Earliest recorded postshock myocardial activations in pigs originate in the subepicardium of the apex and lateral free wall of the left ventricle (LV) 30-90 ms after the shock. The purpose of this study was to determine whether the Purkinje system is a candidate for the source of postshock activations by ...

We hypothesize that remodelling of action potential and intracellular calcium (Ca(i)) dynamics in the peri-infarct zone contributes to ventricular arrhythmogenesis in the postmyocardial infarction setting. To test this hypothesis, we performed simultaneous optical mapping of Ca(i) and membrane potential (V(m)) in the left ventricle in 15 rabbit hearts with myocardial ...

BACKGROUND: With rapid improvements in technology and accumulation of clinical evidence, the implantable cardioverter defibrillator (ICD) has become a standard treatment for either primary or secondary prevention of sudden cardiac death. However, no analysis based on the perspective of emergency department has been reported, and managing patients with ICD remains ...

INTRODUCTION: Rapid defibrillation is the most effective strategy for establishing return of spontaneous circulation following cardiac arrest due to ventricular fibrillation. The aim of this study is to measure the delay due to of charging the defibrillator during chest compression in an attempt to reduce the duration of the pre-shock ...

Intrathoracic impedance measurement has been introduced in the InSync Sentry biventricular implantable cardioverter-defibrillator and may permit the early identification of pulmonary fluid accumulation secondary to left-sided heart failure (HF). An audible alarm (the OptiVol alert) can be triggered when the impedance index increases to greater than a predefined level of ...

A 45-year-old man was diagnosed with new-onset atrial fibrillation. Control of ventricular rate led to spontaneous conversion to sinus rhythm. Subsequent electrocardiograms revealed ST segment changes characteristic of Brugada syndrome. Electrophysiology study demonstrated inducible ventricular fibrillation. During the placement of an implantable cardiac defibrillator the patient was found to have ...

A 45-year-old man had life-threatening recurrent idiopathic ventricular fibrillation and persistent cardiogenic shock develop. The episodes of ventricular fibrillation were refractory to aggressive medical management; therefore an Abiomed AB5000 bi-ventricular support system was implanted for arrhythmia control. The device was able to maintain hemodynamic stability during the following 2 weeks. ...

A 40-year-old man was admitted to our institution with mild heart failure symptoms, including palpitations and near syncope. Twenty-eight years earlier, he had undergone a Mustard operation to correct d-transposition of the great vessels. At the present admission, echocardiography revealed severe right (systemic) ventricular dysfunction. Continuous monitoring also showed sinus-node ...

We present a case of a previously healthy 17 year-old white male boy scout who collapsed after a lightning strike, and was found to be in ventricular fibrillation when emergency medical services arrived. The ventricular fibrillation was defibrillated into sinus rhythm after a single direct current (DC) countershock. However, the ...

The outcome of acute myocardial infarction is usually settled before the patient reaches hospital, because ventricular fibrillation, when it occurs, is most common soon after the onset of symptoms. Ventricular fibrillation can be treated as effectively by ambulance personnel as in hospital, and many more deaths can be prevented, mainly ...

We report the first successful totally percutaneous pacing and defibrillation of a single ventricle in a 52-year-old woman who had undergone a classic Fontan operation (atriopulmonary connection) for tricuspid atresia 21 years earlier. Left ventricular pacing and sensing was obtained with a bipolar lead in the lateral cardiac vein, and ...

Cardiac arrest and sudden cardiac death remain major causes of mortality. Early intervention has been facilitated by emergency medical response systems and the development of training programs in basic life support and advanced cardiac life support (ACLS). Despite the implementation of these programs, the likelihood of a meaningful outcome in ...

OBJECTIVES: The effects of two clinically available biphasic waveforms on the success of defibrillation and postresuscitation myocardial dysfunction after prolonged ventricular fibrillation were compared with two newly designed dual-path sequential and simultaneous rectilinear biphasic waveforms. Defibrillation via sequential pulses and encircling, overlapping multiple pathway may depolarize a larger myocardial mass ...

