Spss version 22

Statistical analysis was performed using SPSS version 22.0. Descriptive statistics were given as counts and percentages for categorical variables; interquartile ranges and median were given for nonparametric continuous variables; standard deviation and mean for parametric continuous variables. Chi-square test was performed for categorical data. Kruskal–Wallis test was used to compare three groups on continuous variables. A P-value of less than 0.05 was considered statistically significant. Kappa statistics were calculated using SPSS version 22.0 to determine the proportion of interobserver agreement beyond that expected by chance. The method for estimating an overall kappa value in cases of multiple observers and categories is based on the work of Landis and Koch. A value of k.1.0 corresponds to complete agreement; 0, no agreement; and less than 0, disagreement. Landis and Koch suggested that a kappa value 0.20 indicates slight agreement; 0.21–0.40, fair agreement; 0.41–0.60, moderate agreement; 0.61–0.80, substantial agreement; and 0.81–1.00, almost perfect agreement (14 (link)).

The data was collected using a structured questionnaire. Data entry and analysis was done on SPSS version 22.0. Categorical variables were expressed as proportion and percentages. Quantitative variables were expressed in mean ± standard deviation and median (interquartile range). Univariate analysis in form of Chi-square test for categorical variable and T test for quantitative variables was done to explore the association of factors with rhythm conversion. To compare median across the groups, Mann-Whitny U test was conducted. Statistical significance was defined at a p value of less than 0.05. Binary logistic regression using Forward Conditional method was applied by including factors from univariate analysis (with p-value <0.20). Independent factors like serum magnesium level at time of Ibutilide injection, serum potassium level at the time of injection, beta blocker usage, and left atrial size were included in the model. ROC curve was plotted using SPSS version 22.0 between serum magnesium level at time of admission, serum magnesium level at time of ibutilide injection and conversion of arrhythmia. The area under curve and cut-off point of magnesium at maximum sensitivity and specificity was determined.