Catecholaminergic polymorphic ventricular tachycardia medical therapy

Pharmacologic medical therapies for CPVT include beta blockers, flecainide and verapamil. Beta blockers remain the first-line therapeutic option for all the patients with catecholaminergic polymorphic ventricular tachycardia.

Pharmacologic medical therapies for CPVT include beta blockers, flecainide and verapamil.

• The first-line therapeutic option for patients with CPVT is exercise restriction combined with beta-blockers without intrinsic sympathomimetic activity.^[1]
• Because of the adrenergic nature of arrhythmias in CPVT, non-selective beta-blockers, titrated at the maximum tolerated dose in the absence of contraindications (example, asthma) are considered the most effective pharmacological therapy.
• Indications:
  • All patients with stress-induced ventricular arrhythmias.
  • Silent carriers of a pathogenic mutation, even when they do not exhibit arrhythmias during exercise stress testing since cardiac arrest may occur in them.^[2]
• Drugs used:
  • Nadolol^[3][4]
    • Long-acting, non-selective beta-blocker.
    • Preferred for prophylactic treatment of CPVT.
    • It is considered the most clinically effective choice.
    • Dosage: 1-2 mg/kg per day.
  • Propranolol
    • Long-acting, non-selective beta-blocker.
    • It is also considered an effective medication when Nadolol is unavailable.
    • Dosage: 3-5 mg/kg per day.
• Holter monitoring and exercise stress testing should be repeated periodically throughout beta blocker therapy, to ensure that the heart-rate is in control during exercise.
• Non-compliance and abrupt interruption of beta blockade may cause a rebound effect of catecholamines on the heart, leading to arrhythmic events while on therapy. Thus, it is important to educate and highlight to patients the need to be compliant with therapy.^[5][6]
• Even with appropriate use, beta blockers cannot completely suppress the arrhythmias.
• Recurrent arrhythmias or persistence of complex arrhythmias at exercise stress test may occur in up to one-third of the CPVT patients, with the annual arrhythmic event rate ranging between 11% per year and 3% per year.^[3][7][8]

• Calcium channel blocker.
• Verapamil might be considered as adjunctive therapy for CPVT patients with ongoing ventricular arrhythmias despite therapy with beta blockers.^[9][10]
• However, the long-term efficacy of verapamil is still controversial.

• Flecainide which is best known as a cardiac sodium channel blocker (a Class IC antiarrhythmic) is also found to inhibit the cardiac ryanodine receptor (RyR2. This dual-action makes it an effective medication for CPVT.^[11]
• Indications:^[11][12]
  • Patients with persistent arrhythmias despite beta blocker therapy.
  • Patients with an ICD who continue to have stress-induced ventricular arrhythmias despite beta-blocker therapy.
• Dosage: 100-300 mg/day (1.5-4.5 mg/kg/day).^[6]
• Randomized clinical trials for the long-term efficacy of flecainide are still ongoing.^[13]

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