THE EFFECT OF LEFT VENTRICULAR SENSING ELECTRODE POSITION ON ELECTRICAL DELAY IN CARDIAC RESYNCHRONIZATION THERAPY

Abstract Background Current cardiac resynchronization therapy (CRT) works by pacing the latest activated left ventricular (LV) site. We hypothesized that the greater nonresponse rate of patients with nonspecific intraventricular conduction disturbance (NICD) than with left bundle branch block (LBBB) pattern to CRT might be due, besides less dyssynchrony, to the inability of the current CRT technique, devised to eliminate dyssynchrony caused by LBBB pattern, to eliminate dyssynchrony in some patients with NICD pattern, because their latest activated LV site is far away from that in LBBB. Methods We devised a novel surface ECG method to estimate the approximate location of the latest activated LV site based on the principle that the resultant ST vector of secondary ST segment alterations associated with wide QRS complexes is directed 180o away from the latest activated LV site. By measuring the amplitude and polarity of secondary ST segment alterations in two optional frontal and horizontal plane ECG leads and using a software, we determined the resultant 3D spatial secondary ST vector in 88 patients with LBBB and 57 patients with NICD patterns and heart failure. To validate the ECG method, we also estimated the latest activated LV region by echocardiography using 3D parametric imaging and 2D speckle tracking in 16 LBBB and 13 NICD patients. Patients with NICD pattern were subdivided according to their non-overlapping frontal plane resultant secondary ST vector ranges to NICD-1 (n=35) and NICD-2 (n=22) subgroups. Results The resultant 3D spatial secondary ST vector coordinates in the LBBB group were: (x axis: −0.228 mV, y axis: −0.062 mV, z axis: 0.63 mV); in the NICD-1 and NICD-2 subgroups: (x: 0.154 and 0.198 mV, y: −0.198 and 0.162 mV, z: 0.422 and 0.398 mV respectively). Consequently the latest activated LV sites were located leftward, posterosuperior in the LBBB group, right, posterosuperior in the NICD-1 and right, posteroinferior in the NICD-2 subgroups. The latest activated LV region determined by ECG and echocardiography matched in all patients, except 1. Conclusions The latest activated LV site was at the expected position in the LBBB group, while it was at an almost opposite site in the NICD-2 group [22/57 (39%)]. Thus, one potential reason for the unfavorable response to CRT, occurring in approx. 40% of patients with NICD pattern with a QRS duration of 120–149 ms in randomized studies, is that the current CRT technique using a left posterolateral LV electrode position may not be able to eliminate dyssynchrony in these patients. Funding Acknowledgement Type of funding source: None

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Heart rhythm model for the simulation of electric fields in transesophageal atrial pacing and cardiac resynchronization therapy

Current Directions in Biomedical Engineering ◽

10.1515/cdbme-2018-0105 ◽

2018 ◽

Vol 4 (1) ◽

pp. 443-445

Author(s):

Kerem Göküs ◽

Matthias Heinke ◽

Johannes Hörth

Keyword(s):

