Jose A. Joglar

Use of Automated External Defibrillators by a U.S. Airline

BACKGROUND Passengers who have ventricular fibrillation aboard commercial aircraft rarely survive, owing to the delay in obtaining emergency care and defibrillation. METHODS In 1997, a major U.S. airline began equipping its aircraft with automated external defibrillators. Flight attendants were trained in the use of the defibrillator and applied the device when passengers had a lack of consciousness, pulse, or respiration. The automated external defibrillator was also used as a monitor for other medical emergencies, generally at the direction of a passenger who was a physician. The electrocardiogram that was obtained during each use of the device was analyzed by two arrhythmia specialists for appropriateness of use. We analyzed data on all 200 instances in which the defibrillators were used between June 1, 1997, and July 15, 1999. RESULTS Automated external defibrillators were used for 200 patients (191 on the aircraft and 9 in the terminal), including 99 with documented loss of consciousness. Electrocardiographic data were available for 185 patients. The administration of shock was advised in all 14 patients who had electrocardiographically documented ventricular fibrillation, and no shock was advised in the remaining patients (sensitivity and specificity of the defibrillator in identifying ventricular fibrillation, 100 percent). The first shock successfully defibrillated the heart in 13 patients (defibrillation was withheld in 1 case at the familys request). The rate of survival to discharge from the hospital after shock with the automated external defibrillator was 40 percent. A total of 36 patients either died or were resuscitated after cardiac arrest. No complications arose from use of the automated external defibrillator as a monitor in conscious passengers. CONCLUSIONS The use of the automated external defibrillator aboard commercial aircraft is effective, with an excellent rate of survival to discharge from the hospital after conversion of ventricular fibrillation. There are not likely to be complications when the device is used as a monitor in the absence of ventricular fibrillation.

2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

Jonathan L. Halperin, MD, FACC, FAHA, Chair Glenn N. Levine, MD, FACC, FAHA, Chair-Elect Jeffrey L. Anderson, MD, FACC, FAHA, Immediate Past Chair [¶][1] Nancy M. Albert, PhD, RN, FAHA[¶][1] Sana M. Al-Khatib, MD, MHS, FACC, FAHA Kim K. Birtcher, PharmD, AACC Biykem Bozkurt, MD, PhD, FACC

Treatment of Cardiac Arrhythmias During Pregnancy Safety Considerations

Maternal and fetal arrhythmias occurring during pregnancy may jeopardise the life of the mother and the fetus. When arrhythmias are well tolerated and patients are minimally symptomatic, conservative therapy, such as observation and rest or vagal manoeuvres, should be employed. When arrhythmias cause debilitating symptoms or haemodynamic compromise, antiarrhythmic drug therapy is indicated. Although no antiarrhythmic drug is completely safe during pregnancy, most are well tolerated and can be given with relatively low risk.Physiological changes that occur during pregnancy mandate caution when administering antiarrhythmic drugs, with close monitoring of serum concentration and patient response. Drug therapy should be avoided during the first trimester of pregnancy if possible, and drugs with the longest record of safety should be used as first-line therapy.Several therapeutic options exist for most arrhythmias in the mother and fetus. Of the class IA agents, quinidine has the longest record of safety during pregnancy, and is generally well tolerated. Procainamide is also well tolerated, and should be a first line option for acute treatment of undiagnosed wide complex tachycardia. All IA agents should be administered in the hospital under cardiac monitoring due to the potential risk of ventricular arrhythmias (torsade de pointes).The IB agent, lidocaine (lignocaine), has local anaesthetic role but is also generally well tolerated as an antiarrhythmic agents. Phenytoin should be avoided due to the high risk of congenital malformations and limited role as an antiar-rhythmic drug. Of the IC agents, flecainide has been shown to be very effective in treating fetal supraventricular tachycardia complicated by hydrops. β-Blockers are generally well tolerated and can be used with relative safety in pregnancy, although recent data suggest that they may cause intrauterine growth retardation if they are administered during the first trimester.Amiodarone, a class II agents with characteristics of the other antiarrhythmic drug classes, has been reported to cause congenital abnormalities; it should be avoided during the first trimester and used only to treat life-threatening arrhythmias that fail to respond to other therapies. Adenosine is generally safe to use in pregnancy, and is the drug of choice for acute termination of maternal supraventricular tachycardia. Digoxin has a long track record of treating both maternal and fetal arrhythmias, and is one of the safest antiarrhythmics to use during pregnancy.Direct current cardioversion to terminate maternal arrhythmias is well tolerated and effective, and should not be delayed if indicated. The use of an implantable cardioverter-defibrillator should be considered for women of childbearing potential with life-threatening ventricular arrhythmias.

Initial energy for elective external cardioversion of persistent atrial fibrillation

We conducted a prospective randomized study to determine the safety and efficacy rate of 3 commonly used energy levels (100, 200, and 360 J) for elective direct-current cardioversion of persistent atrial fibrillation. When compared with 100 and 200 J, the initial success rate with 360 J was significantly higher (14%, 39%, and 95%, respectively), and patients randomized to 360 J ultimately required less total energy and a lower number of shocks.

