Gitelman's syndrome with exercise-induced ventricular tachycardia

Area of Science:

• Cardiology
• Electrophysiology
• Internal Medicine

Background:

• A 62-year-old female presented with palpitations and was diagnosed with a high burden of monofocal ventricular premature contractions (VPCs) and non-sustained ventricular tachycardia (VT).
• The patient exhibited electrolyte abnormalities including hypokalemia, hypomagnesemia, and chloride-resistant metabolic alkalosis, alongside elevated plasma renin and aldosterone, suggesting a potential underlying cause for the arrhythmias.
• Cardiac imaging revealed normal coronary arteries but left ventricular akinesis in the posterolateral wall, indicating myocardial dysfunction.

Observation:

• Despite extensive investigation, VT was not inducible via programmed electrical stimulation, even with isoproterenol administration.
• Intracardiac mapping identified the earliest activation site of the VPCs within the asynergic (akinetic) region of the left ventricle.
• The VPCs shared the same QRS morphology as the non-sustained VT, suggesting a common origin.

Findings:

• Radiofrequency catheter ablation (RF-CA) targeting the identified earliest activation site in the left ventricular asynergy area was performed.
• The RF-CA procedure completely eliminated the VPCs without any reported complications.
• The patient remained asymptomatic with no documented VT during a 6-month follow-up period.

Implications:

• This case highlights the efficacy of RF-CA in treating refractory ventricular arrhythmias originating from myocardial scar or dysfunction.
• Targeting arrhythmias based on intracardiac mapping in asynergic areas can be a successful strategy when standard induction protocols fail.
• Accurate localization and ablation of the arrhythmogenic substrate are crucial for long-term freedom from ventricular arrhythmias.