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Biomedical subjects

D I Silverman

Publications and source records attributed to D I Silverman.

At least 19 recordsLinked to original sources
PubMed2001

Early cardioversion of atrial fibrillation facilitated by transesophageal echocardiography: short-term safety and impact on maintenance of sinus rhythm at 1 year.

BACKGROUND: For patients presenting with atrial fibrillation of only a few weeks duration, the use of transesophageal echocardiography offers the opportunity to markedly abbreviate the duration of atrial fibrillation before cardioversion. We sought to determine if the shorter duration of atrial fibrillation allowed by a transesophageal echocardiography strategy had an impact on the recurrence of atrial fibrillation and prevalence of sinus rhythm during the first year following cardioversion. METHODS: Transesophageal echocardiography was attempted in 539 patients (292 men, 247 women; 71.6 +/- 13.0 years.) with atrial fibrillation > or =2 days (66.1% <3 weeks) or of unknown duration before elective cardioversion of atrial fibrillation. Therapeutic anticoagulation at the time of transesophageal echocardiography was present in 94.6% of patients, and 73.4% of subjects were discharged on warfarin. RESULTS: Atrial thrombi were identified in 70 (13.1%) patients. Successful cardioversion in 413 patients without evidence of atrial thrombi was associated with clinical thromboembolism in 1 patient (0.24%, 95% confidence interval: 0.0--0.8%). In patients with atrial fibrillation <3 weeks at the time of cardioversion (a duration incompatible with conventional therapy of 3 to 4 weeks of warfarin before cardioversion), the 1-year atrial fibrillation recurrence rate was lower (41.1% vs. 57.9%, P <0.01), and the prevalence of sinus rhythm at 1 year was increased (65.8% vs. 51.3%, P <0.03). No other clinical or echocardiographic index was associated with recurrence of atrial fibrillation or sinus rhythm at 1 year. CONCLUSIONS: Early cardioversion facilitated by transesophageal echocardiography has a favorable safety profile and provides the associated benefit of reduced recurrence of atrial fibrillation for patients in whom the duration of atrial fibrillation is <3 weeks.

Adult↗
PubMed2001

Predictors of conversion of atrial fibrillation after cardiac operation in the absence of class I or III antiarrhythmic medications.

BACKGROUND: Although risk factors for the development of atrial fibrillation (AF) after cardiac operations have been studied extensively, predictors of conversion to sinus rhythm within 24 hours of onset have not been examined. METHODS: Eleven hundred consecutive adults undergoing cardiovascular operations from July 1997 to June 1998 were screened for new onset AF after operation. Patients with chronic persistent preoperative AF or those who died within 48 hours of the operation were excluded. RESULTS: Three hundred fifty-three patients develop

Adrenergic beta-Antagonists↗
PubMed1999

The genetic basis of aortic disease. Marfan syndrome and beyond.

The Marfan syndrome and related disorders are systemic disorders of connective tissue. Proximal aorta is usually dilated. The molecular basis of Marfan syndrome has been elucidated, thus allowing prenatal diagnosis. Life expectancy has markedly improved due to the widespread use of beta-adrenergic receptor inhibitors and improved surgical management of the aortic disease.

Aortic Aneurysm↗
PubMed1999

Interval-force relation is unaffected by the presence of cardiomyopathy or coronary artery disease in patients with atrial fibrillation.

BACKGROUND: We tested the hypothesis that cycle length-dependent cardiac contractility in atrial fibrillation is primarily governed by the negative interval-force relation in patients with normal and depressed systolic function. METHODS AND RESULTS: We performed two-dimensional guided M-mode echocardiography in 41 patients (mean age, 69 +/- 4 years; range, 48 to 92 years; 19 men, 11 women). Twelve patients had objective evidence of left ventricular systolic dysfunction (CMP; mean ejection fraction, 37% +/- 7%) in the absence of coronary artery disease (CAD), 13 patients had documented CAD (mean ejection fraction, 43% +/- 6%), and 16 patients had normal resting left ventricular systolic function (mean ejection fraction, 58% +/- 7%). Simultaneous beat-to-beat blood pressure, end-systolic and end-diastolic dimension, circumferential velocity of fiber shortening (Vcf), and end-systolic wall stress (ESWS) were calculated for all patients. All three groups showed a significant linear relation between beat-to-beat Vcf and Vcf corrected for afterload (represented as the Vcf/ESWS ratio) and preceding cycle length. There was, however, no significant difference in the relation between either of these variables and cycle length among the three groups. There was also no difference in the rate of change in either Vcf or Vcf corrected for afterload (Vcf/ESWS ratio) from beat-to-beat among the three groups. Control patients with normal systolic function showed greater Vcf at any given cycle length compared with patients with CMP or CAD. CONCLUSION: Our data show that, for each beat in atrial fibrillation, Vcf and Vcf/ESWS ratio are decreased after shorter cycle lengths and increased after long cycles, but there is no significant attenuation of this effect in patients with systolic dysfunction with or without coronary disease compared with controls. Thus, the negative interval-force relation, the predominant determinant of beat-to-beat variation in contractility in atrial fibrillation, is preserved in patients with CAD or reduced left ventricular systolic function.

