Journal of the American College of Cardiology
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J. Am. Coll. Cardiol. · Feb 1994
Randomized Controlled Trial Clinical TrialCombination biphasic waveform plus sequential pulse defibrillation improves defibrillation efficacy of a nonthoracotomy lead system.
We hypothesized that combining biphasic waveform and sequential pulse defibrillation techniques would lower the defibrillation threshold of a nonthoracotomy lead system in humans below that obtained with biphasic or sequential pulse defibrillation alone. ⋯ Adding biphasic waveform to sequential pulse defibrillation significantly reduced the defibrillation threshold compared with either technique alone, and nonthoracotomy lead system implantation can be enhanced by this combined technique.
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J. Am. Coll. Cardiol. · Feb 1994
Feasibility of generating hemodynamic pressure curves from noninvasive Doppler echocardiographic signals.
This study was designed to determine the feasibility of Doppler generation of accurate, complete right ventricular and pulmonary artery pressure curves in patients with Doppler-measurable tricuspid and pulmonary regurgitation. ⋯ Clinically usable right ventricular and pulmonary artery pressure curves can be derived by superimposing Doppler-measured tricuspid and pulmonary valve blood flow velocities in patients with tricuspid and pulmonary valve regurgitation.
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J. Am. Coll. Cardiol. · Feb 1994
ReviewShould all patients undergo transesophageal echocardiography before electrical cardioversion of atrial fibrillation?
The management of anticoagulant therapy in patients with atrial fibrillation undergoing electrical cardioversion remains controversial, largely because of inadequate studies demonstrating risk or benefit, a relatively inconvenient anticoagulation management strategy and the increasing use of transesophageal echocardiography. Recent investigations into the potential mechanisms involved in the development of thrombus and systemic embolism in patients undergoing electrical cardioversion of atrial fibrillation may provide insight into underlying predisposing factors, with subsequent modification of management strategies. Conventional wisdom suggests that preexisting thrombus is responsible for thromboembolic events after cardioversion. ⋯ To protect against both potential mechanisms of embolization, these data support therapeutic anticoagulation for all patients with atrial fibrillation of > 2 days in duration from the time of, as well as after cardioversion for a total of 4 weeks, undergoing cardioversion, even in the absence of thrombus on echocardiography. Therefore, the role of transesophageal echocardiography in this setting should be to enable early cardioversion if atrial thrombus is excluded and to identify high risk patients with atrial thrombi so as to postpone cardioversion and avoid the risk of embolization. Ultimately, however, a controlled, randomized and prospective clinical trial will be required to compare conventional management with a transesophageal echocardiography-guided strategy.
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J. Am. Coll. Cardiol. · Feb 1994
Transesophageal echocardiography before and during direct current cardioversion of atrial fibrillation: evidence for "atrial stunning" as a mechanism of thromboembolic complications.
The purpose of this study was to evaluate the usefulness of transesophageal echocardiography before electrical cardioversion in patients with atrial fibrillation and to determine the mechanism of thromboembolism after cardioversion. ⋯ Transesophageal echocardiographic detection of left atrial thrombus before direct current cardioversion is important but infrequent in patients with predominantly nonvalvular atrial fibrillation. The occurrence of thromboembolic complications in the absence of demonstrable left atrial thrombus and the new development of spontaneous echo contrast in association with the transient atrial dysfunction ("stunning") caused by cardioversion suggest that cardioversion may promote new thrombus formation, in which case all patients should receive full anticoagulant therapy at the time of cardioversion.
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J. Am. Coll. Cardiol. · Feb 1994
Clinical TrialA new dosing regimen for esmolol to treat supraventricular tachyarrhythmia in Chinese patients.
The purpose of this study was to find a safe dosing regimen for esmolol infusion to rapidly control supraventricular tachyarrhythmia after cardiac surgery in Chinese patients. ⋯ The dosing regimen for esmolol infusion recommended in western studies is not suitable for Chinese patients. In this report we propose a new dosing regimen for esmolol infusion that is both safe and rapid in the treatment of supraventricular tachyarrhythmia in Chinese patients.