We describe multiple failed external defibrillation attempts via rescue defibrillation pads for ventricular fibrillation that occurred secondary to direct electrical current transmission through the pericardial sac from electrocautery during robot-assisted internal mammary harvest. Only after resumption of two-lung ventilation and decompression of the iatrogenic pneumothorax was the patient successfully defibrillated. ...

Primary and secondary prevention of sudden cardiac death is not sufficiently assured by medication. The (automatic) implantable cardioverter/defibrillator ((A)ICD) is able to terminate life-threatening arrhythmias (ventricular fibrillation/flutter, ventricular tachycardia) reliably. The identification and care of risk patients is of crucial importance. Initially, only survived resuscitation for ventricular fibrillation or ventricular ...

BACKGROUND: Although biphasic, as compared with monophasic, waveform defibrillation for cardiac arrest is increasing in use and popularity, whether it is truly a more lifesaving waveform is unproven. METHODS AND RESULTS: Consecutive adults with nontraumatic out-of-hospital ventricular fibrillation cardiac arrest were randomly allocated to defibrillation according to the waveform from ...

This consensus paper on behalf of the Study Group on Sports Cardiology of the European Society of Cardiology follows a previous one on guidelines for sports participation in competitive and recreational athletes with supraventricular arrhythmias and pacemakers. The question of imminent life-threatening arrhythmias is especially relevant when some form of ...

AIMS: To investigate the feasibility and efficacy of novel low-tilt biphasic waveforms in transvenous cardioversion of atrial fibrillation (AF), delivered by a radiofrequency-powered defibrillator. METHODS AND RESULTS: The investigation was performed in three phases in an animal model of AF: a feasibility and efficacy study (in 10 adult Large White ...

OBJECTIVE: Postresuscitation myocardial dysfunction has been recognized as a leading cause of early death after initially successful cardiopulmonary resuscitation. We have previously demonstrated that opening adenosine triphosphate (ATP)-sensitive K (KATP) channels or activation of delta-opioid receptors minimized the severity of postresuscitation myocardial dysfunction and increased the duration of postresuscitation survival. ...

BACKGROUND: Cardiopulmonary resuscitation (CPR) and electrical defibrillation are the primary treatment options for ventricular fibrillation (VF). While recent studies have shown that providing CPR prior to defibrillation may improve outcomes, the effects of CPR quality remain unclear. Specifically, the clinical effects of compression depth and pauses in chest compression prior ...

Background Sudden cardiac death related to exercise is an uncommon problem, but is perhaps the single biggest challenge to sports medicine practitioners. Although the overall risk of death due to cardiac causes is substantially reduced in those who exercise regularly, the risk is temporarily increased during exercise. The causes of ...

Increasing numbers of patients with indwelling single- or dual- chamber internal cardioverter defibrillators (ICDs) will require upgrading of an existing system to a biventricular ICD providing cardiac resynchronization with back-up defibrillation. Upgrading, usually by the addition of a new left ventricular (LV) lead, can be technically challenging with central venous ...

OBJECTIVES: Implantable cardioverter defibrillators (ICDs) are highly effective at preventing cardiac arrest, but their availability is limited by high cost. Automated external defibrillators (AEDs) are likely to be less effective, but also less expensive. We used decision analysis to evaluate the clinical and economic trade-offs of AEDs, ICDs, and emergency ...

We performed a pilsicainide challenge test in a 38-year-old man who was resuscitated from ventricular fibrillation without apparent baseline electrocardiogram (ECG) abnormality. His father had a history of ventricular fibrillation and his brother had multiple episodes of syncope. Pilsicainide (1 mg/kg) induced short coupled ventricular premature beats followed by repetitive ...

BACKGROUND: Programmed electrical stimulation of the heart as a method to induce tachyarrhythmias has been described since the 1960s. To date, no study has examined optimal drive cycle length in the induction of ventricular fibrillation (VF) during defibrillation threshold testing after implantable cardioverter-defibrillator placement. We hypothesized that longer drive cycle ...