Aged↗
PubMed1998

Role of echocardiography in patients undergoing elective cardioversion of atrial fibrillation.

Echocardiography has emerged as a fundamental tool in the evaluation of patients with atrial fibrillation (AF). Transthoracic echocardiography remains a primary tool for the evaluation and management of many patients presenting with their first episode of AF, but it is not adequate for exclusion of atrial thrombi. TEE offers excellent visualization of the atria and accurate identification or exclusion of thrombi. In concert with therapeutic anticoagulation, a TEE-guided approach to early cardioversion appears to have a safety profile similar to that of conventional therapy (1 month of precardioversion warfarin). The TEE-guided approach offers the advantages of simplified anticoagulation management and shorter duration of sustained AF, thereby allowing for a more rapid recovery of atrial mechanical function. Warfarin should be continued for 1 month after cardioversion to allow for more complete recovery of atrial function and for prophylaxis should the patient revert to AF. Cost-effectiveness models demonstrate that TEE-guided cardioversion represents a cost-effective strategy, but only if the transthoracic echocardiogram is omitted. For patients with a thrombus on the initial TEE, follow-up TEE (to document thrombus resolution) is recommended before cardioversion.

Anticoagulants↗
PubMed1998

Serum cholesterol levels are underevaluated and undertreated.

We reviewed data from 147 patients followed at a Veterans Administration hospital regarding management of hypercholesterolemia. Less than one half of patients with lipid analysis who met Adult Treatment Panel II/National Education Cholesterol Program guideline criteria for initiation of medical therapy received lipid-lowering agents in 1 year of follow-up.

Adult↗
PubMed1998

Likelihood of spontaneous conversion of atrial fibrillation to sinus rhythm.

OBJECTIVES: We sought to determine the likelihood and predictors of spontaneous conversion to sinus rhythm of recent-onset atrial fibrillation (symptoms <72 h). BACKGROUND: Although spontaneous conversion of recent-onset atrial fibrillation is common, the likelihood and clinical and echocardiographic predictors have not been fully defined. Such data would be important for management of patients in whom early cardioversion is desired: Cardioversion could be delayed in patients with a high likelihood of spontaneous conversion, and it could be expeditiously pursued if spontaneous conversion is unlikely. METHODS: We screened 1,822 consecutive adults admitted to the hospital with atrial fibrillation and prospectively identified 356 patients (45% male, mean age +/- SD 68 +/- 16 years) with atrial fibrillation of <72-h duration. The occurrence of spontaneous conversion to sinus rhythm and clinical and echocardiographic data were identified through retrospective chart review. RESULTS: Spontaneous conversion to sinus rhythm occurred in 68% of the study group (n = 242; 95% confidence interval [CI] 63% to 73%). Among patients with spontaneous conversion, the total duration of atrial fibrillation was <24 h in 159 (66%), 24 to 48 h in 42 (17%) and >48 h in 41 (17%) (p < 0.001). Logistic regression analysis of clinical data identified presentation <24 h from onset of symptoms as the only predictor of spontaneous conversion (odds ratio 1.8, 95% CI 1.4 to 2.4, p < 0.0001). Normal left ventricular systolic function was more common among patients with spontaneous conversion (p = 0.03), but it was not an independent predictor of conversion. Left atrial dimension was similar between groups. CONCLUSIONS: Spontaneous conversion to sinus rhythm occurs in almost 70% of patients presenting with atrial fibrillation of <72-h duration. Presentation with symptoms of <24-h duration is the best predictor of spontaneous conversion.

Aged↗
PubMed1998

Cardiac performance early after cardioversion from atrial fibrillation.

