Small bowel capsule endoscopy in patients with cardiac pacemakers and implantable cardioverter defibrillators:Outcome analysis using telemetry review

AIM:To determine if there were any interactions between cardiac devices and small bowel capsules secondary to electromagnetic interference (EMI) in patients who have undergone small bowel capsule endoscopy (SBCE).METHODS:Authors conducted a chart review of 20 patients with a cardiac pacemaker (CP) or implantable cardioverter defibrillator (ICD) who underwent continuous electrocardiographic monitoring during their SBCE from 2003-2008.authors searched for unexplained electrocardiogram (ECG) findings,changes in CP andICD set parameters,any abnormality in transmitted capsule data,and adverse clinical events.RESULTS:There were no adverse events or hemodynamically significant arrhythmias reported.CP and ICD set parameters were preserved.The majority of ECG abnormalities were also found in pre-or post-SBCE ECG tracings and the CP behavior during arrhythmias appeared appropriate.Two patients seemed to have episodes of undersensing by the CP.However,similar findings were documented in ECGs taken outside the time frame of the SBCE.One patient was observed to have a low signal encountered from the capsule resulting in lack of localization,but no images were lost.CONCLUSION:Capsule-induced EMI remains a possibility but is unlikely to be clinically important.CPinduced interference of SBCE is also possible,but is infrequent and does not result in loss of images transmitted by the capsule.

Remote monitoring of implantable defibrillators is associated with fewer inappropriate shocks and reduced time to medical assessment in a remote and rural area

BACKGROUND Implantable cardioverter defibrillators(ICDs)and cardiac resynchronisation therapy with defibrillators(CRT-D)reduce mortality in certain cardiac patient populations.However,inappropriate shocks pose a problem,having both adverse physical and psychological effects on the patient.The advances in device technology now allow remote monitoring(RM)of devices to replace clinic follow up appointments.This allows real time data to be analysed and actioned and this may improve patient care.AIM To determine if RM in patients with an ICD is associated with fewer inappropriate shocks and reduced time to medical assessment.METHODS This was a single centre,retrospective observational study,involving 156 patients implanted with an ICD or CRT-D,followed up for 2 years post implant.Both appropriate and inappropriate shocks were recorded along with cause for inappropriate shocks and time to medical assessment.RESULTS RM was associated with fewer inappropriate shocks(13.6%clinic vs 3.9%RM;P=0.030)and a reduced time to medical assessment(15.1±6.8 vs 1.0±0.0 d;P<0.001).CONCLUSION RM in patients with an ICD is associated with improved patient outcomes.

Interference between pacemakers/implantable cardioverter defibrillators and video capsule endoscopy

Our Letter to the Editor, related to the article "Small bowel capsule endoscopy in patients with cardiac pacemakers and implantable cardioverter defibrillators: Outcome analysis using telemetry" by Cuschieri et al , comments on some small errors, that slipped into the authors discussions. The given informations concerning the pacemakerand implantable cardioverter defibrillators modes were inaccurate and differ between the text and the table. Moreover, as 8 of 20 patient's pacemakers were programmed to VOO or DOO ("interference mode") and one patient was not monitored by telemetry during capsule endoscopy, 9 of 20 patients (45%) lack the informations of possible interference between capsule endoscopy their implanted device. Another objection refers to the interpretation of an electrocardiogram (figure 1, trace B) presented: in contrast to the author's opinion the marked spike should be interpreted as an artefact and not as "undersensing of a fibrillatory wave". Finally, three comments to cited reviews were not complete respectively not quoted correctly.

