Response to Letter by Stahrenberg et al
We thank Stahrenberg et al for the interest shown in our research letter.1 Dr Stahrenberg et al have emphasized the necessity for a score making it possible to target patients at high risk for paroxysmal atrial fibrillation, the more difficult documentation of which is restricted to the availability of expensive equipment and patient compliance. Dr Stahrenberg et al support a multicentric validation study, an important step for proposing screening algorithms of atrial fibrillation with an optimized cost–benefit ratio in the checkup for secondary prevention of cerebral infarction.
Dr Stahrenberg et al underline that the score is based on a sample of unselected patients and might be less successful in the documentation of episodes of paroxysmal arrhythmia. In this preliminary study, we did not make the distinction between permanent arrhythmia and paroxysmal arrhythmia for which the embolic risk and the thromboembolic risk factors are the same to obtain a profile consistent with routine activity. Note that in the absence of this distinction, the diagnosis of arrhythmia in the initial electrocardiogram did not assume permanence of the disorder. Our multivariate model is compatible with the literature of cerebral infarction associated with atrial fibrillation.2 Score for the Targeting of Atrial Fibrillation (STAF) expresses these data in score form. As Dr Stahrenberg et al emphasize, the dilatation of the left atrium is a criterion of remodeling depending on the duration of the atrial fibrillation. It also appears to be the result of echographic anomalies (left valvulopathy, left ventricular dysfunction, and left ventricular hypertrophy) associated with the documentation of atrial fibrillation in our univariate analysis. Thus, this echographic item retained in our score does not reflect only the prolonged nature of the arrhythmia. It is also correlated with the etiologies and the cardiological thromboembolic factors of the atrial fibrillation independently of its permanent or paroxysmal nature. The other 3 clinic radiological items forming the score do not have reasons to be influenced by the nature of the arrhythmia, permanent or not. The undocumented 30% rate of patients in atrial fibrillation on admission does not seem to us to be negligible when it is known that the approach for detection of arrhythmia is often limited to a 24-hour Holter electrocardiogram that may be put in the wrong by its low sensitivity.3 Because of this, we have tested the STAF reproducibility in this subgroup. The sensitivity and specificity observed in this sample according to the total of the score can be superimposed on the calculated values on all patients.
STAF has not been proposed to replace the tools for documentation of atrial fibrillation. We support the necessity for validating the score on a multicentric population and optimizing its predictive capacity. In the absence of current recommendations, it indeed, by its negative predictive value, could help the clinician on screening atrial fibrillation with an optimized cost–benefit ratio. The STAF II perspective will perhaps use the implementation of biological markers as recent literature data suggest.4
Suissa L, Bertora D, Lachaud S, Mahagne MH. Score for the Targeting of Atrial Fibrillation (STAF): a new approach to the detection of atrial fibrillation in the secondary prevention of ischemic stroke. Stroke. 2009; 40: 2866–2868.
Kimura K, Minematsu K, Yamaguchi T. Atrial fibrillation as a predictive factor for severe stroke and early death in 15,831 patients with acute ischaemic stroke. J Neurol Neurosurg Psychiatry. 2005; 76: 679–683.
Liao J, Khalid Z, Scallan C, Morillo C, O'Donnell M. Noninvasive cardiac monitoring for detecting paroxysmal atrial fibrillation or flutter after acute ischemic stroke: a systematic review. Stroke. 2007; 38: 2935–2940.
Montaner J, Perea-Gainza M, Delgado P, Ribo M, Chacon P, Rosell A, Quintana M, Palacios ME, Molina CA, Alvarez-Sabin J. Etiologic diagnosis of ischemic stroke subtypes with plasma biomarkers. Stroke. 2008; 39: 2280–2287.