BACKGROUND: The mechanism for early improvement in cardiac function after cardioversion from atrial fibrillation is unknown. METHODS: We measured ventricular volumes and load-independent contractility during atrial fibrillation and within 24 hours after cardioversion to sinus rhythm in 15 adult patients (10 men, 5 women; mean age 63+/-4 years, range 31 to 81 years). Duration of atrial fibrillation ranged from <1 day to 6 months. RESULTS: After cardioversion, left ventricular ejection fraction increased from 51%+/-4% to 61%+/-4% (P=.001, 95% confidence intervals for the difference, 7% to 15%), stroke volume increased from 57+/-4 mL to 76+/-6 mL (P < .001, 95% confidence intervals 8 to 32 mL), and mean cycle length increased from 0.77+/-.04 seconds in atrial fibrillation to 1.02+/-.04 seconds in sinus rhythm (P=.002, 95% confidence intervals, 0.1 to 0.4 seconds). Cardiac contractility, as expressed by the slope and the intercept of the relation between rate-corrected circumferential velocity of fiber shortening and end-systolic wall stress (Vcfc/ESWS) remained unaltered in 13 of 15 patients, suggesting that intrinsic inotropic state was unchanged immediately after return of normal sinus rhythm. Finally, a significant correlation was observed between improvement in stroke volume and peak A-wave velocity (r=0.79, P=.035). CONCLUSION: Both left ventricular stroke volume and ejection fraction increase immediately after cardioversion, whereas intrinsic cardiac contractility is largely unchanged. These data suggest that the mechanism of this increase is enhanced left ventricular diastolic filling due mostly to increased cycle length and return of left atrial mechanical function.

Adult↗
PubMed1997

Risk for clinical thromboembolism associated with conversion to sinus rhythm in patients with atrial fibrillation lasting less than 48 hours.

BACKGROUND: It has been assumed that cardioversion in patients with atrial fibrillation lasting less than 48 hours is associated with a low risk for thromboembolism. However, no clinical data support this assumption. OBJECTIVE: To determine the incidence of cardioversion-related clinical thromboembolism among patients presenting with atrial fibrillation lasting less than 48 hours. DESIGN: Patients were prospectively identified on admission, and clinical data on the duration of atrial fibrillation were recorded. Data on cardioversion and thromboembolism were obtained retrospectively from hospital and outpatient records. SETTING: Academic medical center. PATIENTS: 1822 consecutive patients admitted to the hospital for atrial fibrillation were screened. Three hundred seventy-five adults (mean age +/- SD, 68 +/- 16 years) with atrial fibrillation that had lasted less than 48 hours were identified. One hundred eighty-one patients (48.3%) had a history of atrial fibrillation; 23 (6.1%) had a history of thromboembolism. RESULTS: 357 patients (95.2%) converted to sinus rhythm during the index admission; spontaneous conversion occurred in 250 patients (66.7%) and active pharmacologic or electrical conversion was done in 107 patients (28.5%). Three patients (0.8% [95% CI, 0.2% to 2.4%]), all of whom had converted spontaneously after ventricular rate control was begun, had a clinical thromboembolic event: One had a stroke, 1 had a transient ischemic attack, and 1 had a peripheral embolus. None of these 3 patients had a history of atrial fibrillation or thromboembolism, and all had normal left ventricular systolic function. CONCLUSION: Among patients presenting with atrial fibrillation that was clinically estimated to have lasted less than 48 hours, the likelihood of cardioversion-related clinical thromboembolism is low. These data support the current recommendation for early cardioversion in these patients.

Adult↗
PubMed1996

Endocarditis in an urban hospital in the 1990s.

OBJECTIVES: To analyze the clinical characteristics and outcome of 159 consecutive patients with endocarditis who presented to an inner-city hospital from 1990 onward and to elucidate the most current problems and advances in the management of endocarditis. METHODS: One hundred eighty-two consecutive cases (in 159 patients) met diagnostic criteria for endocarditis, including histopathologic evidence or multiple positive blood cultures without another primary source, and appropriate signs or symptoms. Transthoracic echocardiography was performed for 171 cases, and 36 patients underwent transesophageal echocardiography. RESULTS: Sixty-seven percent of the patients were known drug users; more than 80% of these were positive for human immunodeficiency virus. Fever, malaise, and fatigue occurred in more than 95%, but other signs were neither sensitive nor specific, and classic microvascular phenomena were uncommon. Blood cultures were positive in 96%, all 7 patients with negative cultures had received prior antibiotic therapy. Staphylococcus aureus was the most common organism, and a significant increase in S aureus infections was noted for tricuspid endocarditis (chi 2 = 71.07, P = .003). The mitral (n = 51) and tricuspid (n = 49) valves were the most common sites of infection. Underlying heart disease was only identified in one fourth of the cases. Transesophageal echocardiography identified vegetation in 34 of 36 studies, 16 of which had negative transthoracic echoes. Five of 6 patients with documented abscesses died within 7 months. A systemic embolism occurred in nearly a third (n = 51) of the cases. Large vegetations (> 20 mm) were significantly correlated with an increased frequency of embolization (chi 2 = 6.77, P = .009), but vegetation mobility was not. Cardiac surgery was performed in 24 patients; there were 2 perioperative deaths. CONCLUSIONS: The changing clinical spectrum of endocarditis exemplified in our series has important implications for diagnosis and management. Close attention to appropriate risk factors can contribute to optimal management of those factors and improve prognosis.

