Statistical analysis
Categorical variables are summarized as percentages. Normally
distributed continuous data is expressed as mean ± SD and non-normally
distributed data is expressed as median with interquartile range of
25th and 70th percentiles. For
comparing variables, we used a χ2-test (categorical variables), a t-test
(normally distributed continuous variables) and a Mann-Whitney U test
(non-normal continuous variables). Kappa statistics were used to
calculate the inter-observer variability in the extent and location of
CAD detected in the coronary angiograms. Cumulative hazard and the
survival curves following ICD intervention were analysed with the
Kaplan-Meier survival analysis method and the statistical comparison
using the log-rank test. Cox proportional hazards regression models were
used to determine the predictors of survival. The co-efficients were
expressed as hazard ratios with 95% confidence intervals. P value
<0.05 was considered statistically significant.