Analysis of daily activity data from implanted cardiac defibrillators: The minimum clinically important difference and relationship to mortality/life expectancy

Background: Daily activity is a potentially important measure for assessing prognosis in individuals with chronic heart failure (CHF), and few studies have investigated the prognostic value of daily activity measurement. The present study sought to determine whether there is an association between daily activity and mortality/mean life expectancy as predicted by the Seattle Heart Failure Model (SHFM), and to provide an estimate of the anchor-based minimum clinically important difference (MCID) for daily activity measured by single-axis accelerometers in implanted cardiac defibrillators. Methods: This study utilized a retrospective chart review of 102 medical records of patients with CHF and Medtronic? implanted cardiac defibrillators (ICDs). Mean daily activity was calculated for a two week period prior to both a baseline and follow-up routine clinical visit. Clinical characteristics from the baseline clinic visit were used for calculating SHFM estimates of mean life expectancy, 1-year mortality, and 5-year mortality. A five-point global rating scale was scored based on documented clinician impression, patient self-report, and laboratory and cardiographic tests for determining the MCID. Results: There was a moderate correlation between baseline daily activity and each of the SHFM prognostic indicators: 1-year mortality (r = 0.36, p < 0.001, 5-year mortality (r = 0.40, p < 0.001), and life expectancy (r = 0.43, p < 0.001). The MCID for a decline in daily activity was approximately 0.5 hours and was approximately 1.0 hours for improvement in daily activity. Conclusions: Although previous re- search has established the short-term predictive value of ICD-measured daily activity for CHF-related clinical events, no prior study has examined the longer-term prognostic value of ICD-based daily activity. The results of the present study suggest that low daily activity, as recorded by ICDs in patients with CHF, should prompt a more formal evaluation of prognosis using the SHFM. Furthermore, changes of 0.5 to 1.0 hours of activity per day appear to be clinically mean- ingful.

Igor V. Venin Founder of Biphasic Waveform Defibrillators

Igor V. Venin since 1966 and up till now has been an outstanding engineer of the Soviet Union and Ukraine, who has dedicated all his life to defibrillators development. Under his guidance 16 models of DC defibrillators with different waveforms, including the world’s first defibrillator with biphasic waveform (1971) have been developed and put into commercial production.

Intrahospital Dissemination of Automatic External Defibrillators Decrease Time to Defibrillation of In-Hospital Cardiac Arrests

Background: Survival rates for in-hospital cardiac (IHCA) arrest are low. Early defibrillation is vital and international guidelines, which requests defibrillation within three minutes. Can dissemination of automatic external defibrillators (AED) at hospital wards shorten time to defibrillation compared to standard care, calling for medical emergency team (MET)? Material & Methods: Forty-eight (48) units at S?dersjukhuset, Sweden, were included in the study. They were divided into the intervention group (24 units equipped with AEDs) and the standard care group (24 units with no AEDs). Intervention group staff were trained in CPR to use AEDs and standard care group staff were trained in just CPR. Data were gathered from patient records, AEDs and the Swedish National Registry of Cardiopulmonary Resuscitation (NRCR). Results: 126 IHCA patients were included, 47 in the standard care group, 79 in the intervention group. AEDs in the intervention group were connected to a defibrillator and it was ready to shock before arrival of MET in 83.5% of all cases. AEDs were ready to be used on average 96 seconds (14-427 s) before arrival of MET. Seven (15%) patients were defibrillated in the control group and Twenty (25%) in the intervention group. Defibrillation within three minutes occurred in 67% in the intervention group (11/17), compared with none (0/7) in the control group (p = 0.02). Conclusion: A systematic implementation of AEDs in hospital wards decrease time to defibrillation compared to a standard MET response system. Larger studies are needed to evaluate the impact on the outcome.

