Is nurse-supervised exercise stress testing safe practice?

OBJECTIVE: Nurses have been performing exercise stress tests (EST) without medical supervision since 1978 in our hospital-based cardiac rehabilitation unit. This study was conducted to examine the incidence of cardiovascular complications and to describe the competency-based training program for the nurses performing the EST. DESIGN: Descriptive, retrospective audit of prospective data. SETTING: Single comprehensive cardiac rehabilitation center in a large tertiary referral hospital in western Sydney, Australia. SUBJECTS: Seventeen thousand, four hundred and sixty-seven patients were included in this study over a 12-year period. METHOD: Data were collected on all ESTs performed by the cardiac rehabilitation nurses from January 1986 to December 1997 in relation to serious cardiovascular complications and other EST parameters. RESULTS: In this study, 17,467 ESTs were performed on 5054 patients who had 6273 separate presentations. The most common entry diagnosis was after an acute myocardial infarction (50%). The mean age was 58 +/- 10.5 years (range 15 to 87 years; 80% male). The left ventricular ejection fraction (n = 2822) was 49% +/- 14%. In a subgroup analysis of 14,454 patients, 14% had a positive EST (ST segment >1.9 mm depression). There were no deaths associated with the EST, and there were 13 major complications in 12 patients. This figure included no cardiac arrests, 11 episodes of conscious sustained ventricular tachycardia, 1 reinfarction, and 1 mitral valve rupture, representing a 0% mortality rate and a 0.075% major morbidity rate. CONCLUSION: This study shows that nurse-supervised EST of higher risk patients in the hospital-based cardiac rehabilitation setting has been a safe practice from a mortality and morbidity rate perspective. This finding may be accounted for by the high training standard and reaccreditation of the nurses on the advanced practice of performing EST.

Rapid intravenous infusion of d-1 sotalol: time to onset of effects on ventricular refractoriness, and safety.

d-1 sotalol is one of the most effective antiarrhythmic agents currently available for ventricular tachyarrhythmias, but the recommended infusion rate of 10-20 min is too slow for rapid pharmacological termination of sustained ventricular tachycardia (VT) or for use during cardiac arrest. The safety of the drug and time lag from its rapid administration to onset of significant effects on ventricular refractoriness is unknown. One hundred and nine patients with a history of spontaneous and inducible sustained ventricular tachyarrhythmias were studied. d-1 sotalol (1.5 mg.kg-1) was infused over 5 min in the first 57 patients (mean age 61 +/- 13 years, mean ejection fraction 37 +/- 15%, range 15-70%). d-1 sotalol was then given over 1 min in the next 52 patients (mean age 61 +/- 12 years, mean ejection fraction 35 +/- 11%, range 18-58%). The time course of change in right ventricular effective refractory period (RVERP) was measured in 15 consecutive patients following the 5 min infusion and in all 52 patients following the bolus injection. Following the 5 min infusion, RVERP increased rapidly from a baseline of 231 +/- 17 ms, reaching a plateau of 268 +/- 23 ms at 10 min. Following the 1 min injection, RVERP increased virtually immediately from a baseline of 237 +/- 25 ms to reach a plateau of 271 +/- 31 ms at 5 min. Two patients (one in each group) developed symptomatic hypotension; both responded to volume replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Double-blind trial of lignocaine versus sotalol for acute termination of spontaneous sustained ventricular tachycardia.

The efficacy of antiarrhythmic drugs for terminating sustained ventricular tachycardia (VT) has been disappointing. Lignocaine is the traditional drug but it is not very effective. Sotalol, one of the most effective drugs in suppressing spontaneous or induced VT, should theoretically be useful in this setting. We have compared lignocaine with sotalol for the acute termination of spontaneous sustained VT not causing cardiac arrest in 33 patients (26 males, 7 females, aged 21-90) whose underlying heart disease was old myocardial infarction (28), acute myocardial infarction (2), dilated cardiomyopathy (1), or idiopathic cardiomyopathy (2). Left-ventricular ejection fraction was 35% (range 18-76%). Patients were randomly allocated in a double-blind fashion to lignocaine 100 mg (n = 17) or sotalol 100 mg (n = 16) given intravenously over 5 min. Those with persistent VT 15 min after onset of administration of the first drug were crossed over to the other drug. Sotalol was significantly more effective than lignocaine whether analysed on an intention-to-treat basis (69% vs 18%; 95% confidence interval for absolute difference of 51% 22-80%, p = 0.003) or by analysis limited to the 31 patients with subsequent electrophysiologically proven VT (69% vs 20%). 1 patient in each group required cardioversion after the first drug. Tachycardia persisted in 14 patients in the lignocaine group and 4 in the sotalol group after 15 min. Tachycardia ceased in 7 (50%) patients who crossed over to sotalol, and in 1 patient who crossed over to lignocaine. There was 1 death in each group after the first drug and 1 death after both drugs. We conclude that sotalol was superior to lignocaine for the acute termination of sustained VT. The incidence of adverse effects was similar for the two drugs.