Does infection prolong the QT interval?

The corrected QT (QTc) interval is a strong predictor of ischaemic heart disease and cardiovascular mortality. It may trigger lethal arrhythmias and sudden death. Risk factors include electrolyte disorders, medications, prior cardiovascular disease and genetic predisposition. We previously demonstrated that QTc intervals are prolonged in patients hospitalised with pneumonia, regardless which antibiotics were given. It is unclear whether QTc prolongation is associated with pneumonia itself or whether it occurs with other infections.

To investigate any association between hospitalisation for infection and QTc prolongation.

We enrolled 169 patients, 160 of whom were used for analysis. QTc was measured in seconds by routine electrocardiogram (ECG) on admission. Subsequently, daily ECG were performed for 3 days, or until discharge (whichever occurred sooner). When clinically significant QTc prolongation was detected, possible causes were investigated.

Clinically significant prolongation was not observed in any patient. The QTc was slightly longer in patients hospitalised for pneumonia or upper respiratory tract infections on admission. It was also prolonged in men, in patients with ischaemic heart disease, hypertension, history of cerebrovascular accident or cancer. A very slight trend for prolongation was observed between the first and second day of monitoring, however it later returned to baseline levels. Nearly 54% of study participants had positive systemic inflammatory response syndrome scores, however no association was detected between their score and baseline QTc, or any subsequent prolongation.

We found no association between hospitalisation due to infection and prolongation of the QTc interval.