QTc dispersion as a marker for medical complications after severe subarachnoid haemorrhage

Abstract

Background and objective: Morbidity from subarachnoid haemorrhage is common and results from complications including myocardial dysfunction and neurogenic pulmonary oedema causing hypotension and hypoxia--both major causes of secondary brain injury. Predicting patients at risk of developing these complications may facilitate early intervention.

Methods: Using QTc dispersion to assess repolarization inhomogeneity, patients who had suffered severe acute subarachnoid haemorrhage were studied in an intensive care unit. Electrocardiograms were recorded within 24 h of ictus. Subsequent development of myocardial dysfunction was defined as a requirement for inotropes, and neurogenic pulmonary oedema as a PaO2 (kPa)/FiO2 ratio < 40. Together they constituted cardiorespiratory compromise.

Results: Twenty-seven patients were recruited. QTc dispersion was greater in patients (74.1 ms, SD +/- 26.1) than in controls (48.3 ms, 12.0) P < 0.0001, 95% CI 14.6, 37.0. Thirteen patients developed cardiorespiratory compromise and had greater QTc dispersion (84.5 ms, 26.2) than patients who did not develop cardiorespiratory compromise (64.5 ms, 22.7) P = 0.046, 95% CI 0.3, 39.6. There was no difference in QTc dispersion between patients who did and those who did not develop myocardial dysfunction alone. Similarly, there was no difference in QTc dispersion between patients who did and those who did not develop neurogenic pulmonary oedema alone.

Conclusions: Increased QTc dispersion is associated with the later development of cardiorespiratory compromise in poor-grade subarachnoid haemorrhage patients. QTc dispersion may be used as a marker to predict impending clinical deterioration, providing an opportunity for early intervention.