Left ventricular lead implantation at a phrenic stimulation site is safe and effective.
OBJECTIVE
Phrenic stimulation (PS) is a major limiting factor for both left ventricular (LV) lead placement and cardiac resynchronization therapy (CRT) delivery. We have developed a protocol allowing for LV lead implantation at a PS site based on specific criteria regarding phrenic and LV acute capture thresholds. The present study examined long-term outcomes in patients treated using this protocol.


RESULTS
A total of 211 consecutive patients underwent CRT device implantation. The procedure was successful in 201 patients. Leads were implanted at a PS site in 27 patients (PS patients) and a non-PS site in 174 patients (non-PS patients). Left ventricular leads were placed at a PS site only on the following conditions: no PS at ≤3.5 V/0.5 ms, LV threshold ≤1.5 V, and a PS/LV threshold ratio >4. The mean PS threshold decreased (5.1 ± 1.6 vs. 2.8 ± 1.6 V, P < 0.001) and the mean LV threshold remained stable (1.0 ± 0.7 vs. 0.9 ± 0.8 V, P = 0.6) in PS patients over the 16 ± 9 month follow-up. Only one PS patient experienced non-reprogrammable PS and required a re-operation. Seven PS patients required very low LV channel output programming without the usual safety margin of twice the LV threshold amplitude or three times the pulse width. However, 100% LV capture was shown in those patients during daily activity. Non-reprogrammable PS occurred in 2 of the 174 non-PS patients.


CONCLUSIONS
Our strategy for LV lead implantation at a PS site was found to result in long-term safe and effective outcomes.
First Department of Cardiology and Hypertension, University Hospital, ul. Kopernika 17, 31-501 Krakow, Poland. mcjastrz@cyf-kr.edu.pl
Marek
M
Jastrzebski
Bogumila
B
Bacior
Wiktoria
W
Wojciechowska
Danuta
D
Czarnecka
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D058406:Cardiac Resynchronization Therapy / Q000379:methods; D058409:Cardiac Resynchronization Therapy Devices / Q000009:adverse effects*; D004562:Electrocardiography; D004567:Electrodes, Implanted / Q000009:adverse effects*; D005260:Female; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010791:Phrenic Nerve / Q000502:physiology*; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*