Effective date of requirement for premarket approval for an implantable pacemaker pulse generator. Final rule

The Food and Drug Administration (FDA) is issuing a final rule to require the filing of a premarket approval application (PMA) or a notice of completion of a product development protocol (PDP) for implantable pacemaker pulse generators. The Agency has summarized its findings regarding the degree of risk of illness or injury designed to be eliminated or reduced by requiring this device to meet the statute's approval requirements and the benefits to the public from the use of the devices. This action implements certain statutory requirements.

Sudden cardiac death in dialysis: do current guidelines for implantable cardioverter defibrillator therapy apply to patients with end-stage kidney disease?

Arrhythmic mechanisms account for one in four deaths in end-stage kidney disease. Large-scale randomized controlled trials have demonstrated a mortality benefit from implantable cardioverter defibrillator therapy in carefully selected patient groups at high risk for sudden cardiac death. Unfortunately, patients with end-stage kidney disease were systematically excluded from these trials. Consequently, the applicability of American College of Cardiology (ACC)/American Heart Association (AHA)/Heart Rhythm Society (HRS) guidelines on implantable cardioverter defibrillator therapy to dialysis patients remains uncertain. Observational data suggest that secondary preventative implantable cardioverter defibrillator therapy following resuscitated cardiac arrest prolongs the lives of dialysis patients. This intervention may also offer a survival advantage as a primary preventative strategy in end-stage kidney disease. However, competing risk from co-morbidity can negate any perceived benefit. Device-related complications also negatively impact outcome. The recommendation that primary preventative device implantation be reserved for patients with severely impaired left ventricular function may be excessively restrictive in this high-risk population. Trials of implantable cardioverter defibrillator therapy that include dialysis patients are required to validate existing device eligibility criteria in this unique population. Novel indications for this intervention in dialysis patients should also be identified.

[Comments on the 2010 guidelines on cardiopulmonary resuscitation of the European Resuscitation Council]

ADULTS

Administer chest compressions (minimum 100/min, minimum 5 cm depth) at a ratio of 30:2 with ventilation (tidal volume 500-600 ml, inspiration time 1 s, F(I)O₂ if possible 1.0). Avoid any interruptions in chest compressions. After every single defibrillation attempt (initially biphasic 120-200 J, monophasic 360 J, subsequently with the respective highest energy), chest compressions are initiated again immediately for 2 min independent of the ECG rhythm. Tracheal intubation is the optimal method for securing the airway during resuscitation but should be performed only by experienced airway management providers. Laryngoscopy is performed during ongoing chest compressions; interruption of chest compressions for a maximum of 10 s to pass the tube through the vocal cords. Supraglottic airway devices are alternatives to tracheal intubation. Drug administration routes for adults and children: first choice i.v., second choice intraosseous (i.o.). Vasopressors: 1 mg epinephrine every 3-5 min i.v. After the third unsuccessful defibrillation amiodarone (300 mg i.v.), repetition (150 mg) possible. Sodium bicarbonate (50 ml 8.4%) only for excessive hyperkaliemia, metabolic acidosis, or intoxication with tricyclic antidepressants. Consider aminophylline (5 mg/kgBW). Thrombolysis during spontaneous circulation only for myocardial infarction or massive pulmonary embolism; during on-going cardiopulmonary resuscitation (CPR) only when indications of massive pulmonary embolism. Active compression-decompression (ACD-CPR) and inspiratory threshold valve (ITV-CPR) are not superior to good standard CPR.

