Statistical Analysis
Values were analyzed using standard statistical methods. T-tests were
used for continuous variables. All statistical analyses were done using
Microsoft Excel.
Results
A total of 50 consecutive CCTAs were included in this study, 30 men and
20 women. The average age was 55.4 ± 14.1 years. Medical history
included hypertension (64%), diabetes (50%) and CAD (10%). LVH was
present in 9 patients (18%) but was mild in all cases. Heart failure
was present in 9 patients (18%), 4 of whom had systolic dysfunction
with an average EF for the study being 57.0 ± 8.6 % determined by
echocardiography. The mean left ventricular internal diameter at end
diastole (LVIDd) and interventricular septum thickness (IVS) were 46.7
mm and 10.2 mm, respectively. The mean distance from the His Bundle to
the first septal perforator (His-SP) along the line connecting the His
bundle to the RV apex (His-RV apex) was 27.17 ± 7.7 mm, median 26.9 mm,
range 13.0 to 44.7 mm. There was no significant difference by gender for
mean distance (28.1 mm in men vs 25.6 mm in women, p=0.26). Given the
variability in cardiac structure among patients, this ratio between the
His-SP distance and the His-RV Apex distance was also measured. The mean
His-SP:His-RV Apex was 0.302 and the median was 0.298. The relationship
between the His-SP and the His-RV Apex distances are shown inFigure 2 . The percentage of patients who met certain distance
and ratio cutoffs between the His Bundle and the first septal perforator
are shown in Table 1 .