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The Follow-Up Serial Infusions of Nesiritide pilot study was designed to assess the safety and tolerability of outpatient serial infusions of nesiritide in 210 patients with decompensated heart failure who were randomly assigned to usual care only or usual care plus weekly infusions of nesiritide at dosages of 0.005 or 0.01 microg/kg/min for 12 weeks. The mean age +/- SD of the entire population was 67 +/- 13 years; 70% were men, and 80% were white. Mean baseline serum creatinine levels were 1.8 +/- 0.7 mg/dl, and mean left ventricular ejection fraction was 0.28 +/- 0.15%. Diabetes mellitus was present in 106 patients (50%), and atrial arrhythmias were present in 100 patients (48%). A totalof 1,645 nesiritide infusions was administered; 11 (1%) were discontinued due to an adverse event. All treatment groups had a similar frequency of adverse events and experienced improvements in quality of life. Administration of nesiritide resulted in acute decreases in aldosterone and endothelin-1 concentrations. Although there were no statistically significant differences among groups by outcome, prospectively defined higher risk subgroups demonstrated significant decreases in cardiovascular events. These results demonstrate the safety and feasibility of administering nesiritide in an outpatient setting. Additional studies are needed to determine the effect of outpatient serial infusions of nesiritide on rates of morbidity and mortality in advanced heart failure.

A 2-tiered noninvasive cardiac risk stratification algorithm was first evaluated in a test population with planar thallium myocardial perfusion imaging and subsequently in a validation population using single-photon emission computed tomographic (SPECT) thallium myocardial perfusion imaging. This study examines if SPECT imaging was as predictive of cardiac death as planar imaging and also if SPECT imaging predicted nonfatal cardiac events in the patient population. Renal transplant candidates were evaluated using a 2-tiered noninvasive cardiac risk stratification algorithm. The first tier of risk assessment utilized 5 variables: age >50 years, insulin-dependent diabetes mellitus, abnormal electrocardiogram, and a history of either angina or congestive heart failure. Patients without risk factors were considered low risk and underwent no further cardiac evaluation. Patients with ≥1 risk factor were considered high risk and underwent a second tier of risk assessment with planar (n = 95) or SPECT (n = 112) imaging. In the test population, 13 of 16 cardiac deaths (81%) occurred in high-risk patients with abnormal planar studies. In the validation group, all cardiac deaths (5 of 60) and nonfatal cardiac events (13 of 60) occurred in high-risk patients with abnormal SPECT studies. SPECT imaging was at least as predictive as planar imaging and also predicted nonfatal as well as fatal cardiac events. Pretransplant risk stratification by clinical variables identified low-risk patients who may not require further cardiac evaluation and high-risk patients with normal SPECT imaging who may not require angiography.

BACKGROUND Renal transplant candidates are at high risk of fatal and nonfatal cardiac events. METHODS This study evaluated five clinical risk factors--age at least 50 years, insulin-requiring diabetes mellitus, angina, congestive heart failure and an abnormal electrocardiogram (ECG) (excluding left ventricular hypertrophy)--that had been used in the first tier of a two-tiered prospectively applied risk stratification algorithm. RESULTS Using multiple logistic regression analysis, age at least 50 years, abnormal ECG, and diabetes mellitus were independently predictive of cardiac death. Of the two remaining clinical risk factors, the presence of angina had independent predictive value for nonfatal cardiac events (myocardial infarction, coronary angioplasty, bypass surgery, and unstable angina). The independent predictive value of congestive heart failure approached statistical significance. CONCLUSION Clinical risk-factor analysis is helpful in identifying renal transplant candidates at high risk for fatal or nonfatal cardiac events.

Objectives: The use of adenosine after radiofrequency catheter ablation of accessory pathways was prospectively studied to determine its utility for identifying patients at risk for recurrence of accessory pathway conduction and to guide therapy that might reduce late recurrence in this group. Background: Accessory pathway conduction recursin 5%–12% of patients following initially “successful” radiofrequency catheter ablation. Adenosine may facilitate conduction over accessory pathways that have been modified by radiofrequency delivery, thus identifying patients at risk for recurrence. Methods: Radiofrequency catheter ablation was performed in 109 patients. Prior to ablation, 12–18 mg of adenosine was administered. After ablation, when all evidence of accessory pathway conduction remained absent for at least 30 minutes, adenosine 12–18 mg was again administered. Results: Adenosine given prior to radiofrequency catheter ablation did not block accessory pathway conduction in any patient. Adenosine given after elimination of accessory pathway conduction induced complete atrioventricular and ventriculoatrial block in 95 patients; 11 (11.6%) subsequently had recurrence of accessory pathway function. Accessory pathway conduction was unmasked by adenosine in 12 patients (11.2%). After further deliveries of radiofrequency energy, 7 of these 12 patients subsequently demonstrated adenosine induced atrioventricular and ventriculoatrial block; 1 of these 7 patients experienced recurrence of accessory pathway conduction. The remaining 5 patients demonstrated persistent accessory pathway conduction only with adenosine; all experienced clinical recurrence of accessory pathway function. Conclusion: The use of adenosine after presumed successful radiofrequency catheter ablation may reveal persistent accessory pathway conduction. Elimination of this latent accessory pathway conduction reduces the risk for recurrence.

Radiofrequency catheter ablation is very effective in eliminating conduction over accessory pathways in patients with Wolff-Parkinson-White syndrome. However, accessory pathway conduction recurs in approximately 5 to 9 percent of patients in the weeks to months following ablation. We describe two cases in which intravenous adenosine revealed persistent accessory pathway conduction after apparently successful ablation, thus providing an indication for the delivery of further ablative therapy. Adenosine may improve the long-term efficacy of radiofrequency catheter ablation of accessory pathways by manifesting latent accessory pathway conduction.