Incidence and causes of inappropriate detection and therapy by implantable defibrillators of cardioversion in patients with ventricular tachyarrhythmia

Background Implantable cardioverter defibrillator （ICD） is the only effective therapy in patients with life threatening ventricular arrhythmias. Inappropriate detection and therapy by ICDs are the most common causes of side effects that affect the quality of life in ICD recipients. This study evaluated the incidence and causes of inappropriate detection and therapy by ICDs in patients in our hospital. Methods From January 2000 to December 2005, fifty patients who received ICD implantation for ventricular arrhythmias for prevention of sudden cardiac death were evaluated in this study. Each ICD was programmed using clinical arrhythmic and cardiac data of the patient before discharge. Patients were followed up by standard schedule after implantation and all data retrieved from each device were collected and saved for further analysis. Results No arrhythmic event was detected in 12/50 （24%） patients during the period of follow-up. Among the remaining patients, 11 （22%） experienced inappropriate detections and therapies during follow-up in this study. ICD detected 383 ventricular tachyarrhythmia （VT） and 108 ventricular fibrillation （VF） episodes and delivered 678 therapies. In VT group, ICD delivered 413 antitachycardiac pacings （ATPs） and 118 shocks, among which 78 ATPs and 9 shocks were initiated by 55/383 （14.3%） inappropriate detections. In VF group ICD delivered 147 shocks, among which 56 shocks were initiated by 28/108 （26.9%） inappropriate detections. Overall, more than 50% of these episodes were caused by atrial fibrillation （AF） with rapid ventricular response, followed by electromagnetic or myopotential interference. In addition, most inappropriate therapies occurred within one year after ICD implantation. Conclusions About one fifth of patients experienced ICD inappropriate detection and therapy after implantation. The main cause was AF with rapid ventricular response, followed by electromagnetic or myopotential interference.

Risk factors for sudden cardiac death to determine high risk patients in specific patient populations that may benefit from a wearable defibrillator

BACKGROUND There is a high risk for sudden cardiac death(SCD) in certain patient groups that would not meet criteria for implantable cardioverter defibrillator(ICD) therapy.In conditions such as hypertrophic cardiomyopathy(HCM) there are clear risk scores that help define patients who are high risk for SCD and would benefit from ICD therapy. There are however many areas of uncertainty such as certain patients post myocardial infarction(MI). These patients are high risk for SCD but there is no clear tool for risk stratifying such patients.AIM To assess risk factors for sudden cardiac death in major cardiac disorders and to help select patients who might benefit from Wearable cardiac defibrillators(WCD).METHODS A literature search was performed looking for risk factors for SCD in patients post-MI, patients with left ventricular systolic dysfunction(LVSD), HCM, long QT syndrome(LQTS). There were 41 studies included and risk factors and the relative risks for SCD were compiled in table form.RESULTS We extracted data on relative risk for SCD of specific variables such as age,gender, ejection fraction. The greatest risk factors for SCD in post MI patients was the presence of diabetes [Hazard ratio(HR) 1.90-3.80], in patient with LVSD was ventricular tachycardia(Relative risk 3.50), in LQTS was a prolonged QTc(HR36.53) and in patients with HCM was LVH greater than 20 mm(HR 3.10). A proportion of patients currently not suitable for ICD might benefit from a WCDCONCLUSION There is a very high risk of SCD post MI, in patients with LVSD, HCM and LQTS even in those who do not meet criteria for ICD implantation. These patients may be candidates for a WCD. The development of more sensitive risk calculators to predict SCD is necessary in these patients to help guide treatment.

Role of nuclear cardiology for guiding device therapy in patients with heart failure

Heart failure is a dynamic condition with high morbidity and mortality and its prognosis should be reassessed frequently, particularly in patients for whom critical treatment decisions may depend on the results of prognostication. In patients with heart failure, nuclear cardiology techniques are useful to establish the etiol-ogy and the severity of the disease, while fewer studies have explored the potential capability of nuclear cardi-ology to guide cardiac resynchronization therapy （CRT） and to select patients for implantable cardioverter defbrillators （ICD）. Left ventricular synchrony may be assessed by radionuclide angiography or gated single-photon emission computed tomography myocardial perfusion scintigraphy. These modalities have shown promise as predictors of CRT outcome using phase analysis. Combined assessment of myocardial viability and left ventricular dyssynchrony is feasible using posi-tron emission tomography and could improve conven-tional response prediction criteria for CRT. Preliminary data also exists on integrated positron emission tomog-raphy/computed tomography approach for assessing myocardial viability, identifying the location of biven-tricular pacemaker leads, and obtaining left ventricular functional data, including contractile phase analysis. Fi-nally, cardiac imaging with autonomic radiotracers may be useful in predicting CRT response and for identifying patients at risk for sudden cardiac death, therefore po-tentially offering a way to select patients for both CRT and ICD therapy. Prospective trials where imaging is combined with image-test driven therapy are needed to better defne the role of nuclear cardiology for guiding device therapy in patients with heart failure.

