The American journal of cardiology
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Two hundred sixty patients in cardiac arrest were treated with an automatic external defibrillator by first-responding firefighters before arrival of paramedics. On average, first responders arrived 5 minutes before paramedics. Of 118 patients with ventricular fibrillation, 91 (77%) were administered shocks, 21 (23%) of whom had return of pulse and blood pressure by the time paramedics arrived. ⋯ The survival rate for all 118 victims discovered with ventricular fibrillation was 27%. The device correctly classified the initial and all subsequent rhythms in 92 patients with asystole, 46 with electromechanical dissociation, and 22 others with presumed respiratory arrest; it did not deliver any inappropriate shocks to patients or to the rescuers using the device. An automatic external defibrillator can be used by first responders as an adjunct to basic life support, and its use may improve survival by shortening the time to defibrillation.
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Comparative Study
Usefulness of right ventricular diastolic collapse in diagnosing cardiac tamponade and comparison to pulsus paradoxus.
To compare the sensitivity, specificity and predictive value of right ventricular (RV) diastolic collapse and pulsus paradoxus as signs of cardiac tamponade, 21 consecutive patients with pericardial effusion and suspected cardiac tamponade underwent prospective hemodynamic and echocardiographic evaluation. Simultaneous hemodynamic and echocardiographic data were obtained in all patients before and after pericardiocentesis. ⋯ The positive and negative predictive values of RV diastolic collapse (100% and 83%) were considerably better than pulsus paradoxus (81% and 40%) and demonstrate that RV diastolic collapse is more sensitive, specific and predictive of cardiac tamponade than is pulsus paradoxus. Serial simultaneous hemodynamic and echocardiographic observations at multiple points during pericardiocentesis in a smaller subgroup (5 patients) also suggest that the hemodynamic effects of RV diastolic collapse in cardiac tamponade are mediated by an increase in intrapericardial pressure.
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Randomized Controlled Trial Clinical Trial
Metoprolol in acute myocardial infarction. Patients and methods. The MIAMI Trial Research Group.
The effects of early intervention with metoprolol in patients with suspected or definite acute myocardial infarction (AMI) have been assessed in a randomized, double-blind, placebo-controlled international study. Patients aged 75 years or younger were eligible for entry if they presented to a coronary care unit within 24 hours of the onset of symptoms of an AMI. Exclusion criteria included current treatment with a beta blocker or calcium-channel blocker, heart rate less than or equal to 65 beats/min, systolic blood pressure less than or equal to 105 mm Hg, contraindications and other administrative reasons. ⋯ The study period was 15 days in addition to the day of randomization. The patients' clinical history and status at entry were documented. The following outcome variables were recorded: mortality, development of AMI, serum enzyme activity, electrocardiographic signs of AMI, late or recurrent AMI, arrhythmias, treatment of chest pain, concomitant treatment, adverse events and details of treatment with trial medication.
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Randomized Controlled Trial Clinical Trial
Metoprolol in acute myocardial infarction. Mortality. The MIAMI Trial Research Group.
After 15 days there were 142 deaths in the placebo group (4.9%) and 123 deaths in the metoprolol group (4.3%), a difference of 13% (p = 0.29). The 95% confidence limits for the relative effect of metoprolol ranged from an 8% excess (-8%) to a 33% reduction (+33%) in mortality. There was generally a lower mortality rate for metoprolol-treated patients in most subgroups and a consistent tendency for a more pronounced difference between the treatment groups in those subgroups with a placebo mortality rate higher than the average for all placebo patients. ⋯ Using a simple model, the placebo mortality was found to increase with increasing number of 8 risk predictors defined from prestudy experience, from 0% in patients with no risk predictors to 11.6% in patients with any 5 or more of these risk factors. Similarly, there was an increase in the difference between the treatment groups in favor of metoprolol with increasing number of placebo risk factors. Metoprolol had no apparent effect in a low-mortality risk group (less than or equal to 2 risk factors), but there was a difference in mortality of 29% in favor of metoprolol in a high-risk group (greater than or equal to 3 risk factors) comprising one-third of the trial population.(ABSTRACT TRUNCATED AT 250 WORDS)