OBJECTIVE
To analyze the effects of antiarrhythmic drugs on parameters of dual-chamber pacemakers in patients with paroxysmal atrial fibrillation (AF) and sick sinus syndrome.
MATERIAL AND METHODS
The study included 203 patients (31.5% men, mean age 77.2±8.9 years) with paroxysmal AF and de novo implanted dual-chamber pacemaker. Patients received antiarrhythmic drugs class Ic, II and III. All patients underwent ECG, echocardiography, 24-hour ECG monitoring and 6-minute walk test (SMWT); 3, 6 and 12 months later — pacemaker check and SMWT. We assessed the influence of these drugs on frequent switching of the right ventricular electrode and chronotropic incompetence. Patients with frequent switching of the right ventricular electrode were divided into two groups: group 1 — 52 ones with heart failure (HF) progression, group 2 — 47 patients without HF progression. Statistical analysis implied Fisher’s Z-test. Differences were significant at p-value <0.05.
RESULTS
Frequent switching of the right ventricular electrode was detected in 116 cases. Activation of corrective algorithms was effective in 23 people. In other 93 cases, we attempted to reduce this effect via correction of antiarrhythmic therapy. As a result, switching of the right ventricular electrode was minimized after reducing the dose or withdrawal of beta-blockers, as well as withdrawal of sotalol or propafenone in 55 (47%) cases. At the same time, dose reduction or withdrawal of allapinine, etacizine or amiodarone had no effect in any case. There were significant between-group difference after correction of therapy with/without beta-blocking effect (p<0.001). More active progression of heart failure NYHA class was found in patients with right ventricular dilatation and severe tricuspid regurgitation (p<0.05). Chronotropic incompetence was detected in 57 (28%) cases.
CONCLUSION
Patients with tachycardia-bradycardia syndrome need to check pacemaker and SMWT data after appointment or correction of antiarrhythmic therapy for timely detection and correction of frequent switching of the right ventricular electrode and chronotropic incompetence. In case of frequent switching of the right ventricular electrode, reducing the dose or withdrawal of beta-blockers, as well as replacing sotalol and propafenone with beta-blocking effect with other drugs of appropriate classes are advisable. Heart failure aggravation following frequent switching of the right ventricular electrode develops especially rapidly in patients with right ventricular dilatation and moderate-to-severe tricuspid regurgitation.