CHILDREN

Most effective improvement of outcome by prevention of full cardiorespiratory arrest. Basic life support: initially five rescue breaths, followed by chest compressions (100-120/min depth about one third of chest diameter), compression-ventilation ratio 15:2. Foreign body airway obstruction with insufficient cough: alternate back blows and chest compressions (infants), or abdominal compressions (children >1 year). Treatment of potentially reversible causes: ("4 Hs and 4 Ts") hypoxia and hypovolaemia, hypokalaemia and hyperkalaemia, hypothermia, and tension pneumothorax, tamponade, toxic/therapeutic disturbances, thrombosis (coronary/pulmonary). Advanced life support: adrenaline (epinephrine) 10 µg/kgBW i.v. or i.o. every 3-5 min. Defibrillation (4 J/kgBW; monophasic or biphasic) followed by 2 min CPR, then ECG and pulse check. NEWBORNS: Initially inflate the lungs with bag-valve mask ventilation (p(AW) 20-40 cmH₂O). If heart rate remains <60/min, start chest compressions (120 chest compressions/min) and ventilation with a ratio 3:1. Maintain normothermia in preterm babies by covering them with foodgrade plastic wrap or similar. POSTRESUSCITATION PHASE: Early protocol-based intensive care stabilization; initiate mild hypothermia early regardless of initial cardiac rhythm [32-34°C for 12-24 h (adults) or 24 h (children); slow rewarming (<0.5°C/h)]. Consider percutaneous coronary intervention (PCI) in patients with presumed cardiac ischemia. Prediction of CPR outcome is not possible at the scene, determine neurological outcome <72 h after cardiac arrest with somatosensory evoked potentials, biochemical tests and neurological examination. ACUTE CORONARY SYNDROME: Even if only a weak suspicion of an acute coronary syndrome is present, record a prehospital 12-lead ECG. In parallel to pain therapy, administer aspirin (160-325 mg p.o. or i.v.) and clopidogrel (75-600 mg depending on strategy); in ST-elevation myocardial infarction (STEMI) and planned PCI also prasugrel (60 mg p.o.). Antithrombins, such as heparin (60 IU/kgBW, max. 4000 IU), enoxaparin, bivalirudin or fondaparinux depending on the diagnosis (STEMI or non-STEMI-ACS) and the planned therapeutic strategy. In STEMI define reperfusion strategy depending on duration of symptoms until PCI, age and location of infarction. TRAUMA: In severe hemorrhagic shock, definitive control of bleeding is the most important goal. For successful CPR of trauma patients a minimal intravascular volume status and management of hypoxia are essential. Aggressive fluid resuscitation, hyperventilation and excessive ventilation pressure may impair outcome in patients with severe hemorrhagic shock.

TRAINING

Any CPR training is better than nothing; simplification of contents and processes is the main aim.

ERC 2010 guidelines for adult and pediatric resuscitation: summary of major changes

The new European Resuscitation Council (ERC) guidelines for cardiopulmonary resuscitation (CPR) published on October 18th, 2010, replace those published in 2005 and are based on the latest International Consensus on CPR Science with Treatment Recommendations (CoSTR). For both adult and pediatric resuscitation, the most important general changes include: the introduction of chest compression-only CPR in primary cardiac arrest as an option for rescuers who are unable or unwilling to perform expired-air ventilation; increased emphasis on uninterrupted, good-quality CPR and minimisation of both pre- and post-shock pauses during defibrillation. For adult resuscitation, the recommended chest compression depth and rate are 5-6 cm and 100-120 compressions per minute, respectively. Both a specific period of CPR before defibrillation during out-of-hospital resuscitation and use of endotracheal route for drug delivery during advanced life support are no longer recommended. During postresuscitation care, inspired oxygen should be titrated to obtain an arterial oxygen saturation of 94-98%, to avoid possible damage from hyperoxemia. In pediatric resuscitation, the role of pulse palpation for the diagnosis of cardiac arrest has been de-emphasised. The compression-to-ventilation ratio depends on the number of rescuers available, and a 30:2 ratio is acceptable even for rescuers with a duty to respond if they are alone. Chest compression depth should be at least 1/3 of the anterior-posterior chest diameter. The use of automated external defibrillators for children under one year of age should be considered.

