Irbesartan for the Prevention of Atrial Arrhythmias and Cardiac Electrical Remodeling in Patients With Hypertension and Permanent Pacemakers

Inclusion Criteria: * Sinus Node Dysfunction (with or without AV conduction disturbance) * Permanent, atrial or dual-chamber pacemaker implanted \> 2 months before enrollment and with ability to record and store atrial high-rate episodes, frequency of mode switches and to perform non-invasive electrophysiologic testing * History of at least 6 AHRE in the last 6 months (rate \> 220/min, duration of \> 2 minutes * History of prior diagnosis of hypertension and/or treated for hypertension OR two documented BP \> 130/85 (measurements done at least one week apart) Exclusion Criteria: * Permanent or persistent AF or more than 6 episodes of symptomatic paroxysmal AF in the previous 6 months * Documented Cr \>200 umol/L and K+ \>5.2 mmol/L in the previous 3 months * Current treatment with a potassium sparing diuretic, unless serum potassium known to be in the normal range * LV ejection fraction known to be \< 40 % * Moderate or severe mitral regurgitation (3+, 4 +) * Mitral stenosis of more than mild severity * Aortic stenosis with mean gradient of \> 25 mmHg * Angina at rest in the last 2 months, or current CCS Class 3 or 4 angina * Unipolar atrial lead * Previous AV node ablation * P-wave amplitude less than 1.5 mV * Current therapy with an ACE inhibitor, ARB or aldosterone antagonist * Current or planned (within 6 months) with an anti-arrhythmic medication (amiodarone, sotalol, flecainide, propafenone, quinidine, dofetilide