The purpose of this study is to demonstrate the advantage of using a gold alloy tip electrode over a platinum/iridium alloy tip electrode in ablation of the cavotricuspid isthmus in patients with atrial flutter.

Transvenous catheter ablation has become the therapy of choice for patients with recurring, isthmus-dependent right atrial flutter. Achieving bidirectional conduction block in the cavotricuspid isthmus is decisive for both acute and long-term therapy success and essentially depends on the selected ablation method and the lesion size. By using an 8 mm tip electrode instead of a conventional 4 mm electrode, deeper lesions can be made, thus significantly reducing the required number of energy applications for achieving a bidirectional conduction block. Experimental studies have proven that using an ablation electrode made of gold alloy allows the creation of deeper lesions than with conventional platinum-iridium electrodes. Due to the greater heat conductivity of the gold alloy as opposed to platinum-iridium, the cooling of the ablation electrode is improved and more electric energy can be transmitted to the tissue at identical temperatures.

The combination of both technologies in the form of an 8 mm-long gold electrode anticipates that the lesion depth required for an isthmus block can be achieved more quickly in comparison to the platinum-iridium electrode.

Inclusion Criteria:

• At least one electrocardiogram (ECG)-documented (can be older than 3 months), symptomatic, typical atrial flutter episode with either negative, sawtooth-shaped P-waves in leads II, III, and augmented voltage foot (aVF), or positive P-waves in leads II, III, and aVF
• At least one persistent, typical atrial flutter episode of over 2 hours that has been documented in the history in the patient file and/or ECG
• Signed informed consent form

Exclusion Criteria:

• Patient has recently undergone isthmus ablation
• Acute coronary syndrome or myocardial infarction within the last 3 months
• Acute reversible causes for atrial flutter (e.g. acute myocarditis)
• Severe cardiac valvular defects
• Tricuspid valve replacement
• Atrial septum defect
• Cardiovascular surgery scheduled within the next 6 months
• Unstable medication in the last 7 days before study inclusion
• New York Heart Association (NYHA) class IV
• Women who are breastfeeding
• Pregnancy
• Abuse of drugs or alcohol
• Patient is unable to participate in follow-up examinations
• The patient has only partial legal competence
• Participation in another clinical study
• The ablation procedure presents an above average risk to the patient as compared to the normal patient group (must be noted by the physician on the appropriate form).
• Right atrial thrombus

Late Exclusion Criteria:

• Patient included by accident
• Premature termination of the ablation procedure
• Atrial flutter not dependent on the posterior isthmus
• No conduction at the posterior isthmus before ablation