The AED in resuscitation: it's not just about the shock

The automated external defibrillator (AED), in combination with effective cardiopulmonary resuscitation (CPR), is a critical part of the American Heart Association's "Chain of survival." Newer guidelines have simplified resuscitation and emphasized the importance of CPR in providing rapid and deep compressions with minimal interruptions; in fact, CPR should resume immediately after the shock given by the AED, without the delay entailed in checking for pulse or rhythm conversion. Our experience with the AED aboard aircraft, showing 40% long-term survival with the AED in ventricular fibrillation, demonstrated the safety and efficacy of the device. Despite this and other reports of successful AED deployment, AEDs are not yet available at all public locations. Prospective research, as undertaken by the Resuscitation Outcomes Consortium, will be the key to future refinements of the guidelines and enhanced survival with use of the AED in sudden cardiac arrest.

[First-year medical residents' self-assessment of skill in basic life support and automatic external defibrillation]

OBJECTIVE

To determine first-year medical residents' perception of their competence in basic life support (BLS) and the use of automatic external defibrillation (AED).

MATERIAL AND METHODS

Course in BLS and AED accredited by the European Resuscitation Council with pre- and post-course self-assessment. The post-training questionnaire was administered immediately after the course and 8 months later. The data recorded covered (a) prior training and experience, (b) self-assessment of BLS and AED skills (9 items, scored 1-5), (c) the skill considered most difficult, and (d) satisfaction (13 items, scored 0-10).

RESULTS

The questionnaire was initially completed by 71 residents; 31 also responded 8 months later. Self-assessment scores improved immediately after the course (P = .0001). Scores had fallen 8 months later (P = .0001) but were still significantly higher than pre-course perception of skill (P = .017). More than 95% of the residents considered themselves to be competent after the course and more than 80% felt competent 8 months later, with the exception of skills in bag-mask ventilation (74.2%) and removal of a foreign body (61.3%). The skill considered most difficult was bag-mask ventilation. Mean (SD) BLS and AED scores for real-life situations were 8.48 (1.33) and 9.19 (0.94), respectively, after the course and 7.32 (1.4) and 7.29 (1.32) at 8 months (P = .0001). Overall satisfaction was high.

CONCLUSIONS

The residents perceived themselves as competent to give BLS and AED immediately after the course and 8 months after training, although fewer felt as competent at the second assessment. Bag-mask ventilation was considered the most difficult skill.

[Efficacy and safety of implantable cardioverter defibrillator avoiding routine defibrillation threshold testing]

OBJECTIVE

To evaluate the efficacy and safety of implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy-defibrillators (CRT-D) avoiding defibrillation threshold (DFT) testing when treating ventricular tachycardia (VT) or ventricular fibrillation (VF).

METHODS

We analyzed a continuous database of the 21 patients who had avoided DFT during ICD implantation from Oct. 1999 to Aug. 2008. Follow-up data were completed and analyzed in the 21 patients with ICD implantation.

RESULTS

ICDs were implanted successfully in 17 patients with VT or VF, and CRT-D were implanted successfully in 4 myocardiopathy patients with severe heart failure who avoided DFT during ICD or CRT-D implantation. Eight patients accepted DFT 1 week later, VT or VF was not induced in 3 patients (37.5%). During the mean follow-up of 1 approximately 7 (4.2+/-1.9) years, malignant ventricular arrythmia was recorded in 16 patients. Among them, 89 episodes were successfully terminated by defbrillation (100%), 120 VT events were terminated by the first run of antitachycardia pacing (51.1%) and 22 by low energy cardioversion (59.2%). All patients took antiarrhycardia drugs after ICD or CRT-D implantation. No patient died from malignant ventricular arrythmia during the follow-up.

CONCLUSION

No application of routine DFT may avoid complications associated with DFT during ICD or CRT-D implantation. ICD or CRT-D implantation may effectively treat fatal ventricular tachyarrhythmias and prevent sudden cardiac death.

The obstacles to maximising the impact of public access defibrillation: an assessment of the dispatch mechanism for out-of-hospital cardiac arrest

OBJECTIVES

To determine the diagnostic accuracy of advanced medical priority dispatch system (AMPDS) software used to dispatch public access defibrillation first responders to out-of-hospital cardiac arrests (OHCA).