Comparison of partners-heart failure algorithm vs care alert in remote heart failure management

AIM: To compare the utility of the partners-heart failure(HF) algorithm with the care alert strategy for remote monitoring,in guiding clinical actions oriented to treat impending HF.METHODS: Consecutive cardiac resynchronizationdefibrillator recipients were followed with biweekly automatic transmissions. After every transmission,patients received a phone contact in order to check their health status,eventually followed by clinical actions,classified as "no-action","non-active" and "active". Active clinical actions were oriented to treat impending HF. The sensitivity,specificity,positive and negative predictive values and diagnostic accuracy of the partners-HF algorithm vs care alert in determining active clinical actions oriented to treat pre-HF status and to prevent an acute decompensation,were also calculated.RESULTS: The study population included 70 patients with moderate to advanced systolic HF and QRS duration longer than 120 ms. During a mean follow-up of 8 ± 2 mo,665 transmissions were collected. No deaths or HF hospitalizations occurred. The sensitivity and specificity of the partners-HF algorithm for active clinical actions oriented to treat impending HF were 96.9%(95%CI: 0.96-0.98) and 92.5%(95%CI: 0.90-0.94) respectively. The positive and negative predictive values were 84.6%(95%CI: 0.82-0.87) and 98.6%(95%CI: 0.98-0.99) respectively. The partners-HF algorithm had an accuracy of 93.8%(95%CI: 0.92-0.96) in determining active clinical actions. With regard to active clinical actions,care alert had a sensitivity and specificity of 11.05%(95%CI: 0.09-0.13) and 93.6% respectively(95%CI: 0.92-0.95). The positive predictive value was 42.3%(95%CI: 0.38-0.46); the negative predictive value was 71.1%(95%CI: 0.68-0.74). Care alert had an accuracy of 68.9%(95%CI: 0.65-0.72) in determining active clinical actions.CONCLUSION: The partners-HF algorithm proved higher accuracy and sensitivity than care alert in determining active clinical actions oriented to treat impending HF. Future studies in larger populations should evaluate partners-HF ability to improve HF-related clinical outcomes.

Arrhythmogenic ventricular cardiomyopathy:A paradigm shift from right to biventricular disease

Arrhythmogenic ventricular cardiomyopathy(AVC) isgenerally referred to as arrhythmogenic right ventricu-lar(RV) cardiomyopathy/dysplasia and constitutesan inherited cardiomyopathy.Affected patients maysuccumb to sudden cardiac death(SCD),ventriculartachyarrhythmias(VTA) and heart failure.Geneticstudies have identified causative mutations in genesencoding proteins of the intercalated disk that lead toreduced myocardial electro-mechanical stability.Theterm arrhythmogenic RV cardiomyopathy is somewhatmisleading as biventricular involvement or isolated leftventricular(LV) involvement may be present and thus abroader term such as AVC should be preferred.The di-agnosis is established on a point score basis accordingto the revised 2010 task force criteria utilizing imagingmodalities,demonstrating fibrous replacement throughbiopsy,electrocardiographic abnormalities,ventricu-lar arrhythmias and a positive family history includingidentification of genetic mutations.Although severarisk factors for SCD such as previous cardiac arrest,syncope,documented VTA,severe RV/LV dysfunctionand young age at manifestation have been identified,risk stratification still needs improvement,especially inasymptomatic family members.Particularly,the roleof genetic testing and environmental factors has to befurther elucidated.Therapeutic interventions include re-striction from physical exercise,beta-blockers,sotalol,amiodarone,implantable cardioverter-defibrillators andcatheter ablation.Life-long follow-up is warranted insymptomatic patients,but also asymptomatic carriersof pathogenic mutations.

