Cost-effectiveness of cardioversion and antiarrhythmic therapy in nonvalvular atrial fibrillation.

BACKGROUND: Physicians managing patients with nonvalvular atrial fibrillation must consider the risks, benefits, and costs of treatments designed to restore and maintain sinus rhythm compared with those of rate control with antithrombotic prophylaxis. OBJECTIVE: To compare the cost-effectiveness of cardioversion, with or without antiarrhythmic agents, with that of rate control plus warfarin or aspirin. DESIGN: A Markov decision-analytic model was designed to simulate long-term health and economic outcomes. DATA SOURCES: Published literature and hospital accounting information. TARGET POPULATION: Hypothetical cohort of 70-year-old patients with different baseline risks for stroke. TIME HORIZON: 3 months. PERSPECTIVE: Societal. INTERVENTION: Therapeutic strategies using different combinations of cardioversion alone, cardioversion plus amiodarone or quinidine therapy, and rate control with antithrombotic treatment. OUTCOME MEASURES: Expected costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness. RESULTS OF BASE-CASE ANALYSIS: Strategies involving cardioversion alone were more effective and less costly than those not involving this option. For patients at high risk for ischemic stroke (5.3% per year), cardioversion alone followed by repeated cardioversion plus amiodarone therapy on relapse was most cost-effective ($9300 per QALY) compared with cardioversion alone followed by warfarin therapy on relapse. This strategy was also preferred for the moderate-risk cohort (3.6% per year), but the benefit was more expensive ($18,900 per QALY). In the lowest-risk cohort (1.6% per year), cardioversion alone followed by aspirin therapy on relapse was optimal. RESULTS OF SENSITIVITY ANALYSIS: The choice of optimal strategy and incremental cost-effectiveness was substantially influenced by the baseline risk for stroke, rate of stroke in sinus rhythm, efficacy of warfarin, and costs and utilities for long-term warfarin and amiodarone therapy. CONCLUSIONS: Cardioversion alone should be the initial management strategy for persistent nonvalvular atrial fibrillation. On relapse of arrhythmia, repeated cardioversion plus low-dose amiodarone is cost-effective for patients at moderate to high risk for ischemic stroke.

Critical pathway management of unstable angina.

The critical pathway for UA is a multidisciplinary management tool designed to assist in expediting the treatment and evaluation of this frequent clinical syndrome. No critical pathway or practice guideline will meet the needs of all patients, and flexibility for patient variations and physician judgment is mandatory. Prediction tools and other facilitators cannot replace and must not impede the thoughtful assessment of complex clinical situations. Numerous factors, occasionally social or political in nature, impact on patient treatment strategies and the application of interventions. It is our hope that the Unstable Angina Critical Pathway will form a foundation for further innovation and cooperative effort toward optimizing the management of patients with acute ischemic syndromes.

Double-lumen catheter assessment of aortic stenosis: comparison with separate catheter technique.

Hemodynamic assessment of aortic stenosis in the catheterization laboratory accurate determination of the transvalvular gradient. A commercially available double-lumen pigtail catheter can be used to obtain this gradient via a single arterial puncture. The catheter has several advantages over other methods used to measure the gradient in aortic stenosis, but it has not been critically evaluated. In order to assess the performance of this catheter compared to the traditional standard of separate catheters above and across the aortic valve, we studied 10 patients with aortic stenosis using both catheter systems. Aortic valve areas ranged from 0.34 cm2 to 1.1 cm2. Linear regression analysis confirmed excellent correlation between the two methods in measurement of the mean transvalvular gradient (r = 0.98) and calculation of the aortic valve area (r = 0.99) using the Gorlin formula. We conclude that the double-lumen pigtail catheter provides accurate data in the hemodynamic evaluation of aortic stenosis.

Two-dimensional echocardiographic recognition of left ventricular pseudoaneurysm.

Five consecutive patients with proved left ventricular pseudoaneurysm (PA) and 22 patients with true aneurysm (TA) were studied by two-dimensional echocardiography (2DE). In four of the five patients with PA, 2DE successfully displayed the PA. The unique 2DE characteristics of PA include: (1) a sharp discontinuity of the endocardial image at the site of the PA communication with the left ventricular cavity; (2) a saccular or globular contour of the PA chamber; and (3) the presence of a relatively narrow orifice in comparison with the diameter of the PA fundus. In addition, 2DE detected the presence of thrombotic material within the extraventricular chamber in three of four cases. By deriving the ratios of the end-systolic orifice to diameter measurements for the patients with PA (0.37 +/- 0.07) compared with TA (1.00 +/- 0.08), we found that 2DE reliably differentiated PA from TA (p < 0.001). We conclude that 2DE is a useful noninvasive method for revealing left ventricular PAs and for distinguishing PA from TA. Considering the high risk of spontaneous rupture associated with pseudoaneurysms, this noninvasive capability is of paramount clinical importance.

Pseudoaneurysm of the left ventricle complicated by Salmonella typhimurium infection. Recognition by two-dimensional echocardiography.

A patient is described with a large posterior left ventricular pseudoaneurysm complicated by Salmonella typhimurium infection. M-mode echocardiography displayed a massive echo-free space behind the posterior left ventricular wall, and two-dimensional echocardiography specifically defined the orifice and saccular contour of the false aneurysm. These findings were confirmed by cardiac catheterization and surgery. The unusual features of Salmonella endovascular infection and the noninvasive methods to detect left ventricular pseudoaneurysms are reviewed.

Myocardial bridging of the left anterior descending artery: evaluation using exercise thallium-201 myocardial scintigraphy.

Seven patients with myocardial bridging of the left anterior descending coronary artery were evaluated by mens of thallium-201 exercise scintigraphy. The degree of systolic narrowing was 60-70% in five patients and 75-80% in two patients. All patients had presented with chest pain. The resting electrocardiogram was normal in six patients; there were ST segment and T-wave abnormalities in one patient. No patient complained of chest pain during exercise. The exercise electrocardiogram was negative in six patients and inconclusive in one patient. Exercise myocardial scans were negative in all seven patients. We conclude that no evidence of ischemia was demonstrated in patients with myocardial bridging of the left anterior descending coronary artery as determined by exercise electrocardiography and stress thallium-201 scintigraphy.

Dislodgment of pacemaker electrode simulating focal motor seizure.

The unusual finding of dislocation of the electrode of a pacemaker in a patient caused repetitive twitching of the right leg. Initial confusion with focal motor seizure resulted in the administration of antiepileptic medication. Malposition of the electrode was confirmed by appropriate roentgenographic studies, and subsequent repositioning terminated the episode.