Search

Background: Echocardiographically recognized resting function, myocardial viability (by low-dose dobutamine) and stress-induced ischemia (by high-dose dipyridamole) are potent predictors of subsequent events, but their relative value in patients evaluated very early after acute myocardial infarction remains to be established., Aim of the Study: To assess the feasibility and usefulness of an integrated approach with resting and pharmacological stress echo for risk stratification in patients evaluated very early after myocardial infarction., Methods: Sixty acute myocardial infarction patients without contraindications to stress testing, and who were being given thrombolytic therapy, underwent resting echo (16-segment model of left ventricle, each segment scored from 1 = normo-hyperkinetic to 4 = dyskinetic), high-dose dipyridamole (up to 0.84 mg/kg over 10') and low-dose dobutamine (up to 10 mcg/kg/min) echo on the third-fourth day after drug withdrawal. The response was "ischemic" with a dipyridamole-induced increase in the regional score > 1 in segments with a resting score < 3, and "viable" with a dobutamine-induced decrease in the regional score > 1 in segments with resting score > 1. All patients underwent coronary angiography on the tenth-twelfth day after the acute event, and all of them were followed up for 15 +/- 10.04 months., Results: Ischemia elicited by dipyridamole appeared in 29 patients (48%) and dobutamine-induced viability was observed in 28 (47%). Ischemic events occurred in 26 patients (43.4%), five of which during the early in-hospital period. There were three deaths (5%), one re-AMI (1.7%), 7 Canadian Class III-IV angina (12%) and 15 (25%) early revascularization procedures undertaken independently of stress echo results. Events occurred in 21 patients (72%) with dipyridamole-induced ischemia and in 5 (16%) without it (p < 0.001). Likewise, events occurred in 13 patients (46.4%) with dobutamine-induced inotropic recovery and in 13 (40.6%) without it (p = ns). Event-free survival occurred in 64% of dipyridamole-positive patients, as opposed to 90% of dipyridamole-negative patients (p = 0.025). Dipyridamole echocardiographic test sensitivity and specificity for events were 81 and 74%, respectively. Sensitivity and specificity for events of dobutamine viability were 46 and 55%, respectively. In a multivariate logistic analysis, dipyridamole-induced myocardial ischemia was the strongest predictor of subsequent events (p = 0.01). According to Cox analysis, dipyridamole positivity had a relative risk estimate of 4., Conclusions: Pharmacological stress echo is feasible even very early after acute myocardial infarction via a useful approach based on low-dose dobutamine to assess myocardial viability, and high-dose dipyridamole to assess ischemia. For risk stratification purposes, stress-induced myocardial ischemia outperforms resting function and myocardial viability, and it is independent of angiographic data. Revascularization procedures do not seem to be effective when only viability is present.