Mismatch between Sites of Incidence of Out-of-Hospital Cardiac Arrest and Locations of Installed Automated External Defibrillator in the Tokyo Metropolitan Area

Background: Since 2004, the number of installed Automated External Defibrillator (AED) has been increased in Japan annually, the cumulative number of sold AED more than 600,000 units by 2016. Despite there have been about 130,000 out of hospital cardiac arrest annually, there have only 1302 cases delivered defibrillation by bystanders at the scene. Therefore, we investigate that number of AED installation and usage rate for Out of Hospital Cardiac Arrest (OHCA) patients. Methods: Retrospective metropolitan wide cohort study. Subject: Total 13,364 OHCA patients in the Tokyo Metropolitan area from Jan. 1 through Dec. 31 in 2012 were eligible for theses analyses. Also, OHCA occurrence place and AED usage rate were studied. Results: 82.8% of OHCA occurred at residences, 10% at outdoors, 6.4% at indoors, only 0.7% at schools. In the other hand, highest bystander’s CPR rates were found in sports facilities and schools (71.4%). The installation rate of AEDs in residences was 9.6%, instead of highest incidence for OHCA patients, school and sports institute made up 21.4% of AED installations, but only 1.0% of the incidences of cardiac arrest. We found that there is a mismatch between incidence sites of cardiac arrest and locations of installed AED. Discussion: It is essential to increase the number of AED installations. Furthermore, it is desirable to install AEDs in locations where cardiac arrest is liable to occur following guidelines for the proper placement of AEDs, and important to further spread BLS education among the general citizens.

Heart rate-adjusted PR as a prognostic marker of long-term ventricular arrhythmias and cardiac death in ICD/CRT-D recipients

Objective To evaluate the PR to RR interval ratio (PR/RR,heart rate-adjusted PR) as a prognostic marker for long-term ventricular arrhythmias and cardiac death in patients with implantable cardioverter defibrillator (ICDs) and cardiac resynchronization therapy with defibrillators (CRT-D).Methods We retrospectively analyzed data from 428 patients who had an ICD/CRT-D equipped with home monitoring.Baseline PR and RR interval data prior to ICD/CRT-D implantation were collected from standard 12-lead electrocardiograph,and the PR/RR was calculated.The primary endpoint was appropriate ICD/CRT-D treatment of ventricular arrhythmias (VAs),and the secondary endpoint was cardiac death.Results During a mean follow-up period of 38.8 ± 10.6 months,197 patients (46%) experienced VAs,and 47 patients (11%) experienced cardiac death.The overall PR interval was 160 ± 40 ms,and the RR interval was 866 ± 124 ms.Based on the receiver operating characteristic curve,a cut-off value of 18.5% for the PR/RR was identified to predict VAs.A PR/RR ≥ 18.5% was associated with an increased risk of VAs [hazard ratio (HR)= 2.243,95% confidence interval (CI)= 1.665–3.022,P < 0.001) and cardiac death (HR = 2.358,95%CI = 1.240–4.483,P = 0.009) in an unadjusted analysis.After adjustment in a multivariate Cox model,the relationship remained significant among PR/RR ≥ 18.5%,VAs (HR = 2.230,95%CI = 1.555–2.825,P < 0.001) and cardiac death (HR = 2.105,95%CI = 1.101–4.025,P = 0.024.Conclusions A PR/RR ≥ 18.5% at baseline can serve as a predictor of future VAs and cardiac death in ICD/CRT-D recipients.

