Right Ventricular Apical Pacing and Mitral Regurgitation

Right ventricular apical pacing and mitral regurgitation

Right ventricular apical pacing may sometimes cause mitral regurgitation or worsen a pre-existing mitral regurgitation. Several mechanisms have been considered for this phenomenon:

  1. Right ventricular apical pacing alters the sequence of ventricular activation and causes interventricular and intraventricular dyssynchrony, which can cause mitral regurgitation or worsen a pre-existing mitral regurgitation
  2. Another mechanism considered is an altered papillary muscle function leading to mitral regurgitation.
  3. A third mechanism is pacing induced cardiomyopathy producing left ventricular dilatation and annular dilatation, causing mitral regurgitation.
  4. Left ventricular dilatation and annular dilatation can also contribute to mitral regurgitation, though this may be secondary to the mechanisms discussed above.

In contrast to this, biventricular pacing may improve mitral regurgitation by opposing the above negative effects. In a case report, a patient who had undergone atrioventricular node ablation and dual chamber pacemaker implantation, later developed decompensated heart failure [1]. Initally it was found that mode switch was off and the pacemaker was tracking the high atrial rate. Mode switch was switched on.

There was only slight improvement, with left ventricular ejection fraction around 35% with severe mitral regurgitation. It was decided to upgrade to a biventricular pacing system. Two months post upgrade, left ventricular ejection fraction came up to 40% and mitral regurgitation was only mild to moderate. Patient did not have further recurrent bouts of heart failure.

Upgrading to cardiac resynchronization therapy has been proven to be beneficial in patients with worsening of mitral regurgitation from right ventricular pacing induced dyssynchrony in those with and without ischemic heart disease [1].

Reference

  1. Christopher V Desimone, Vuyisile T Nkomo, Daniel C Desimone, Lawrence R Keenan, Maurice Enriquez-Sarano, Samuel J Asirvatham. An Approach to the Stepwise Management of Severe Mitral Regurgitation With Optimal Cardiac Pacemaker Function. Indian Pacing Electrophysiol J. 2014 Mar 12;14(2):75-8.