DESIGN

All true OHCA events in North and West Belfast in 2004 were prospectively collated. This was achieved by a comprehensive search of all manually completed Patient Report Forms compiled by paramedics, together with autopsy reports, death certificates and medical records. The dispatch coding of all emergency calls by AMPDS software was also obtained for the same time period and region, and a comparison was made between these two datasets.

SETTING

A single urban ambulance control centre in Northern Ireland.

POPULATION

All 238 individuals with a presumed or actual OHCA in the North and West Belfast Health and Social Services Trust population of 138 591 (2001 Census), as defined by the Utstein Criteria.

MAIN OUTCOME MEASURES

The accurate dispatch of an emergency ambulance to a true OHCA.

RESULTS

The sensitivity of the dispatch mechanism for detecting OHCA was 68.9% (115/167, 95% confidence interval (CI) 61.3% to 75.8%). However, the sensitivity for arrests with ventricular fibrillation (VF) was 44.4% (12/27) with sensitivity for witnessed VF of 47.1% (8/17). The positive predictive value was 63.5% (115/181, 95% CI 56.1% to 70.6%).

CONCLUSIONS

The sensitivity of this dispatch process for cardiac arrest is moderate and will constrain the effectiveness of Public Access Defibrillation (PAD) schemes which utilise it.

TRIAL REGISTRATION

controlled-trials.com ISRCTN07286796.

Awareness of guidelines for use of automated external defibrillators in children within emergency medical services

BACKGROUND

Ventricular fibrillation occurs in 10-20% of pediatric cardiac arrests. Survival rates in children with ventricular fibrillation can be as high as 30% when the rhythm is identified and treated promptly. In the last 5 years, recommendations have been made for the use of automated external defibrillators in children between 1 and 8 years of age.

OBJECTIVE

The goal of this study was to determine the awareness of the ILCOR guidelines and statewide protocols concerning AED use in children ages 1-8 among emergency medical providers after new guideline release. Availability of pediatric capable AED equipment was also assessed.

METHODS

Surveys were distributed to EMS providers in Iowa and Montana within 1 year of the ILCOR advisory statement in 2003 recommending use of AEDs in children ages 1-8, and again approximately 1 year after the 2005 ILCOR guidelines on cardiopulmonary resuscitation were published. In Iowa, there were concentrated efforts to disseminate information about AED use in children, while there were minimal efforts in Montana.

RESULTS

Awareness of ILCOR guidelines for use of AEDs in children was low in both states in 2003 (29% in Iowa vs. 9% in Montana, p<0.001). After release of the 2005 guidelines, awareness improved significantly in both states but was still significantly greater in Iowa (83% vs. 60%, p<0.002). In 2003, less than 20% of respondents in both states reported access to pediatric capable AEDs. Availability of pediatric pads and cables increased significantly in 2006 but remained low in Montana (74% in Iowa vs. 37% in Montana, p<0.001).

CONCLUSIONS

At the present time, publication of new or interim guidelines in the scientific literature alone is insufficient to ensure that new protocols are implemented. An effective and efficient method to disseminate new pediatric out-of-hospital protocols emergency care to become standard of care in a timely matter must be developed.

PALS update 2005

Many of the changes in BLS recommended in 2005 Guidelines are designed to simplify CPR recommendations, increase the number and quality of chest compressions delivered, and increase the number of uninterrupted chest compressions. The recommendations for compressions have been summarized as, "Push harder, push faster, allow the chest to fully recoil, and stop only to use a bag mask to ventilate the patient, analyze the rhythm, deliver a shock or intubate. When such an interruption to compressions occurs, keep the length of that interruption to an absolute minimum. For lay rescuers, a single compression-ventilation ratio (30:2) for all age groups greatly simplifies the instructions for performing CPR. Recommendation of 1 Shock plus Immediate CPR for Attempted Defibrillation for cardiac arrest associated with VF or pulseless VT. Rescuers should not interrupt chest compressions to check circulation until about 5 cycles or approximately 2 minutes of CPR have been provided after the shock. The changes are designed to minimize interruptions in chest compressions. For Neonatal resuscitation, additional evidence was available about the use of oxygen versus room air for resuscitation, the need for clearing the airway of meconium, methods of assisting ventilation, techniques for confirming endotracheal tube placement, and use of the laryngeal mask airway (LMA).

