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. Other clinical findings and tolerability. The MIAMI Trial Research Group.
Fifteen minutes after injection there was a fall in mean heart rate (18%, p less than 0.001), systolic blood pressure (10%, p less than 0.001) and rate-pressure product (27%, p less than 0.0001) in the metoprolol group of patients in the MIAMI trial. Hypotension and bradycardia not necessarily associated with withdrawal of drug were more common in the metoprolol group (p less than 0.001). Atrioventricular block I was more common in the metoprolol group (p less than 0.03), whereas no such difference was observed for atrioventricular block II and III, asystole or pacemaker implantations. ⋯ The trial medication was withdrawn temporarily more often in the metoprolol than in the placebo group (p less than 0.001). However, permanent withdrawal of trial medication occurred with a similar frequency overall in both groups. More patients were withdrawn from the study because of cardiovascular reasons in the metoprolol group (9%) than in the placebo group (5%, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)