Biventricular pacing decreases the inducibility of ventricular tachycardia in patients with ischemic cardiomyopathy

Biventricular pacing (BV) has been studied extensively in patients with left ventricular dysfunction. Preliminary studies have shown improvement in hemodynamics and exercise tolerance in this patient population. However, the electrophysiologic effects of BV pacing remain poorly understood. The purpose of this study was to assess the effect of BV pacing on the inducibility of sustained monomorphic ventricular tachycardia (VT) in patients with coronary artery disease. We hypothesized that acute BV pacing reduces the inducibility of sustained monomorphic VT in patients with ischemic cardiomyopathy.

Effect of Atrial Fibrillation and an Irregular Ventricular Response on Sympathetic Nerve Activity in Human Subjects

Background—Although the hemodynamic changes associated with atrial fibrillation (AF) have been extensively studied, the neural changes remain unclear. We hypothesized that AF is associated with an increase in sympathetic nerve activity (SNA) and that the irregular ventricular response contributes to this state of sympathoexcitation. Methods and Results—In 8 patients referred for an electrophysiological study, SNA, blood pressure (BP), central venous pressure (CVP), and heart rate were recorded during 3 minutes of normal sinus rhythm (NSR) and 3 minutes of induced AF. In 5 of 8 patients who converted to NSR, right atrial (RA) pacing was performed for 3 minutes in atrial pacing triggered by ventricular sensing mode triggered by playback of an FM tape previously recorded from the right ventricle during AF (RA-irregular) and atrial pacing inhibited by atrial sensing mode at a rate equal to the mean heart rate obtained during AF (RA-regular). SNA data were expressed as percentage of baseline during NSR. SNA increased in all 8 patients during induced AF compared with NSR (171±40% versus 100%, respectively;P <0.01). This was associated with a trend for a decrease in BP and an increase in CVP (P =0.02). Similarly, SNA was significantly higher during RA-irregular pacing compared with RA-regular pacing (124±24% versus 91±20%, respectively;P =0.03). BP and CVP were not significantly different between the 2 pacing modes. Conclusions—Induced AF results in a significant increase in SNA, which is in part attributable to the irregular ventricular response. Our findings suggest that restoring NSR or regularity might be beneficial, particularly in patients with heart failure.

Effects of repeated electrical defibrillations on cardiac troponin I levels

Multiple endocardial countershocks applied during intraoperative endocardial implantable cardioverter-defibrillator testing for the purpose of defibrillation threshold determination resulted in detectable myocardial injury in 5 of 12 patients, as indicated by elevations in cardiac troponin I levels. This injury was not associated with acute changes on the surface electrocardiogram.

Cardiac Arrest in Pregnancy: A Scientific Statement From the American Heart Association.

This is the first scientific statement from the American Heart Association on maternal resuscitation. This document will provide readers with up-to-date and comprehensive information, guidelines, and recommendations for all aspects of maternal resuscitation. Maternal resuscitation is an acute event that involves many subspecialties and allied health providers; this document will be relevant to all healthcare providers who are involved in resuscitation and specifically maternal resuscitation.

Effects of resynchronization therapy on sympathetic activity in patients with depressed ejection fraction and intraventricular conduction delay due to ischemic or idiopathic dilated cardiomyopathy

This study assesses the effect of biventricular pacing on sympathetic nerve activity (SNA) in patients with depressed ejection fraction and intraventricular conduction delay (IVCD). Biventricular pacing has been shown to result in hemodynamic improvement in patients with depressed ejection fraction and IVCD. The effect of biventricular pacing on SNA, however, remains unclear. A total of 15 men with a mean ejection fraction of 25 +/- 4% were enrolled. Arterial pressure, central venous pressure and SNA were recorded during 3 minutes of right atrial (RA) pacing and RA-biventricular pacing. Pacing was performed at a rate 5 to 10 beats faster than sinus rhythm, with an atrioventricular interval equal to 100 ms during RA-biventricular pacing. RA-biventricular pacing resulted in greater arterial pressures (p <0.05) than RA pacing (146 +/- 15/83 +/- 11 vs 141 +/- 15/80 +/- 10 mm Hg). There were no differences in central venous pressures between the 2 pacing modes (p = 0.76). SNA was significantly less during RA-biventricular pacing (727 +/- 242 U) than during RA pacing (833 +/- 332 U) (p <0.02). Furthermore, there was a positive correlation between baseline QRS duration and the decrease in SNA noted with RA-biventricular pacing (r = 0.58, p = 0.03). Biventricular pacing results in improved hemodynamics and a decrease in SNA compared with intrinsic conduction in patients with left ventricular dysfunction and IVCD. If the current findings are also present with chronic biventricular pacing, then this form of therapy may have a positive impact on mortality.

Antiarrhythmic drugs in pregnancy.

During pregnancy a number of rhythm disturbances can occur in both the mother and fetus; these may range from benign ectopy to life-threatening arrhythmias. With a clear understanding of the maternal hemodynamic changes associated with pregnancy, and the appropriate antiarrhythmic therapies available, almost all such cases can be treated successfully. Although no drug is completely safe, most are well tolerated and can be given with relatively low risk. Drug therapy should be avoided during the first trimester of pregnancy if possible and drugs with the longest record of safety should be used as first-line therapy. Conservative therapies should be used when appropriate. Several drug options exist for most maternal and fetal arrhythmias.