Comparison And Application Of The Pacing Parameters Of Quadripolar And Traditional Left Ventricular Leads

Objectives:To investigate the application value of quadripolar left ventricular(LV)leads and their potential capability of optimizing cardiac resynchronization therapy(CRT)effect by comparing quadripolar and traditional unipolar or bipolar LV leads parameters.Methods: Eighteen patients with heart failure(HF)who received CRT device implantation with a LV quadripolar lead(St.Jude Medical)at General Hospital of Shenyang Military Region from January 2014 to December 2015 were enrolled in this study.All patients underwent guideline-directed medical treatment.Inclusion criteria were as follow:(1)the New York Heart Association(NYHA)functional class was II?III or ambulatory IV;(2)left bundle branch block(LBBB)with wide QRS complex?120 ms,or complete atrioventricular block;(3)left ventricular ejection fraction(LVEF)<35%.Pacing parameters analyzed and compared in the study included LV pacing site,phrenic nerve stimulation(PNS),LV capture threshold,LV electrical delay(QLV),left and right ventricular conduction time(RLV)and the separation of the LV and right ventricular lead.The step by step principle of selecting one pacing vector of the ten LV vectors as optimized CRT configurationwas(1)absence of PNS;(2)appropriate capture threshold;(3)avoiding apical position;(4)maximal QLV;(5)maximal RV-to-LV lead separation.Results: Among all the eighteen CRT patients(61±8(47-75)years,11 men),twelve patients were diagnosed as dilated cardiomyopathy and six patients were diagnosed as ischemic cardiomyopathy.Three patients were biventricular pacing for complete atrioventricular block.The QRS widths of fifteen patients were 167±27(120-200)ms;LVEF:0.28±0.06(0.15-0.35);left ventricular end-systolic volume(LVESV): 231±82(134-459)ml;6-minute-walk test: 334±92(157-493)m.The rate of apical pacing were lowered in quadripolar versus traditional bipolar and unipolar-simulated configurations: 5.6%(1/18),33.3%(6/18),50%(9/18).Compared with unipolar simulated configuration,the rate of apical pacing in quadripolar was decreased by 44.4%,P =0.003;when compared with bipolar-simulated configurations,it was decreased by 27.7%,P =0.035.PNS was found in quadripolar,bipolar and unipolar configurations with a rate of 5.6%(1/18),11.1%(2/18),27.8%(5/18).There was no prevalence of PNS requiring lead revision among quadripolar leads in eighteen patients.All the eighteen patients avoided the high pacing thresholds.The high thresholds pacing was 11.1%(2/18)in unipolar-simulated configurations.Every patient who underwent CRT with a LV quadripolar lead have four QLV data,being arranged in ascending order.QLV intervals of each group were 115±37ms?125±40ms?130±39ms and 140±43ms.The significantly statistical differences exist between the two groups of two(P <0.01).Based on the absence of PNS,appropriate capture threshold and non-apical position pacing,ten of fifteen patients(10/15,67%)paced in the individually optimized QLV interval among the four QLV intervals,LV pacing site located in maximize QLV interval.Every patient who underwent CRT with a LV quadripolar lead has four RV-to-LV leads separation,being arrange in ascending order RV-to-LV leads separations of each group were 73±20mm?82±20 mm?86±19mm and 94±18mm.The significantly statistical differences exist between the two groups of two(P <0.01),Based on absence of PNS,appropriate capture threshold,non-apical position pacing and maximal QLV interval,one patient paced in the individually optimized RV-to-LV leads separation among the four separations,LV pacing site located in maximize RV-to-LV leads separation.In this study,two patients chosen D1 as pacing cathode ring,three patients chosen M2 as pacing cathode ring,four patients chosen M3 as pacing cathode ring and nine patients chosen P4 as pacing cathode ring.The LV pacing sites of thirteen patients(13/18,72.2%)were unique which traditional unipolar and bipolar-simulated leads cannot have.Conclusions: Quadripolar left ventricular(LV)leads offer ten available bipolar pacing configurations for solving the PNS requiring lead revision and high pacing thresholds problems effectively.Compared with traditionalleads,the rate of apical pacing was decreased.QLV,RLV and the separation of the LV and right ventricular leads do have statistical differences,which provides potential value and application in CRT optimized configuration.