OBJECTIVE: The objective of this study was to document the biochemical changes during ventricular fibrillation (VF) with cardiopulmonary resuscitation (CPR), and to identify factors associated with postdefibrillation pulseless electrical activity (PD-PEA). BACKGROUND: It has been reliably estimated that as much as 60% of out-of-hospital sudden cardiac death can be attributed ...

AIMS: The development of implantable cardioverter-defibrillators (ICDs) with QRS morphology discrimination and dual-chamber sensing capabilities has improved the differentiation of supraventricular from ventricular tachycardias (VTs). Inappropriate ICD discharges may result from extracardiac signals caused by electromagnetic interference (EMI), because of electric fields and leakage currents from domestic or medical electrical ...

Current generations of implantable cardioverter defibrillators are capable of providing sophisticated dual chamber atrioventricular and rate-responsive pacing therapies, and even cardiac resynchronization therapy. Appropriate programming of the devices is necessary for them to perform all such sophisticated tasks. In this report, we describe a case where detection of ventricular tachycardia ...

The case of a 54-year-old patient with severe coronary artery disease and storms of ventricular tachyarrhythmias is presented. On the replacement of an implantable cardioverter defibrillator due to battery depletion, he suffered life-threatening complications associated with arrhythmia induction. Performing a routine induction of ventricular arrhythmias on the occasion of pulse ...

Despite considerable progress in the management of coronary artery disease and dilated cardiomyopathy, a substantial proportion of patients remains at the risk of life-threatening arrhythmic events. The Multicenter Automatic Defibrillator Implantation II and Sudden Cardiac Death Heart Failure studies have conclusively demonstrated that prophylactic implantable cardioverter-defibrillator (ICD) therapy reduces mortality ...

A persistent left superior vena cava was discovered in a 66-year-old man with heart failure undergoing implantation of a biventricular pacing and defibrillator device. An active fixation right ventricular defibrillator lead was placed through a curved guiding catheter. A sub-selection catheter and a guidewire allowed the engagement of a posterior-lateral ...

A paediatric patient with hypertrophic cardiomyopathy (HCM) presented cardiac arrest due to ventricular fibrillation. Ventricular arrhythmias were not induced in an electrophysiological study, but an implantable cardioverter defibrillator (ICD) was implanted. Nine months later, the child experienced a recurrence of cardiac arrest during exercise, which was successfully treated with a ...

OBJECTIVES: The study was designed to assess the effect of elapsed time from coronary revascularization (CR) on the benefit of the implantable cardioverter-defibrillator (ICD) and the risk of sudden cardiac death (SCD) in patients with ischemic left ventricular dysfunction. BACKGROUND: The ICD improves survival in appropriately selected high-risk cardiac patients ...

BACKGROUND: Atrial defibrillation can be achieved with a conventional dual-coil, active pectoral implantable cardioverter-defibrillator (ICD) lead system. Shocking vectors that incorporate an additional electrode in the CS have been used, but it is unclear if they improve atrial DFTs. OBJECTIVE: The objective of this prospective, randomized study was to determine ...

Implantable cardioverter defibrillators (ICDs) are frequently offered to patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). Yet ICDs in these patients may be complicated by poor sensed amplitudes resulting from fatty and fibrous tissue replacement of right ventricular myocardium. We present the case of a patient with ARVD/C who had inappropriate ...

BACKGROUND: As a result of longer follow-up after implantation of cardioverter defibrillators (ICD), fatigue of the leads has become a concern. The aim of this study was to determine the incidence and clinical presentation of ICD lead failures. METHODS AND RESULTS: The study population consisted of 241 patients with 249 ...

Aging is associated with structural alterations in the heart that predispose the elderly to life-threatening ventricular arrhythmias. The majority of sudden cardiac deaths occur in people aged 65 and older. As the proportion of elderly in our population continues to grow, a greater number of elderly patients with malignant ventricular ...

Successful defibrillation of a patient with dextrocardia using conventional anterolateral paddle positions raises doubts about the necessity to place paddles in the exact recommended positions. Evidence found relates either to volunteers in a laboratory setting or to defibrillation of atrial arrhythmias. The conclusion is that there is no published difference ...