[Adult cardio-respiratory arrest: guidelines 2005-2010]

At the end of 2005 the new guidelines for the treatment of cardiac arrest were published. The diagnostic criteria of cardiac arrest were simplified and priority is given to thoracic compressions. The ratio of thoracic compressions to insufflations is 30/2. The frequency of thoracic compression is 100/min. In ventricular tachycardia (VT) without pulse or in ventricle fibrillation (VF), defibrillation is attempted with a single external electric shock per cycle. The reanimation cycles are divided in periods of 2 minutes. The two drugs, used to treat VF and VT without pulse, are amiodarone and adrenaline. Adrenaline is not given before the fourth minute into the reanimation and it is administered before the third electrical external shock. In case of asystole or pulse less electrical activity adrenaline is administered as early as possible. Atropine is used in case of pulse less electrical activity with a ventricular response lower than 60/min. In advanced life support a priority is given to whether or not there are treatable secondary causes (4H, 4T), furthermore controlled hypothermia is installed when systemic circulation is restored and optimal support to all vital functions is given.

A written policy increases compliance with guidelines for therapeutic anticoagulation prior to elective direct current cardioversion of atrial fibrillation

BACKGROUND

Therapeutic anticoagulation before elective direct current cardioversion (DCC) of atrial fibrillation reduces the risk of embolic stroke. Direct current cardioversion is performed by a variety of practitioners, and variable adherence to preprocedural anticoagulation guidelines is common.

OBJECTIVE

We assessed the impact of a written policy on guideline compliance.

METHODS

: Anticoagulation status and transesophageal echocardiogram (TEE) results were reviewed in 55 patients (32 men/23 women; ages 18-83 years) who underwent elective DCC during the 6-month period before a written anticoagulation policy was sent to physicians who perform, prepare, or refer patients for this procedure. The nurse assigned to each DCC was responsible for documenting anticoagulation status. In accordance with guidelines, therapeutic anticoagulation was defined as a normalized ratio range > or = 2.0 for at least 3 weeks or a negative TEE with a normalized ratio range > or = 2.0 or a partial thromboplastin time > 50 seconds at the time of DCC. Immediately after policy implementation, anticoagulation status and TEE results were reviewed in 53 patients (42 men/11 women; ages 21-84 years) and 1 year post-policy implementation.

RESULTS

Before policy implementation, 14 of 52 patients (27%) had DCC performed without adequate anticoagulation or a negative TEE. Immediately postimplementation, only 2 of 50 patients (4%) had DCC performed without adequate anticoagulation or a negative TEE (P = .002). One year post-policy implementation, only 4 of 48 patients (8%) had DCC performed without adequate anticoagulation or a negative TEE (P = .03).

CONCLUSIONS

Implementing a written policy greatly reduces the number of patients undergoing DCC without adequate anticoagulation or a negative TEE. The impact of this intervention was quickly demonstrable and persisted during follow-up. Supplementing published recommendations with guideline-driven policies may reduce variations in clinical practice and improve quality of care.

Defibrillation during renal dialysis: A survey of UK practice and procedural recommendations

INTRODUCTION

Defibrillation of patients connected to medical equipment that is not defibrillation proof risks ineffective defibrillation and harm to the operator as a result of aberrant electrical pathways taken by the defibrillation current. Many renal dialysis systems are not currently defibrillation proof. Although national and international safety standards caution against defibrillating under this circumstance, it appears to be an area of confusion that we have investigated in more detail.

METHODS

Thirty renal dialysis units across the UK were invited to participate in a telephone survey of current practice from 1 October 2004 to 1 October 2005. The Medical Healthcare Regulatory Agency and renal dialysis machine manufacturers were contacted for advice, and current safety standards were reviewed.