Background: Several weeks of prophylactic anticoagulation are routinely prescribed before and after electrical cardioversion of atrial fibrillation. Recent studies have supported the use of transesophageal echocardiography to guide early cardioversion: patients in whom no thrombus is observed are treated with heparin followed by one month of warfarin therapy after the procedure. This kind of treatment requires hospital admission during heparin infusion, because of the need for monitoring partial thromboplastin time., Aim of the Study: To evaluate if a short at-home treatment (three days) with warfarin is sufficient to reach a good level of anticoagulation, in order to permit safe electrical cardioversion in day-hospital for patients who show no thrombi on transesophageal echocardiography., Methods: One hundred twenty-four patients with atrial fibrillation, who were candidates for cardioversion, were treated with warfarin: 10 mg the first and second day, 5 mg the third day in group A patients (n = 79); 15 mg the first day, 10 mg the second and third day in group B patients (n = 45). On the fourth day, INR value was measured and if it was < 2, warfarin therapy was prolonged until patients reached a good level of anticoagulation. Transesophageal echocardiography was performed when the INR was > or = 2, and patients were cardioverted with DC shock if there were no thrombi. The patients were discharged on the same day of the procedure, and warfarin therapy was continued for 4 weeks there-after. If a thrombus was detected, patients repeated transesophageal echocardiography after 6 weeks of warfarin therapy, and were cardioverted if the thrombus disappeared. Otherwise, cardioversion was deferred and they received prolonged warfarin treatment. If there was poor visualization of the left atrial appendage, patients received conventional warfarin therapy for 3 weeks before and 4 weeks after electrical cardioversion., Results: Mean INR value after three days of warfarin treatment was 2.41 in group A patients and 3.02 in group B patients. Twenty-one patients from group A and 3 patients from group B required anticoagulant therapy for a mean of 3.3 and 5.1 days, respectively, before reaching a good level of anticoagulation (INR value > or = 2). Eight patients reverted spontaneously to sinus rhythm before transesophageal echocardiography. Eighteen thrombi (15.5%) were identified on the transesophageal echocardiography, all of which were in the left atrial appendage. In 11 cases, thrombus disappeared after 6 weeks of warfarin therapy. In 7 patients (6%), the atrial appendage was not sufficiently visualized. Electrical cardioversion was performed on 109 patients and was successful in 88 (80.7%). None of them experienced a clinical thromboembolic event., Conclusions: In the majority of patients in atrial fibrillation, a short at-home warfarin treatment is sufficient to reach a good level of anticoagulation in order to permit safe electrical cardioversion in a day-hospital situation. Larger initial doses can achieve even better results. This treatment algorithm minimizes the anticoagulation period, hospital stay, overall duration of atrial fibrillation and the time required for the mechanical function of the left atrium to return.

Background: Thromboembolic complications after electrical cardioversion (CV) of atrial fibrillation (AF) have been attributed to the dislodgment of preexistent left atrial thrombus during the resumption of atrial contraction. Transesophageal echocardiography (TEE) has been used to identify patients without thrombus, who potentially could undergo CV without anticoagulation. However, embolic events after CV in patients without evidence of thrombus on TEE have recently been reported., Aim of the Study: To evaluate if absence of thrombi or prethrombotic conditions such as spontaneous echo contrast or left atrial appendage disfunction can justify electrical CV without anticoagulant therapy., Methods: Seventy-four patients with AF and candidates for CV underwent monoplane TEE. Patients were cardioverted without anticoagulation in case of: 1) absence of thrombus and/or spontaneous echocardiographic contrast and 2) good visualization of left atrial appendage, with a well defined peak blood flow velocity greater than 20 cm/sec. In all other cases, patients underwent anticoagulant therapy which started 3 weeks before CV and continued for 4 weeks afterwards., Results: Forty-six patients, without thrombus or "prethrombotic" conditions, did not receive anticoagulation, while 28 followed traditional therapy with warfarin. Four patients with a thrombus in the left atrial appendage were identified: 1 died of cerebral embolism 3 days after the beginning of anticoagulation, in another one CV was definitely deferred because of the persistence of thrombus after 1 month of warfarin therapy. One patient, with left atrial appendage disfunction, died suddenly after 5 days of anticoagulation. Two patients reverted spontaneously in sinus rhythm. Two patients refused electrical CV. The remaining 67 patients underwent electrical CV which was successful in 56 of them. Cerebral embolism occurred 24 hours after CV in one patient who did not receive anticoagulation. Repeat TEE soon after embolism showed absence of thrombus or spontaneous echo contrast, but the presence of low flow velocity in the left atrial appendage., Conclusions: In patients in AF candidates for CV, exclusion of thrombi or prethrombotic conditions by TEE does not exclude the risk of thromboembolic events and the need for anticoagulant therapy. Left atrial appendage function can be stunned or impaired immediately after CV, favouring a thrombogenic milieu and subsequent embolic events. Therapeutic anticoagulation at the time of as well as after cardioversion is actually recommended.