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Background: The huge importance of rapid provision of care, especially early defibrillation, for survival of out-of-hospital cardiac arrest (OHCA) is well known. This prospective cohort study investigated cognitive functioning of OHCA survivors in relation to the time-related elements of the resuscitation., Methods: Fifty-seven consecutive survivors, from a cohort of 308 witnessed OHCA patients with ventricular fibrillation as the initial rhythm, underwent extensive neuropsychologic examination, including tests of memory, attention, and executive functioning, 6 months after the resuscitation. Time-related aspects of the resuscitation were collected on scene. Cognitive functioning was studied in relation to the administration of cardiopulmonary resuscitation (CPR) prior to ambulance arrival, and time from collapse to start of CPR, defibrillation, and return of spontaneous circulation (ROSC)., Results: Depending of the test, between 11% and 28% of survivors were cognitively impaired, while 58% scored unimpaired for all tests. Daily life activities were limited in 19% of the patients. Patients who received CPR prior to arrival of the ambulance showed a trend towards overall better cognitive functioning and significant better immediate memory and visuomotor tracking (P =.03 and P <.01). We found a weak correlation between the time to CPR, time to defibrillation, or time to ROSC and cognitive functioning., Conclusions: The majority of survivors of OHCA with ventricular fibrillation as the initial rhythm are cognitively unimpaired. Long delays to ROSC are compatible with good cognitive outcome. Initiation and cessation of resuscitation efforts should not be based on the duration of circulatory arrest.

Background: We compared efficacy of and pain felt after biphasic truncated exponential (BTE) and monophasic damped sine (MDS) shocks in patients undergoing external cardioversion of atrial fibrillation (AF)., Methods: Patients with AF were randomized to BTE or MDS waveform cardioversion. Successive shocks were delivered at 70, 100, 200, and 360 J until successful cardioversion, with one 360 J attempt of the alternate waveform when all 4 shocks failed. Success was determined by blinded over-read of electrocardiograms. Peak current was calculated from energy and impedance. Patients rated their pain at 1 and 24 hours after cardioversion., Results: Fourteen of 37 (38%) patients treated with MDS and 34 of 35 (97%) treated with BTE shocks were cardioverted at < or =200 J (P <.0001). Success rates of MDS versus BTE shocks were 5.4% versus 60% for 70 J, 19% versus 80% for < or =100 J, and 86% versus 97% for < or =360 J. BTE shocks cardioverted with less peak current (14.0 +/- 4.3 vs 39.5 +/- 11.2 A, P <.0001), less energy (97 +/- 47 vs 278 +/- 120 J, P <.0001), and less cumulative energy (146 +/- 116 vs 546 +/- 265 J, P <.0001). Patients felt less pain after BTE than MDS shocks at 1 hour (P <.0001) and 24 hours (P <.0001) after cardioversion., Conclusion: This BTE waveform is superior to the MDS waveform for cardioversion of AF, requiring much less energy and current, and causing less postprocedural pain.

Study Objective: The protocol for the use of the automated external defibrillator calls for a period of "hands-off" time, during which no cardiopulmonary resuscitation (CPR) can be performed. We assessed the actual interruption time of CPR during the use of the automated external defibrillator in patients in out-of-hospital cardiac arrest., Methods: This study included 184 patients experiencing out-of-hospital cardiac arrest in which an automated external defibrillator was applied by first responders. ECG and voice recordings from the automated external defibrillator were downloaded and analyzed. Start and end times of CPR were recorded, as were intervals measured from the recordings concerning the programmed interruption time and the interruption time related to performance., Results: The automated external defibrillators were connected for a median time of 4 minutes 47 seconds (range 31 to 1,404 seconds). CPR was performed during 45%+/-15% (mean+/-SD) of the connected time or until return of spontaneous circulation. During the automated external defibrillator connection time in the 96 patients with a shockable rhythm, CPR was performed 36%+/-20% of the time. Programmed interruption of CPR took 40%+/-15% of the automated external defibrillator connection time, and no CPR was performed related to performance during 23%+/-15% of the time. A palpable pulse was never present immediately after a shock, and return of spontaneous circulation was observed in 3 of 184 patients before arrival of the ambulance. Ultimately, return of spontaneous circulation occurred in 87 of 184 patients., Conclusion: First responders using automated external defibrillator voice prompts provide CPR less than half the time that the automated external defibrillator is connected to the patient. Technical improvements in automated external defibrillator rhythm analysis, more efficient resuscitation algorithms, and first-responder education could increase CPR delivery and, perhaps, improve outcome.

Study Objective: We evaluated the diagnostic accuracy of myoglobin determination for the early diagnosis of acute myocardial infarction (AMI)., Methods: Consecutive patients with chest pain were included in the study. Receiver operating characteristic (ROC) analysis was used to assess optimal timing of blood sampling and cutoff values., Results: A total of 309 patients were included, of whom 162 patients had a diagnosis of AMI. ROC analysis revealed that the diagnostic accuracy of myoglobin concentration as indicated by the area under the ROC curve (AUC) increased significantly from 3 (0.89+/-0.026) and 4 hours (0.93+/-0.019) to 5 hours after onset of symptoms (0. 96+/-0.014; P=.0040 and.035, respectively). At 5 hours (the earliest time point with maximal AUC), sensitivity was 87% and specificity was 97% using a myoglobin cutoff value of 90 microg/L. With a myoglobin cutoff value of 50 microg/L, sensitivity was 95% (95% confidence interval 90% to 98%), but specificity was 86% (95% confidence interval 80% to 93%)., Conclusion: Myoglobin has maximal diagnostic accuracy for the diagnosis of AMI at 5 hours after the onset of symptoms, using a cutoff value of 50 microg/L. In combination with the measurement of other biochemical markers, myoglobin determination could be particularly useful for triage of patients with AMI at an early stage.

The pathogenesis of mitral regurgitation (MR) was determined by quantitative echocardiography in 188 patients with acute myocardial infarction (AMI) within 48 hours after admission. MR was classified, by using color Doppler, as significant (grades 3 to 4) or trivial (grades 0 to 2). Left ventricular (LV) function (global and regional), volume, and shape, as well as mitral valvular features, were measured and analyzed by stepwise logistic regression. Significant MR occurred in 25 (13%) patients. Univariately, recurrent infarction (p < 0.01), LV dilation (p < 0.001) and sphericity (p < 0.001), inferoposterolateral asynergy (p < 0.001), mitral annular dilatation (p < 0.005), and mitral leaflet restriction (p < 0.05) were associated with significant MR. In regression analysis, only recurrent infarction (odds ratio 5.08), LV sphericity index (odds ratio 1.12), and inferoposterolateral asynergy (odds ratio 6.07) were independently associated with significant MR, whereas none of the mitral valvular features examined had an independent association. In conclusion, changes in LV shape and regional function and not mitral valvular changes are prime determinants of significant MR after AMI.