Cardiac Resynchronization Therapy ◽

Heart Rhythm ◽

Left Ventricular ◽

Right Atrial ◽

Cardiac Resynchronization ◽

Electrode Position ◽

Atrial Pacing ◽

Far Field ◽

Resynchronization Therapy ◽

Rv Pacing

AbstractElectric field of biventricular (BV) pacing, left ventricular (LV) electrode position and electrical interventricular desynchronization are important parameters for successful cardiac resynchronization therapy (CRT) in patients with heart failure, sinus rhythm and reduced LV ejection fraction. The aim of the study was to evaluate electric pacing field of transesophageal left atrial (LA) pacing and BV pacing with 3D heart rhythm simulation. Bipolar right atrial (RA), right ventricular (RV), LV electrodes and multipolar hemispherical esophageal LA electrodes were modeled with CST (Computer Simulation Technology, Darmstadt). Electric pacing field were simulated with bipolar RA and RV pacing with Solid S (Biotronik) electrode, bipolar LV pacing with Attain 4194 (Medtronic) electrode and bipolar LA pacing with TO8 (Osypka) esophageal electrode. 3D heart rhythm model with esophagus allowed electric pacing field simulation of 4-chamber pacing with bipolar intracardiac RA, RV, LV pacing and bipolar transesophageal LA pacing. The pacing amplitudes were 3V RA pacing amplitude, 50V LA pacing amplitude, 1.5V RV pacing amplitude and 3V LV pacing amplitude with 0.5ms pacing pulse duration. The atrioventricular delay between RA pacing and BV pacing was 140ms atrioventricular pacing delay and simultaneous RV and LV pacing. Electric pacing fields were simulated during the different pacing modes AAI, VVI, DDD and DDD0V. The intracardiac far-field pacing potentials were evaluated with intracardiac electrodes and a distance of 1mm from the electrodes with RA electrode 1.104V, RV electrode 0.703V and LV electrode 1.32V. The transesophageal far-field pacing potential was evaluated with transesophageal electrode and a distance of 10mm from the elelctrode with LA electrode 6.076V. Heart rhythm model simulation with esophagus allows evaluation of electric pacing fields in AAI, VVI, DDD, DDD0V and DDD0D pacing modes. Electric pacing field of RA, RV and LV pacing in combination with LA pacing may additional useful pacing mode in CRT non-responders.

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Technical and electrophysiological aspects of multisite cardiac stimulation through the access of the middle cardiac vein

EP Europace ◽

10.1093/europace/euab116.019 ◽

2021 ◽

Vol 23 (Supplement_3) ◽

Author(s):

A Rosa Filho ◽

AAM Rosa ◽

AW Rosa ◽

JC Souza Neto ◽

LB Cavalcanti ◽

...

Keyword(s):

Cardiac Resynchronization Therapy ◽

Guide Wire ◽

Anatomical Variations ◽

Left Ventricular ◽

Cardiac Resynchronization ◽

Electrode Position ◽

Resynchronization Therapy ◽

Cardiac Stimulation ◽

Funding Sources ◽

Middle Cardiac Vein

Abstract Funding Acknowledgements Type of funding sources: None. Main funding source(s): Alfredo Aurélio Marinho Rosa and Alfredo Aurélio Marinho Rosa Filho Background Heart failure (HF) is a serious, progressive disease, caused by ventricular dysfunction, leading to a worsening in quality and a reduction in life expectancy. Cardiac resynchronization therapy through multisite stimulation has become an important tool in the treatment of advanced HF, however, due to anatomical variations and even the absence of appropriate veins for the insertion of the left ventricular electrode, the access of the middle cardiac vein can be an option for biventricular cardiac stimulation. Objective: To present the technique used to access the middle cardiac vein (MCV) for the implantation of the left ventricular electrode and the results of this multisite stimulation. Material and Method: Between March 2006 and May 2016, 388 patients (PT) underwent biventricular stimulation (BIV) at our service. 276 PT (71.1%), were associated with the cardioverter-defibrillator (ICD), 226 PT (58.2%) were male and their age ranged from 28 to 84 years with an average of 64 years. In this group, in 63 PT (16.2%) the left ventricular electrode was implanted through CMV. The technique initially consists of introducing a deflectable catheter for marking the coronary sinus (SC) via the femoral approach, then the SC approach is performed by puncturing the left subclavian vein, introducing an 8F sheath up to the proximal 1/3, where the VCM venogram is performed by introducing a 0.014 "guide wire and the 5 F bipolar or quadripolar electrode, then defining the best electrode position from the smallest stimulated QRS. Results: In this group of 63 PT, 52 PT (82.5%) responded to cardiac resynchronization therapy. The most frequent cardiopathies involved were ischemic (38%), chagasic (25%), hypertensive (12%) and others (25%). The thresholds varied from 3.5 to 0.5 V, impedance from 600 to 1200 ohms and sensitivity between 10 and 20 mV. There were no complications in the trans or post implant and in 5 PT (7.9%), there was phrenic stimulation. The procedure time varied from 50 to 180 minutes. Conclusion: Multisite stimulation through the access of the middle cardiac vein proved to be a possible alternative, easy to perform and with a high PT index responsive to cardiac resynchronization therapy.

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