ABSTRACT
AIMS: Dobutamine stress echocardiography is a time-consuming test, often requiring atropine at the end of the protocol to achieve target heart rate (HR). We examined whether earlier administration of atropine in appropriate patients would shorten test time and increase the likelihood of achieving peak HR. METHODS: Two hundred and seventy consecutive patients were randomized prospectively to conventional or early atropine protocols. Of these, 120 patients with an inadequate HR response [mid-30 microg/kg/min HR<100 (age <50) or <90 (age >50); or mid-40 microg/kg/min stage HR<120 (age <50) or <110 (age >50)] were included in the analysis. The remaining patients were used in a model to define which patients are likely to require atropine. RESULTS: The 61 patients receiving early-atropine had decreased test-time relative to the 59 not receiving early-atropine (17:05 vs. 18:24 min:sec, P=0.014) accompanied by a 10% reduction in total dobutamine dose (P=0.008). Their HR at end of 40 microg/kg/min was 123+/-18 vs. 105+/-17 respectively, P<0.0001. Only 7% of the early-atropine group failed to reach target HR vs. 15% not receiving early-atropine. By multivariate analysis, age (P<0.0001), HR at end of 30 microg/kg/min stage (P<0.0001), beta-blocker use (P=0.009) and baseline HR (P=0.04) were predictors of need for atropine. CONCLUSION: Giving atropine early in appropriate patients can reduce test times without an increase in side effects. Our model enables accurate prediction of these patients.
Subject(s)
Adrenergic beta-Agonists/administration & dosage , Anti-Arrhythmia Agents/administration & dosage , Atropine/administration & dosage , Dobutamine/administration & dosage , Echocardiography, Stress , Adrenergic beta-Agonists/adverse effects , Adult , Aged , Algorithms , Anti-Arrhythmia Agents/adverse effects , Arrhythmias, Cardiac/chemically induced , Arrhythmias, Cardiac/epidemiology , Atropine/adverse effects , Dobutamine/adverse effects , Dose-Response Relationship, Drug , Echocardiography, Stress/methods , Endpoint Determination , Female , Heart Rate/drug effects , Humans , Incidence , Israel/epidemiology , Male , Middle Aged , Multivariate Analysis , Predictive Value of Tests , Prospective Studies , Time FactorsABSTRACT
BACKGROUND: Our aim was to study the effect of collateral flow, stenosis severity, antegrade flow, and location of the lesion on regional myocardial function in patients with chronic left anterior descending (LAD) coronary artery disease. METHODS AND RESULTS: Seventy-four patients who underwent coronary angiography and ventriculography were divided into three groups: group A (n = 9), patients with normal coronary angiogram and ventriculogram; group B (n = 32), patients with LAD stenosis >75%; and group C, 33 patients with LAD occlusion. The effect of collateral flow, stenosis severity, location, and antegrade flow on regional myocardial function in the LAD territory was studied. Regional function was impaired in both groups B and C. In group B, univariate analysis confirmed that antegrade flow had a significant effect on regional function (p < 0.02). With the use of multiple regression, none of the other variables had an additional independent effect. In group C, no significant correlation was found between regional function and the study variables by univariate analysis; however, multiple regression revealed a significant correlation between anterobasal function, the lesion site (p = 0.01), and collateral flow (p = 0.02). CONCLUSIONS: In patients with LAD stenosis, antegrade flow has the strongest effect on regional myocardial function, with no additional effect of visible collaterals. In patients with LAD occlusion, both angiographic collateral flow and the site of the lesion have a significant effect on the function of the anterobasal area.
