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Left ventricular septal pacing (LVSP) and left bundle branch pacing (LBBP) have been introduced to maintain or correct interventricular and intraventricular (dys)synchrony. LVSP is hypothesised to produce a fairly physiological sequence of activation, since in the left ventricle (LV) the working myocardium is activated first at the LV endocardium i...
Context in source publication
Context 1
... physiological circumstances, left ventricular (LV) activation is started from the left bundle branch from three endocardial areas ( Figure 1): an area high on the anterior paraseptal wall just below the attachment of the mitral valve; a central area on the left surface of the interventricular septum (IVS); and the posterior paraseptal area at about one-third of the distance from apex to base. In the IVS, activation proceeds from left to right and in an apical-basal direction. ...
Citations
... Although LVSP has a longer LVAT in the absence of left bundle capture, the LV activation is more likely to be completed before the RV, mitigating the electrical dyssynchrony of the LV lateral wall. 12,22 Based on these findings, LVSP seems to have acceptable and comparable outcomes to LBBP. Although, currently, LBBP is a desirable procedure endpoint, we could consider LVSP as a sufficient procedure endpoint if larger or more studies support this finding. ...
Background
The outcomes of left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) in patients with heart failure remain to be learned.
Objective
The objective of this study was to assess the echocardiographic and clinical outcomes of LBBP, LVSP, and deep septal pacing (DSP).
Methods
This retrospective study included patients who met the criteria for cardiac resynchronization therapy (CRT) and underwent attempted LBBP in 5 Mayo centers. Clinical, electrocardiographic, and echocardiographic data were collected at baseline and follow-up.
Results
A total of 91 consecutive patients were included in the study. A total of 52 patients had LBBP, 25 had LVSP, and 14 had DSP. The median follow-up duration was 307 (interquartile range 208, 508) days. There was significant left ventricular ejection fraction (LVEF) improvement in the LBBP and LVSP groups (from 35.9 ± 8.5% to 46.9 ± 10.0%, P < .001 in the LBBP group; from 33.1 ± 7.5% to 41.8 ± 10.8%, P < .001 in the LVSP group) but not in the DSP group. A unipolar paced right bundle branch block morphology during the procedure in lead V1 was associated with higher odds of CRT response. There was no significant difference in heart failure hospitalization and all-cause deaths between the LBBP and LVSP groups. The rate of heart failure hospitalization and all-cause deaths were increased in the DSP group compared with the LBBP group (hazard ratio 5.10, 95% confidence interval 1.14–22.78, P = .033; and hazard ratio 7.83, 95% confidence interval 1.38–44.32, P = .020, respectively).
Conclusion
In patients undergoing CRT, LVSP had comparable CRT outcomes compared with LBBP.
... However, there is considerable debate around this, with some authors suggesting that stimulation of the left ventricular endocardium alone may be sufficient. 21 For this study, our goal was to capture the conduction system, but comparing this to left ventricular septal myocardial capture alone would be a very interesting and valuable future study. ...
Aims:
Left bundle branch area pacing (LBBAP) is a promising method for delivering cardiac resynchronization therapy (CRT), but its relative physiological effectiveness compared with His bundle pacing (HBP) is unknown. We conducted a within-patient comparison of HBP, LBBAP, and biventricular pacing (BVP).
Methods and results:
Patients referred for CRT were recruited. We assessed electrical response using non-invasive mapping, and acute haemodynamic response using a high-precision haemodynamic protocol. Nineteen patients were recruited: 14 male, mean LVEF of 30%. Twelve had time for BVP measurements. All three modalities reduced total ventricular activation time (TVAT), (ΔTVATHBP -43 ± 14 ms and ΔTVATLBBAP -35 ± 20 ms vs. ΔTVATBVP -19 ± 30 ms, P = 0.03 and P = 0.1, respectively). HBP produced a significantly greater reduction in TVAT compared with LBBAP in all 19 patients (-46 ± 15 ms, -36 ± 17 ms, P = 0.03). His bundle pacing and LBBAP reduced left ventricular activation time (LVAT) more than BVP (ΔLVATHBP -43 ± 16 ms, P < 0.01 vs. BVP, ΔLVATLBBAP -45 ± 17 ms, P < 0.01 vs. BVP, ΔLVATBVP -13 ± 36 ms), with no difference between HBP and LBBAP (P = 0.65). Acute systolic blood pressure was increased by all three modalities. In the 12 with BVP, greater improvement was seen with HBP and LBBAP (6.4 ± 3.8 mmHg BVP, 8.1 ± 3.8 mmHg HBP, P = 0.02 vs. BVP and 8.4 ± 8.2 mmHg for LBBAP, P = 0.3 vs. BVP), with no difference between HBP and LBBAP (P = 0.8).
Conclusion:
HBP delivered better ventricular resynchronization than LBBAP because right ventricular activation was slower during LBBAP. But LBBAP was not inferior to HBP with respect to LV electrical resynchronization and acute haemodynamic response.
... The initial results of prospective observational studies on LBBAP are encouraging, with LBBAP lead implantation success ranging from 80% to 97%, and tremendous expectations are reposted in LBBAP for achieving resynchronization therapy in patients with HF and LBBB (Huang et al., 2020;Heckman et al., 2021;Jastrzębski et al., 2022a;Grieco et al., 2022). A seminal study by Huang and colleagues reported a high LBBAP success rate (97%) as a first-line strategy among 63 patients with LBBB and non-ischemic cardiomyopathy (Huang et al., 2020). ...
