Krishnakant Nammi

Waveform Analysis–Guided Treatment Versus a Standard Shock-First Protocol for the Treatment of Out-of-Hospital Cardiac Arrest Presenting in Ventricular Fibrillation Results of an International Randomized, Controlled Trial

Background— Ventricular fibrillation (VF) waveform properties have been shown to predict defibrillation success and outcomes among patients treated with immediate defibrillation. We postulated that a waveform analysis algorithm could be used to identify VF unlikely to respond to immediate defibrillation, allowing selective initial treatment with cardiopulmonary resuscitation in an effort to improve overall survival. Methods and Results— In a multicenter, double-blind, randomized study, out-of-hospital cardiac arrest patients in 2 urban emergency medical services systems were treated with automated external defibrillators using either a VF waveform analysis algorithm or the standard shock-first protocol. The VF waveform analysis used a predefined threshold value below which return of spontaneous circulation (ROSC) was unlikely with immediate defibrillation, allowing selective treatment with a 2-minute interval of cardiopulmonary resuscitation before initial defibrillation. The primary end point was survival to hospital discharge. Secondary end points included ROSC, sustained ROSC, and survival to hospital admission. Of 6738 patients enrolled, 987 patients with VF of primary cardiac origin were included in the primary analysis. No immediate or long-term survival benefit was noted for either treatment algorithm (ROSC, 42.5% versus 41.2%, P=0.70; sustained ROSC, 32.4% versus 33.4%, P=0.79; survival to admission, 34.1% versus 36.4%, P=0.46; survival to hospital discharge, 15.6% versus 17.2%, P=0.55, respectively). Conclusions— Use of a waveform analysis algorithm to guide the initial treatment of out-of-hospital cardiac arrest patients presenting in VF did not improve overall survival compared with a standard shock-first protocol. Further study is recommended to examine the role of waveform analysis for the guided management of VF. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00535106.

A user-friendly integrated monitor-adhesive patch for long-term ambulatory electrocardiogram monitoring.

BACKGROUND Compliance to long-term ambulatory electrocardiogram monitoring is important for diagnosis in patients with cardiac arrhythmia. This requires a system with a minimal impact on daily activities. OBJECTIVE The aim of this study was to investigate if a lightweight integrated adhesive monitor for long-term use without unacceptable adverse effects is feasible. METHODS The participants wore either a prototype lightweight monitor or a control system for a total of up to 30 days, changing patches once (investigational device) or twice (control) weekly. Comfort, skin irritation, and impact on quality of life were recorded. RESULTS The new monitor can be worn by most participants for periods of at least 6 days. Skin irritation and comfort rating were comparable, and impact on the quality of life was low compared with the control. Patients considered the device comfortable. CONCLUSION An integrated adhesive monitor that can be worn on the skin up to 7 days with minimal side effects is feasible.

Detection of ventricular ectopy by a novel miniature electrocardiogram recorder

BACKGROUND The ability of a miniaturized, skin-attached, 3-channel electrocardiogram (ECG) recorder prototype to detect ventricular ectopic beats (VEBs) and ventricular fibrillation (VF) was compared with that of standard Holter ECG. METHODS Concurrent 15-hour ECG recordings were made in 143 patients using an experimental device provided by Philips Healthcare (Seattle, WA) and a commercially available Holter recorder. In a consensus review process, 3 physicians (M.L., A.J., and A.G.), blinded for the recording device, analyzed 1804 seven-second strips for total number of VEBs, total number of their QRS configurations, and presence of VF. Agreement between the experimental and standard devices was calculated using Spearman correlation coefficients. RESULTS There was 100% agreement regarding VF recognition. Spearman correlation coefficients were 0.98 (P < .001) for the total number of VEBs and 0.91 (P < .001) for the total number of QRS configurations. CONCLUSIONS The accuracy of the experimental miniaturized ECG recorder for detecting ventricular activity was found to be high. This finding could be of clinical importance.

Towards an algorithm for automatic accelerometer-based pulse presence detection during cardiopulmonary resuscitation

Manual palpation is still the gold standard for assessment of pulse presence during cardiopulmonary resuscitation (CPR) for professional rescuers. However, this method is unreliable, time-consuming and subjective. Therefore, reliable, quick and objectified assessment of pulse presence in cardiac arrest situations to assist professional rescuers is still an unmet need. Accelerometers may present a promising sensor modality as pulse palpation technology for which pulse detection at the carotid artery has been demonstrated to be feasible. This study extends previous work by presenting an algorithm for automatic, accelerometer-based pulse presence detection at the carotid site during CPR. We show that accelerometers might be helpful in automated detection of pulse presence during CPR.

Response to Letter Regarding Article, “Waveform Analysis–Guided Treatment Versus a Standard Shock-First Protocol for the Treatment of Out-of-Hospital Cardiac Arrest Presenting in Ventricular Fibrillation: Results of an International Randomized, Controlled Trial”

We appreciate the correspondence from Drs Ristagno and Li. We also thank them and their colleagues for their many contributions to the resuscitation literature and for the most recent in their series of work on the use of amplitude spectrum area both for the prediction of defibrillation success and as a surrogate marker for cardiopulmonary resuscitation (CPR) quality. Ventricular fibrillation (VF) has long been viewed as a ubiquitous condition best treated with immediate defibrillation, yet the evolution of our understanding of this lethal arrhythmia, the optimal timing for defibrillatory shocks, and the interaction between CPR quality and changes in the VF waveform has only recently begun to flourish. The threshold value chosen for our study1 did, as the authors of the letter suggest, have …