia or ventricular fibrillation within 24 hours, carries significant morbidity and mortality. These unstable ventricular arrhythmias have been described with a variety of conditions including ischemic heart disease, structural heart disease, and genetic conditions. While implantable cardioverter defibrillator implantation and ablation may be indicated and required, anti- arrhythmic medication remains an important adjunctive therapy for these persons.

Antiarrhythmic drugs and ventricular defibrillation energy requirements

Purpose To understand the potential interaction between antiarrhythmic therapy and the implantable cardioverter defibrillator (ICD) in patients who receive pharmacologic therapy as an adjunct to ICD therapy Data sources MEDLINE searching was employed and the information was indexed from approximately 3600 journals published world wide from 1966 to 1998 Study selection and data extraction Data were collected from 66 of approximately 455 originally identified articles and abstracts using explicit methodological criteria Results The ICD therapy has been widely used for therapy of life threatening ventricular arrhythmias (VT/VF) and prevention of recurrence of sudden cardiac death Studies reported that 40%-70% or 10%-40% of ICD patients required concomitant antiarrhythmic medication to reduce the frequency of sustained arrhythmic episodes and to minimize the frequency of device discharges Most studies on antiarrhythmic drug ICD interactions have been performed in experimental animals Antiarrhythmic drugs can influence the effectiveness of ICD to terminate arrhythmias through their effects on defibrillation threshold (DFT) Studies have demonstrated a rise in DFTs with class Ib agent lidocaine and class Ic agents encainide and flecainide Class Ia agents, as well as amiodarone, bretylium and propafenone may have more variable effects on DFT probably because of the difference between acute and chronic drug dosing, dose related changes, active metabolites, and reproducibility in determining DFT Class Ⅲ agents, with the exception of amiodarone, consistently decrease DFT These drugs can be used as front line agents in ICD patients Conclusions Antiarrhythmic drugs can increase, decrease, or have no effect on DFT Class Ⅲ agents except amiodarone can be safely administered in conjunction with ICD patients as long as the interaction between these therapeutic modalities is appreciated

Applying a global pulse disturbance to eliminate spiral waves in models of cardiac muscle

Removal of spiral waves in cardiac muscle is necessary because of their threat to life.Common methods for this removal are to apply a local disturbance to the media,such as a periodic forcing.However,most of these methods accelerate the beating of the cardiac muscle,resulting in the aggravation of the ventricular tachycardia,which directly threatens life.In the present study,in order to clear off spiral waves,a global pulse-disturbance is applied to the media based on three models of cardiac muscle.It is found that the spiral waves are eliminated and the frequency of the cardiac muscle is decreased in a short time,and finally,the state of the medium reaches the normal oscillation,which supports a target waves.Our method sheds light on the removal of spiral waves in cardiac muscle and can prevent the ventricular tachycardia as well as the ventricular fibrillation.

Effects of Testosterone on Norepinephrine Release in Isolated Rat Heart

The effects of testosterone on norepinephrine release were investigated in the isolated rat hearts.Sprague-Dawley male rats (n=120) were randomized to testosterone and control groups.The rats in testosterone group were perfused with modified Krebs-Henseleit buffer containing different concentrations of testosterone (0.1,1.0,10.0,and 100.0 nmol/L,respectively).Myocardial ischemia was induced by globally stopping the perfusion flow.Exocytotic norepinephrine release was induced by electrical field stimulation at 5 V (effective voltage) and 6 Hz (pulse width of 2 ms) for 1 min.The overflow of norepinephrine was determined by high pressure liquid chromatography and electrochemical detec-tion (HPLC-EC).Following acute ischemia,testosterone (1.0,10.0 and 100.0 nmol/L) significantly re-duced norepinephrine release (P<0.01),and the norepinepherine overflow was similar between the con-trol and 0.1 nmol/L testosterone group (P>0.05).Electrical stimulation of the ventricle evoked norepi-nepherine release,and this was diminished by the perfusion with testosterone at the concentrations of 1.0,10.0 and 100.0 nmol/L (P<0.01).It is suggested that testosterone suppresses ischemia-and electri-cal stimulationinduced norepinepherine release in the isolated rat hearts.