RESULTS

Twenty-eight renal dialysis units completed the survey. Seven (25%) units would not disconnect patients from dialysis equipment during defibrillation, collectively reporting 14 patients who had required defibrillation during dialysis. Eighteen (64.3%) units would disconnect patients from dialysis equipment during defibrillation, collectively reporting 29 patients who had required defibrillation during dialysis. No complications were identified by this survey, through the MHRA or through a literature search.

CONCLUSION

Defibrillation of patients while undergoing renal dialysis is common practice in the UK. Although no adverse events have been reported, this practice risks injury to the patient and clinical staff, and equipment damage if the dialysis equipment is not defibrillation proof. It is in breach of national and international safety standards and should not be practiced.

Post-shock synchronized pacing in isolated rabbit left ventricle: evaluation of a novel defibrillation strategy

INTRODUCTION

A failed near-threshold defibrillation shock is followed by an isoelectric window (IEW) and rapid repetitive responses that reinitiate ventricular fibrillation (VF). We hypothesized that properly timed (synchronized) postshock pacing stimuli (SyncP) may capture the recovered tissues during the repetitive responses and prevent postshock reinitiation of VF, resulting in improved defibrillation efficacy.

METHODS AND RESULTS

We explored the effect of postshock SyncP on defibrillation efficacy in isolated rabbit hearts (n = 12). Optical recording-guided real-time detection and electrical stimulation (5 mA) of recovered tissues in anterior/posterior left ventricle (LV) were performed following IEW. The IEW duration was found to be 69 +/- 13 ms. With the same shock strength, successful and failed defibrillation episodes were associated with 50% and 15% of the myocardium, respectively, captured by the SyncP (P < 0.001). Electrical stimulation from the posterior LV resulted in 75% of episodes capturing myocardium, as compared with anterior LV stimulation (55%; P < 0.01) and higher successful defibrillation rate (14%, posterior vs. 3%, anterior LV). The overall success in terminating VF by postshock SyncP was approximately 10%. The causes for failed myocardium capture by postshock SyncP included lack of IEW after low-strength shock (42.9%), incorrect locations of reference site (25.7%) and pacing electrodes (17.9%), and others, such as wave breakthroughs (13.5%).

CONCLUSION

Postshock SyncP was feasible and the larger the myocardium captured area, the more likely was the successful defibrillation. Postshock SyncP delivered to the posterior LV was more effective than anterior LV to terminate VF.

Retention of skills in medical students following minimal theoretical instructions on semi and fully automated external defibrillators

AIM OF THE STUDY

There is consent that the use of automated external defibrillators (AED) by laypersons improves survival rates in case of cardiac arrest, but no evident consensus exists on the content and duration of training for this purpose. Acceptance of the implementation of Public Access Defibrillation programmes will depend on practical and target-oriented training concepts. The aim of this prospective randomised interventional study was to evaluate long-term effects of a specific, minimal training programme on using semiautomatic and fully automatic AEDs in simulated cardiac arrest.

MATERIALS AND METHODS

In a mock cardiac arrest scenario 59 medical students with no specific previous medical education were tested during their first semester at medical school. Students who passed any medical emergency training were excluded. The subjects were evaluated before and after attending specified instructions of 15 min duration and after a period of 6 months. Main end points were time to first shock, electrode-positioning and safety throughout the procedure.

RESULTS

Mean time to first shock without prior instructions was 77.7+/-17.05 s. After instruction there was a significant improvement to 56.5+/-9.5 s (p<or=0.01) and after 6 months this time had only slightly elongated (59.9+/-8.9 s; p<or=0.01). Initially, correct electrode placement was observed in 84.4%. No difference was found immediately and 6 months after instructions (93.2% and 98.3%). All individuals performed safely.

CONCLUSION

First year medical students with minimal instruction are able to use semiautomatic as well as fully automatic AED sufficiently fast and safe without prior training. A significant improvement in time to first shock can be detected up to 6 months after receiving non-specific instructions of 15 min duration.