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Multivariate analysis of risk factors for QT prolongation following subarachnoid hemorrhage
Shinji Fukui1, Hiroshi Katoh, Nobusuke Tsuzuki
1Department of Neurosurgery, National Defense Medical College, Tokorozawa, Japan. ndmcsf@aol.com
Insights
Subarachnoid hemorrhage (SAH) can prolong the corrected QT (QTc) interval. Female sex and low potassium (hypokalemia) are identified as independent risk factors for severe QTc prolongation in SAH patients.
Area of Science:
- Cardiology
- Neurology
- Critical Care Medicine
Background:
- Subarachnoid hemorrhage (SAH) frequently leads to corrected QT (QTc) interval prolongation in the acute phase.
- Identifying risk factors for QTc prolongation is crucial for managing SAH patients.
Purpose of the Study:
- To investigate independent risk factors for QTc prolongation in patients following SAH.
- To utilize multivariate analysis for risk factor identification.
Main Methods:
- A cohort of 100 patients admitted within 24 hours of SAH onset was studied.
- Standard 12-lead electrocardiography (ECG) and serum electrolyte/hormone level measurements were performed.
- QT intervals were corrected for heart rate using the Bazett formula.
Main Results:
- The average QTc interval was 466 ms, with 470 ms used as a cutoff for severe prolongation.
- Univariate analysis indicated associations between QTc interval, sex, and serum potassium, calcium, and glucose levels.
- Multivariate analysis identified female sex and hypokalemia as independent risk factors for severe QTc prolongation, with relative risks of 4.45 and 4.53, respectively.
Conclusions:
- Female sex and hypokalemia are significant independent risk factors for severe QTc prolongation in the context of SAH.
- These findings highlight the importance of monitoring electrolytes and considering sex in SAH patient management.
Background:
Subarachnoid hemorrhage (SAH) often causes a prolongation of the corrected QT (QTc) interval during the acute phase. The aim of the present study was to examine independent risk factors for QTc prolongation in patients with SAH by means of multivariate analysis.
Method:
We studied 100 patients who were admitted within 24 hours after onset of SAH. Standard 12-lead electrocardiography (ECG) was performed immediately after admission. QT intervals were measured from the ECG and were corrected for heart rate using the Bazett formula. We measured serum levels of sodium, potassium, calcium, adrenaline (epinephrine), noradrenaline (norepinephrine), dopamine, antidiuretic hormone, and glucose.
Results:
The average QTc interval was 466 +/- 46 ms. Patients were categorized into two groups based on the QTc interval, with a cutoff line of 470 ms. Univariate analyses showed significant relations between categories of QTc interval, and sex and serum concentrations of potassium, calcium, or glucose. Multivariate analyses showed that female sex and hypokalemia were independent risk factors for severe QTc prolongation. Hypokalemia (<3.5 mmol/l) was associated with a relative risk of 4.53 for severe QTc prolongation as compared with normokalemia, while the relative risk associated with female sex was 4.45 as compared with male sex. There was a significant inverse correlation between serum potassium levels and QTc intervals among female patients.
Conclusion:
These findings suggest that female sex and hypokalemia are independent risk factors for severe QTc prolongation in patients with SAH.