Response to Letter by Atanassova
We were interested to read Dr Atanassova’s comments regarding our article. In the design of our study, we excluded patients with a history of myocardial infarction and congestive heart failure (CHF) in order to focus on the pathogenesis of acute cardiac injury and dysfunction. Though subarachnoid hemorrhage (SAH) patients have prevalent hypertension and smoking, the majority of patients are women, the mean age is <60 years, and the prevalence of diabetes mellitus and dyslipidemia is low. These factors likely limit the prevalence of overt or occult coronary artery disease (CAD) and CHF in this population. In screening for a total cohort size of 300 patients, <10 patients were excluded because of a history of prior myocardial infarction or CHF.
Though it is impossible to precisely predefine the cardiac status of all victims of sudden events such as SAH, the available data indicate that cardiac enzyme,1 echocardiographic,2 and electrocardiographic3 abnormalities normalize over time, which would not be expected if the abnormalities preceded the SAH.
In our multivariate models predicting troponin release and left ventricular systolic dysfunction, we did adjust for Hunt&Hess grade, a reasonable surrogate for initial neurological status. We did not adjust for hypertension or pre-existing CAD in order to preserve the statistical power of the models, given the limited sample size. In addition, in other analyses of this dataset, we have shown that CAD and coronary risk factors, including hypertension, smoking, diabetes mellitus, and dyslipidemia, are not predictive of troponin release1 or left ventricular systolic dysfunction.4
Tung P, Kopelnik A, Banki N, Ong K, Ko N, Lawton MT, Gress D, Drew B, Foster E, Parmley WW, Zaroff J. Predictors of neurocardiogenic injury after subarachnoid hemorrhage. Stroke. 2004; 35: 548–551.
Banki N, Kopelnik A, Tung P, Lawton MT, Gress D, Drew B, Dae M, Foster E, Parmley W, Zaroff J. Prospective analysis of prevalence, distribution, and rate of recovery of left ventricular systolic dysfunction in patients with subarachnoid hemorrhage. J Neurosurg. 2006; 105: 15–20.
Sommargren CE. Electrocardiographic abnormalities in patients with subarachnoid hemorrhage. Am J Crit Care. 2002; 11: 48–56.