Statistical Analysis
Statistical analysis was performed using SPSS v 25 (IBM corporation,
Armonk, NY). All missing data was excluded and outliers were included.
Categorical variables were compared using Chi-squared test or Fisher
exact test while continuous variables were compared using student’s
t-test or Mann-Whitney test for normally or non-normally distributions
respectively. Univariate regression was used to compare the primary
endpoint with baseline variables. Multivariate analysis was performed
using multi nominal regression analysis, with step-wise inclusion into
the model. Two tailed P values < 0.05 were considered
statistically significant. An exploratory analysis of the best
discriminators of AF-free HF events was performed using a
receiver-operator curve.
To determine sample size for the prospective cohort, we assumed a
doubling of the primary endpoint compared to the retrospective cohort
given the prospective ascertainment. Additionally, based on previous
data that acute hemodynamic changes affect clinical HF, we assumed a
left atrial pressure difference of 5 mmHg in those with or without early
incident HF (14+/- 6 mmHg v. 9 mmHg), and with alpha = 0.05 and beta =
0.80, a total of 104 patients was recommended
(https://clincalc.com/stats/samplesize.aspx). (21) Because of the
greater than expected rate of HF, the study was stopped at 100 subjects.
RESULTS
For the retrospective analysis, there were 391 patients who were
included, with a primary endpoint reached in 13 patients (3.3%). When
the group of early incident HF patients was compared to the control
group, univariate correlates to the primary endpoint included longer
procedure time (5:47 v. 4:41 hr, p = 0.002), greater fluid
administration (2406 v 1887 mL, p = 0.015), and preexisting diagnosis of
HF (69% v 39%, p = 0.03). Persistent AF, redo procedure, gender, age,
body mass index, chronic kidney disease, serum creatinine, diabetes
mellitus, and coronary disease were not different in the two groups.
Significantly associated variables were included in a multivariable
model, but no factors remained independently associated with the primary
outcome.