Advances in clinical studies of cardiopulmonary resuscitation

BACKGROUND: The survival rate of patients after cardiac arrest(CA) remains lower since 2010 International Consensus on Cardiopulmonary Resuscitation(CPR) and Emergency Cardiovascular Care(ECC) was published. In clinical trials, the methods and techniques for CPR have been overly described. This article gives an overview of the progress in methods and techniques for CPR in the past years.DATA SOURCES: Original articles about cardiac arrest and CPR from MEDLINE(PubM ed) and relevant journals were searched, and most of them were clinical randomized controlled trials(RCTs).RESULTS: Forty-two articles on methods and techniques of CPR were reviewed, including chest compression and conventional CPR, chest compression depth and speed, defibrillation strategies and priority, mechanical and manual chest compression, advanced airway management, impedance threshold device(ITD) and active compression-decompression(ACD) CPR, epinephrine use, and therapeutic hypothermia. The results of studies and related issues described in the international guidelines had been testifi ed.CONCLUSIONS: Although large multicenter studies on CPR are still difficult to carry out, progress has been made in the past 4 years in the methods and techniques of CPR. The results of this review provide evidences for updating the 2015 international guidelines.

I-123 metaiodobenzylguanidine imaging for predicting ventricular arrhythmia in heart failure patients

Compared to antiarrhythmic drugs, implantable cardioverter defibrillator （ICD） leads to a more significant im- provement in preventing ventricular arrhythmia in heart failure patients. However, an important question has been raised that how to select appropriate patients for ICD therapy. 1-123 metaiodobenzylguanidine （MIBG） planar and SPECT imaging have shown great potentials to predict ventricular arrhythmia in heart failure patients by as- sessing the abnormalities of the sympathetic nervous system. Clinical trials demonstrated that several parameters measured from 1-123 MIBG planar and SPECT imaging, such as heart-to-mediastinum ratio, washout rate, defect score, and innervation/perfusion mismatch, predicted ventricular arrhythmias in heart failure patients. This paper introduces the current practice of ICD therapy and reviews the technical background of 1-123 MIBG planar and SPECT imaging and their clinical data in predicting ventricular arrhythmia.

Transvenous defibrillator implantation in a patient with persistent left superior vena cava

Persistent left superior vena cava(LSVC) can be incidentally detected during pacemaker implantation through left pectoral side.There is technical difficulty of optimal site pacing and lead stability for right ventricle lead in such situation.We hereby report a case of successful single-chamber implantable cardioverter defibrillator(ICD) implantation in a 50 years-old male with LSVC.The practical issues related with right ventricle lead implantation and pacing/defibrillation parameters for ICD device are discussed.

Riata silicone defibrillation lead with normal electrical measures at routine ambulatory check:The role of highvoltage shock testing

AIM To describe our experience with shock testing for the evaluation of patients with Riata? leads.METHODS Among 51 patients with normal baseline electrical parameters, 20 died during follow-up. Of the remaining 31 patients, 15 underwent the test: In 10 cases a defibrillation testing with ventricular fibrillation(VF) induction and in 5 cases a R-wave-synchronized shock(> 20 J, without inducing VF). The test was performed under sedation with Midazolam. RESULTS Twelve patients(80%) had a normal behavior during shock testing: In 8 cases induced VF was correctly detected and treated; in 4 cases of R-wave-synchronized shock electrical parameters remained stable and normal. Three patients(20%) failed the test. One patient with externalized conductors showed a sudden drop of high-voltage impedance(< 10 Ohm) after a 25 J R-wave-synchronized shock. Two other patients with externalized conductors, undergoing defibrillation testing, showed a short-circuit during shock delivery and the implantable cardioverter defibrillator was unable to interrupt VF.CONCLUSION In Riata? leads the delivery of a low current during routine measurement of high-voltage impedance may not reveal a small short circuit, that can only be evident by attempting to deliver a true shock, either for spontaneous arrhythmias or in the context of a shock testing.

