Here is the design of a clinical trial:

Official Title: Isthmus Guided vs Anatomical Linear Ablation in the Treatment of Scar Related Atrial Tachycardia

Included conditions:
- Atrial Tachycardia

Study Armgroups:
- {'label': 'Isthmus targeted approach using Ripple Mapping', 'type': 'ACTIVE_COMPARATOR', 'description': 'Intervention: Isthmus targeted approach using Ripple Mapping catheter ablation of atrial tachycardia.', 'interventionNames': ['Procedure: Catheter ablation of atrial tachycardia: Ripple Mapping guided.']}
- {'label': 'Conventional Mapping', 'type': 'ACTIVE_COMPARATOR', 'description': 'Intervention: conventional catheter ablation of atrial tachycardia.', 'interventionNames': ['Procedure: Catheter ablation of atrial tachycardia: Conventional mapping guided.']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Catheter ablation of atrial tachycardia: Ripple Mapping guided.', 'description': 'Ripple Mapping is used to map the atrial tachycardia mechanism. Using the scar thresholding technique the Ripple Map is interpreted and catheter ablation directed to the site of the heart identified as putative to the arrhythmia mechanism. All ablation lesions are confirmed to have conduction block across them using Ripple Mapping. This can include lesions created at previous ablation procedures.', 'armGroupLabels': ['Isthmus targeted approach using Ripple Mapping']}
- {'type': 'PROCEDURE', 'name': 'Catheter ablation of atrial tachycardia: Conventional mapping guided.', 'description': 'Conventional activation mapping is used to map the atrial tachycardia mechanism. The resultant (activation) map is interpreted and ablation directed to the site of the heart identified as putative to the arrhythmia mechanism. All ablation lesions are confirmed to have conduction block across them using conventional mapping. This can include lesions created at previous ablation procedures.', 'armGroupLabels': ['Conventional Mapping']}

Primary Outcomes:
- {'measure': 'Atrial arrhythmia recurrence', 'description': 'Any confirmed episode of atrial arrhythmia (\\>30 seconds on Holter or 12 lead ECG) occurring in the 12 months after catheter ablation.', 'timeFrame': '12 months'}

Please estimate the sample size based on the assumption: 
90% power, alpha value of 0.05, 10% non-completion rate, 10% loss to follow-up rate.
Sample size calculation
        The sample size for this study is based on previous evidence published by our group. In a non-randomised, prospective study comparing ripple mappingâguided ablation to conventional mappingâguided ablation, the diagnostic accuracy was 90% and 65% respectively [10]. A similar effect size was also seen in a randomised prospective study (Ripple-AT Study), showing acute success was 90.5% and 70.7% respectively. In order to detect a difference between arms with 90% power and an alpha value of 0.05, at least 80 patients would be needed to be randomised to each treatment arm. Accounting for potential non-completion of protocol (10%) and loss to follow-up (10%), a minimum of 200 patients will need to be enrolled. Power calculations were performed using the G*Power software (University of Dusseldorf).