QTc dynamics during long-term Holter recording
Patients underwent long term Holter monitoring for an average of 6.2 ± 1.2 days. Median baseline QTc (defined as the median QTc during first hour after CV) was 452 ± 52 msec and was significantly lower than the median QTc during the continuous Holter monitoring (467 ± 47 msec, p=0.01 for comparison). The maximal median QTc occurred 44 hours post CV and was 474 ± 100 msec (p<0.001 for comparison with baseline QTc). Following this peak, the QTc returned to the baseline QTc 132 hours post CV, with a median QTc was 458 ± 70 msec (p=0.58 for comparison with baseline QTc) Figure 2. The baseline clinical characteristics were similar between those who had significant prolongation within the 44 hours post CV and those who developed it after. A trend towards more Amiodarone use was seen in those who developed a later QTc prolongation (87% vs 63%, p=0.07).