Adult↗
PubMed1996

Effect of combination therapy with lipid-reducing drugs in patients with coronary heart disease and "normal" cholesterol levels. A randomized, placebo-controlled trial. Harvard Atherosclerosis Reversibility Project (HARP) Study Group.

BACKGROUND: Combination drug therapy has been shown to decrease cholesterol levels in hyperlipidemic patients. However, its efficacy has not been well studied in patients previously considered to be normolipidemic, many of whom are now candidates for this therapy. OBJECTIVE: To determine the efficacy and tolerability of multidrug therapy designed to improve low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol levels in patients with coronary heart disease and average lipid levels. DESIGN: Randomized, placebo-controlled, 2.5-year trial comparing patients receiving usual care with patients receiving stepped-care drug therapy. INTERVENTION: Stepped-care therapy (pravastatin, nicotinic acid, cholestyramine, and gemfibrozil) to decrease total cholesterol levels to less than 4.1 mmol/L (160 mg/dL) and the ratio of LDL cholesterol to HDL cholesterol to less than 2.0. SETTING: 2 academic, urban, tertiary care hospitals. PATIENTS: 91 patients (80 men and 11 women) with coronary heart disease, a mean age of 60 years, total cholesterol levels less than 6.4 mmol/L (250 mg/dL) at baseline, and ratios of total cholesterol to HDL cholesterol greater than 4.0 at baseline. MEASUREMENTS: Fasting serum lipoprotein profile, fasting apolipoprotein levels, and frequency of adverse effects. Patients were assessed every 6 weeks during drug titration and every 3 months thereafter. RESULTS: Mean lipid levels at baseline were as follows: total cholesterol, 5.5 mmol/L (214 mg/dL); LDL cholesterol, 3.6 mmol/L (140 mg/dL); HDL cholesterol, 1.1 mmol/L (42 mg/dL); and triglycerides, 1.8 mmol/L (159 mg/dL). With pravastatin, changes in levels from baseline were -22% for total cholesterol, -32% for LDL cholesterol +8% for HDL cholesterol, and -15% for triglycerides (P < 0.001 for all comparisons). With the addition of 1.5 g of nicotinic acid, additional changes were -6% for total cholesterol (P < 0.002). -11% for LDL cholesterol, +8% for HDL cholesterol, and -10% for triglycerides (P < 0.001 for all comparisons). With 2.25 to 3 g of nicotinic acid, these changes were -7% for total cholesterol (P = 0.007), -14% for LDL cholesterol (P < 0.001), +6% for HDL cholesterol (P = 0.02), and -13% for triglycerides (P = 0.03). With cholestyramine, total cholesterol and LDL cholesterol levels were unchanged compared with the previous step; the change in HDL cholesterol level was -8% (P = 0.03); and the change in triglyceride level was +46% (P < 0.001). With gemfibrozil, total cholesterol level was unchanged; the additional change in LDL cholesterol level was +12% (P = 0.09); the change in HDL cholesterol level was +12% (P = 0.03); and the change in triglyceride level was -37% (P < 0.001). Apolipoprotein B levels decreased by 25% overall (P < 0.001); lipoprotein(a) levels did not change significantly. Adverse effects were primarily attributable to nicotinic acid or cholestyramine. In 18 of the 35 patients (50%) whose baseline LDL cholesterol levels were greater than 3.35 mmol/L (130 mg/dL), pravastatin decreased LDL cholesterol levels to 2.6 mmol/L (100 mg/dL) or less by 6 weeks; 70% of patients needed combination therapy to reach this National Cholesterol Education Program goal during the 2.5 years of the study. Adding nicotinic acid to pravastatin produced LDL cholesterol levels of 2.6 mmol/L or less in 15 more of these 35 patients, so that 94% (n = 33) of the patients receiving these two drugs reached this goal. CONCLUSIONS: To reach current goals for LDL cholesterol levels, most normolipidemic patients with coronary heart disease in this study needed combination therapy. Pravastatin with nicotinic acid and pravastatin with gemfibrozil are well-tolerated combinations that can maintain target LDL cholesterol levels, decrease triglyceride levels, and increase HDL cholesterol levels. Adding resin to these combinations produced no further benefit.

Algorithms↗
PubMed1996

Torsades de pointes from terfenadine and sotalol given in combination.

A patient receiving sotalol developed recurrent torsades de pointes following the addition of terfenadine (Seldane) to her medical regimen. A 71-year-old woman with a history of atrial fibrillation successfully suppressed with sotalol, 80 mg bid, was started on terfenadine, 60 mg bid. Eight days later, she developed repeated self-terminating episodes of torsades de pointes. Sotalol and terfenadine were discontinued, and no further arrhythmia was observed after 72 hours of temporary pacing was discontinued.

Aged↗