Medical devices for determining catheter tip location; medical devices for monitoring and processing electrocardiogram (ECG) signals for determining catheter tip location; catheter tip location kits and accessories, containing, namely, a catheter connector and ECG cable for use in determining catheter tip location; catheter electrodes; catheter interface modules and cables; patient monitors for displaying catheter tip location; patient monitors for displaying and processing electrocardiogram (ECG) signals for determining catheter tip location; instruments for analyzing and diagnosing cardiac and vascular ailments.