BACKGROUND: Implantable cardioverter-defibrillator (ICD) lead failures often present as inappropriate shock therapy. An algorithm that can reliably discriminate between ventricular tachyarrhythmias and noise due to lead failure may prevent patient discomfort and anxiety and avoid device-induced proarrhythmia by preventing inappropriate ICD shocks. OBJECTIVES: The goal of this analysis was to ...

Numerous trials have demonstrated survival benefits using implantable cardioverter defibrillators (ICDs) for primary prevention in selected patients with left ventricular (LV) systolic dysfunction. However, eligibility criteria differed across these trials. Without a risk stratification scheme that clearly identifies those who will benefit, there remains debate about which patients with heart ...

Non-sustained and self-terminating arrhythmias pose a significant challenge during resuscitation. Delivery of a defibrillation shock to a non-shockable rhythm has a poorly understood effect on the heart. The importance of assessing rhythm right up until the delivery of a shock is of increased importance when "blind" shocks are being delivered ...

PURPOSE OF REVIEW: Arrhythmogenic right-ventricular dysplasia is a rare inherited disease characterized by right-ventricular dysfunction and ventricular arrhythmias. The purpose of this article is to review recent developments concerning the diagnosis, genetics, and management of patients with this disease. RECENT FINDINGS: In the past few years important new information has ...

INTRODUCTION: Pulseless ventricular tachycardia and ventricular fibrillation are the main causes of sudden cardiac death, but other ventricular tachyarrhythmias can occur without haemodynamic compromise. Ventricular arrhythmias occur mainly as a result of myocardial ischaemia or cardiomyopathies, so risk factors are those of cardiovascular disease. METHODS AND OUTCOMES: We conducted a ...

PURPOSE OF THE REVIEW: The aim of this article is to summarize the most relevant findings of recently published trials on prophylactic implantable cardioverter defibrillator therapy. RECENT FINDINGS: A number of important randomized clinical trials on the efficacy of prophylactic implantable cardioverter defibrillator therapy in patients deemed to be at ...

Implantable cardioverter-defibrillator (ICD or defibrillator) therapy has revolutionized the fields of cardiology and electrophysiology. Hundreds of thousands of patients at risk for sudden cardiac death receive them each year. The devices are not much larger than a pacemaker, and they have full pacemaker capabilities in addition to being able to ...

INTRODUCTION: Cardiovascular disease remains the most common cause of death in the United States and most other Western nations. Among these deaths, sudden, out-of-hospital cardiac arrest claims approximately 1000 lives each day in the United States alone. Most of these cardiac arrests are due to ventricular fibrillation. Though highly reversible ...

In this study, we have introduced the pattern classifier using the self-organizing map (SOM) for detecting fatal cardiac arrhythmia in implantable cardioverter-defibrillators (ICDs). The SOM has learned patterns of sinus rhythm, ventricular fibrillation and ventricular tachycardia with the feature vectors extracted from electrocardiogram and right ventricular volume measured during an ...

The likelihood of successful defibrillation in patients with sustained ventricular fibrillation (VF) is increased after administering thrombolytics during cardiopulmonary resuscitation (CPR). While dissolution of coronary artery thrombosis resolves the underlying cause of myocardial infarction in the majority of patients, improved microcirculatory reperfusion and alteration of the electrical activity of the ...

Optical mapping of electrical activity in the heart employs digital imaging and voltage-sensitive dyes. These methods have become an increasingly common research tools in basic cardiac electrophysiology. Significant advantages of this approach include simultaneous noncontact recording of entire action potentials free of electrical stimulus-induced artifacts from multiple closely adjacent sites, ...

Studies have investigated the effect of defibrillator paddle position on the efficacy of external electrocardioversion of atrial fibrillation, without agreeing upon an optimal placement. We wish to investigate using esophageal electric fields (EEFs) to predict atrial defibrillation thresholds (ADFTs) on a patient-specific basis. We propose to (1) investigate the relationship ...