Biventricular pacing (BVP) is the established treatment to perform cardiac resynchronization therapy (CRT) in patients with heart failure (HF) and left bundle branch block (LBBB). However, BVP is an unnatural pacing modality still conditioned by the high percentage of non-responders and coronary sinus anatomy. Conduction system pacing (CSP)—His bundle pacing (HBP) and Left bundle branch area pacing (LBBAP)- upcomes as the physiological alternative to BVP in the quest for the optimal CRT. CSP showed promising results in terms of better electro-mechanical ventricular synchronization compared to BVP. However, only a few randomized control trials are currently available, and technical challenges, along with the lack of information on long-term clinical outcomes, limit the establishment of a primary role for CSP over conventional BVP in CRT candidates. This review provides a comprehensive literature revision of potential applications of CSP for CRT in diverse clinical scenarios, underlining the current controversies and prospects of this technique.
... Az elkülönítésben a felszíni EKG V6 elvezetésében mért, R-hullám csúcsának megjelenéséig eltelt idő (V6 R wave peak time) segít. LBBP esetén a V6RWPT rövidebb, mint LVSP esetén (34,35). ...
Hagyományos pacemakerkezelésben részesülő betegek balkamra-funkciója a tartós jobb kamrai ingerlés következtében kialakuló elektromechanikai diszszinkrónia miatt romolhat, amelyet pacemaker indukálta cardiomyopathiának nevezünk. A tradicionális kardiális reszinkronizációs kezelés a betegek egy részében nem javítja a prognózist, vagy elvégzésének technikai akadálya lehet. Ezen problémák miatt került előtérbe a fiziológiás ingerületvezetőrendszer-ingerlés (FIRI), amely fiziológiás kamrai aktivációt biztosíthat. A FIRI megvalósítható a His-köteg direkt ingerlésével (HBP), és bal Tawara-szár-régió stimulálásával (LBBAP). Az aktuális nemzetközi irodalmi nómenklatúra a bal Tawara-szár területi ingerlésen (LBBAP) belül különíti el a bal Tawara-szár-ingerlést (LBBP) és a bal kamrai szeptum endokardiális ingerlését (LVSP). Az eddigi tanulmányok biztató eredményei miatt a FIRI megjelent az Európai Kardiológiai Társaság (ESC) aktuális ajánlásaiban, ugyanakkor az indikációk bővülése csak a hatékonyságukat ténylegesen igazoló nagy esetszámú randomizált vizsgálatok eredményeit követően várható.
... The exact mechanism of RV activation during LBBAP has not been elucidated, although retrograde invasion of the conduction system is suggested (32). Irrespective of the exact mechanism, RV activation during LBBAP is delayed compared to LV activation (33,34). This delayed RV activation is characterized by an RBBB pattern on the ECG, which is considered one of the hallmarks of successful LBBAP (17). ...
Background:
Left bundle branch area pacing (LBBAP) induces delayed RV activation and is thought to be harmless, since the electrocardiographic signature is reminiscent to native RBBB. However, to what extent the delayed RV activation during LBBAP truly resembles that of native RBBB remains unexplored.
Methods:
This study included patients with incomplete RBBB (iRBBB), complete RBBB (cRBBB) and patients who underwent LBBAP. Global and right ventricular activation times were estimated by QRS duration and R wave peak time in lead V1 (V1RWPT) respectively. Delayed RV activation was further characterized by duration, amplitude and area of the terminal R wave in V1.
Results:
In patients with LBBAP (n = 86), QRS duration [120 ms (116, 132)] was longer compared to iRBBB patients (n = 422): 104 ms (98, 110), p < 0.001, but shorter compared to cRBBB (n = 223): 138 ms (130, 152), p < 0.001. V1RWPT during LBBAP [84 ms (72, 92)] was longer compared to iRBBB [74 ms (68, 80), p < 0.001], but shorter than cRBBB [96 ms (86, 108), p < 0.001]. LBBAP resulted in V1 R' durations [42 ms (28, 55)] comparable to iRBBB [42 ms (35, 49), p = 0.49] but shorter than in cRBBB [81 ms (68, 91), p < 0.001]. During LBBAP, the amplitude and area of the V1 R' wave were more comparable with iRBBB than cRBBB. V1RWPT during LBBAP was determined by baseline conduction disease, but not by LBBAP capture type.
Conclusion:
LBBAP-induced delayed RV activation electrocardiographically most closely mirrors the delayed RV activation as seen with incomplete rather than complete RBBB.
... The sequence of electrical activation in the normal heart -as well as in the paced heart -is elaborated on in a related article in this volume. 12 Like in any muscle, contraction of cardiac muscle cells is evoked by an action potential. The action potential triggers calcium influx that subsequently initiates calcium-induced calcium release. ...
Abnormal electrical activation of the ventricles creates abnormalities in cardiac mechanics. Local contraction patterns, as reflected by strain, are not only out of phase, but also show opposing length changes in early and late activated regions. Consequently, the efficiency of cardiac pump function (the amount of stroke work generated by a unit of oxygen consumed), is approximately 30% lower in dyssynchronous than in synchronous hearts. Maintaining good cardiac efficiency appears important for long-term outcomes. Biventricular, left ventricular septal, His bundle and left bundle branch pacing may minimise the amount of pacing-induced dyssynchrony and efficiency loss when compared to conventional right ventricular pacing. An extensive animal study indicates maintenance of mechanical synchrony and efficiency during left ventricular septal pacing and data from a few clinical studies support the idea that this is also the case for left bundle branch pacing and His bundle pacing. This review discusses electro-mechanics and mechano-energetics under the various paced conditions and provides suggestions for future research.