Single lead catheter of implantable cardioverterdefibrillator with floating atrial sensing dipole implanted via persistent left superior vena cava

Persistent left superior vena cava(LSVC) is a congenital anomaly with 0.3%-1% prevalence in the general population. It is usually asymptomatic but in case of transvenous lead positioning, i.e., for pacemaker or implantable cardioverter defibrillator(ICD), may be a cause for significant complications or unsuccessful implantation. Single lead ICD with atrial sensing dipole(ICD DX) is a safe and functional technology in patients without congenital abnormalities. We provide a review of the literature and a case report of successful implantation of an ICD DX in a patient with LSVC and its efficacy in treating ventricular arrhythmias.

Effectiveness of combining manual external defibrillator and automated external defibrillator training for third-year nurse students

Purpose:To assess the effectiveness of automated external defibrillator(AED)and manual external defibrillator(MED)training for third-year nurse students.Methods:We conducted post-demonstration and post-practice evaluation for MED defibrillation,and pre-training,post-demonstration,and post-practice evaluation for AED defibrillation.Results:Following MED training,time and confidence to defibrillate were improved significantly post-practice(p<0.001,p<0.001,respectively).In post-demonstration and postpractice evaluation,most students placed electrodes correctly(84.21%vs.80.70%),cleared before defibrillation(75.44%vs.89.47%),and performed cardiopulmonary resuscitation immediately after defibrillation(81.81%vs.94.44%);the evaluations were not statistically different(p=0.806,p=0.094,p=0.198,respectively).For AED training,time and confidence to defibrillate post-demonstration and post-practice were significantly improved(p<0.001 vs.p<0.001;p<0.001 vs.p<0.001,respectively)compared to that of pre-training;there was no obvious difference between the post-demonstration and postpractice evaluation(p=0.235,=0.346,respectively).Post-AED demonstration,most students could place electrodes correctly(85.96%),clear(91.23%),and perform CPR immediately after defibrillation(85.96%),which remained at a high level post-practice(94.74%,85.96%,82.46%,respectively);there was no significant difference between the two evaluations(p=0.203,p=0.557,p=0.776,respectively).Conclusion:Combining MED and AED defibrillation training is effective and feasible for third-year nurse students.Minimal training is effective for AED,while MED requires additional practice.

Layperson’s performance on an unconversant type of AED device:A prospective crossover simulation experimental study

BACKGROUND:Diverse models of automated external defibrillators(AEDs)possess distinctive features.This study aimed to investigate whether laypersons trained with one type of AED could intelligently use another initial contact type of AED with varying features.METHODS:This was a prospective crossover simulation experimental study conducted among college students.Subjects were randomly trained with either AED1(AED1 group)or AED2(AED2 group),and the AED operation performance was evaluated individually(Phase I test).At the 6-month follow-up AED performance test(Phase II test),half of the subjects were randomly switched to use another type of AED,which formed two switches(Switch A:AED1-1 group vs.AED2-1 group;Switch B:AED2-2 group vs.AED1-2 group).RESULTS:A total of 224 college students participated in the study.In the phase I test,a significantly higher proportion of successful defibrillation and shorter shock delivery time to achieve successful defibrillation was observed in the AED2 group than in the AED1 group.In the phase II test,no statistical differences were observed in the proportion of successful defibrillation in Switch A(51.4%vs.36.6%,P=0.19)and Switch B(78.0%vs.53.7%,P=0.08).The median shock delivery time within participants achieving successful defibrillation was significantly longer in the switched group than that of the initial group in both Switch A(89[81-107]s vs.124[95-135]s,P=0.006)and Switch B(68[61.5-81.5]s vs.95.5[55-131]s,P<0.001).CONCLUSION:College students were able to effectively use AEDs different from those used in the initial training after six months,although the time to shock delivery was prolonged.