Brugada syndrome associated with out-of-hospital cardiac arrest: A case report

BACKGROUND Brugada syndrome(BrS)is an inherited disease characterized by an electrocardiogram(ECG)with a coved-type ST-segment elevation in the right precordial leads(V1-V3),which predisposes to sudden cardiac death(SCD)due to polymorphic ventricular tachycardia or ventricular fibrillation in the absence of structural heart disease.We report the case of a 29-year-old man with out-ofhospital cardiac arrest.BrS is associated with a high incidence of SCD in adults,and increasing the awareness of BrS and prompt recognition of the Brugada ECG pattern can be lifesaving.CASE SUMMARY A 29-year-old man suffered from out-of-hospital cardiac arrest,and after defibrillation,his ECG demonstrated a coved-type elevated ST segment in V1 and V2.These findings were compatible with type 1 Brugada pattern,and ECG of his brother showed a type 2 Brugada pattern.The diagnosis was BrS,NYHF IV,multiple organ dysfunction syndrome,sepsis,and hypoxic ischemic encephalopathy.The patient had no arrhythmia episodes after discharge throughout a follow-up period of 36 mo.CONCLUSION Increasing awareness of BrS and prompt recognition of the Brugada ECG pattern can be lifesaving.

Intra-procedural arrhythmia during cardiac catheterization: A systematic review of literature

BACKGROUND Cardiac catheterization is among the most performed medical procedures in the modern era.There were sporadic reports indicating that cardiac arrhythmias are common during cardiac catheterization,and there are risks of developing serious and potentially life-threatening arrhythmias,such as sustained ventricular tachycardia(VT),ventricular fibrillation(VF)and high-grade conduction disturbances such as complete heart block(CHB),requiring immediate interventions.However,there is lack of systematic overview of these conditions.AIM To systematically review existing literature and gain better understanding of the incidence of cardiac arrhythmias during cardiac catheterization,and their impact on outcomes,as well as potential approaches to minimize this risk.METHODS We applied a combination of terms potentially used in reports describing various cardiac arrhythmias during common cardiac catheterization procedures to systematically search PubMed,EMBASE and Cochrane databases,as well as references of full-length articles.RESULTS During right heart catheterization(RHC),the incidence of atrial arrhythmias(premature atrial complexes,atrial fibrillation and flutter)was low(<1%);these arrhythmias were usually transient and self-limited.RHC associated with the development of a new RBBB at a rate of 0.1%-0.3%in individuals with normal conduction system but up to 6.3%in individuals with pre-existing left bundle branch block.These patients may require temporary pacing due to transient CHB.Isolated premature ventricular complexes or non-sustained VT are common during RHC(up to 20%of cases).Sustained ventricular arrhythmias(VT and/or VF)requiring either withdrawal of catheter or cardioversion occurred infrequently(1%-1.3%).During left heart catheterizations(LHC),the incidence of ventricular arrhythmias has declined significantly over the last few decades,from 1.1%historically to 0.1%currently.The overall reported rate of VT/VF in diagnostic LHC and coronary angiography is 0.8%.The risk of VT/VF was higher during percutaneous coronary interventions for stable coronary artery disease(1.1%)and even higher for patients with acute myocardial infarctions(4.1%-4.3%).Intravenous adenosine and papaverine bolus for fractional flow reserve measurement,as well as intracoronary imaging using optical coherence tomography have been reported to induce VF.Although uncommon,LHC and coronary angiography were also reported to induce conduction disturbances including CHB.CONCLUSION Cardiac arrhythmias are common and potentially serious complications of cardiac catheterization procedures,and it demands constant vigilance and readiness to intervene during procedures.