ACUTE DYSFUNCTION OF CHRONIC RESYNCHRONIZATION THERAPY EVALUATED BY B-TYPE NATRIURETIC PEPTIDE

Background: Although B-type natriuretic peptide (BNP) has been adopted in clinical practice, many of BNP pathophysiological properties are still unknown.
Aims: To assess the time required for a BNP change in response to the pacemaker reprogramming from chronic biventricular pacing (BiVP) to the haemodynamically less effective right univentricular pacing (RVP) in humans with homogenous chronic heart failure.
Methods: BNP examination was carried out in 10 patients (age 66.6±6.5 years; left ventricular ejection fraction 23.0±7.9%; QRS duration 168±10 ms) who, despite initial stabilization, remained on chronic cardiac resynchronization therapy (21.4±10.6 months on CRT) in New York Heart Association class III. A series of 8 BNP plasma levels was obtained over a 6-hour period (8:00-14:00 hrs) on each of the consecutive days (D1; D2). After pacemaker switchover (D2 at 10:00 hrs), the RVP was kept until 14:00 hrs.
Results: The reprogramming manoeuvre was followed by an increase in circulating BNP compared to the control day (D1), and first detected after 3 hours of RVP (P=0.043).  
Conclusion: Despite the harmony between the increase in BNP, thought to be induced by a simulated acute CRT failure, and our presumption, a reliable interpretation, at this point, is not definite.