June 8, 2011Open Access
View Full PaperManagement of Phrenic Stimulation in CRT Patients over the Long Term: Still an Unmet Need ?
Key Result
Detectable phrenic stimulation at follow-up did not significantly affect objective echocardiographic response rates (76% vs 74% in patients without PS, P=NS).
Study Design
Type
Cohort (n=211)
Structured PICO
Does a phrenic stimulation management strategy allow effective CRT delivery and LV reverse remodeling in patients with PS at the LV target site?
P
Population
211 consecutive patients receiving a CRT device despite phrenic stimulation at the LV target site, followed for a median of 34.9 months.
E
Exposure
Phrenic stimulation management strategy (cathode and pacing vector reprogramming, LV output adjustment) aimed at keeping the target LV implantation site.
C
Comparator
Patients without detectable phrenic stimulation at follow-up (n=160).
O
Outcome
LV reverse remodeling assessed by echocardiography and phrenic stimulation symptoms at follow-up.surrogate
Main Result
Absolute Event Rate: 76% vs 74%
p-value: p=NS
Abstract
BACKGROUND: Phrenic stimulation (PS) may cause intolerable symptoms and prevent CRT delivery in 2-5% of patients. We sought to ensure effective cardiac resynchronization therapy (CRT) delivery by management of PS at the left ventricular (LV) target site. METHODS AND RESULTS: Two hundred and eleven consecutive patients received a CRT device despite PS occurrence at the LV target site at implantation, when a PS-LV difference >2V was achieved by LV stimulation programming (cathode, pacing vector). PS management strategy both at implantation and at follow-up (FU) aimed to keep the target LV implantation site. LV reverse remodeling was assessed by echocardiography before implantation and at follow-up. LV lead placement was lateral/posterolateral in all the 211 patients; 51 of 211 had detectable PS at FU, 26 of 211 (12.3%) were symptomatic. Symptoms occurred more frequently when PS-LV difference was 3V is achieved. Further improvement in lead manufacturing and pacing electronics are awaited to meet this clinical need.