Effect of Right Ventricular Versus Biventricular Pacing on Electrical Remodeling in the Normal Heart

Saba, Samir; Mehdi, Haider; Mathier, Michael A.; Islam, Monzurul; Salama, Guy; London, Barry

doi:10.1161/circep.109.889741

Cited by 17 publications

(13 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…20,21 An article reporting on RV and LV samples showed no significant change in Cx43 and SCN5A expression in RV-paced rabbits (comparable with LBBB) as compared with control rabbits. 22 The present findings on transseptal conduction may explain several hemodynamic aspects of CRT. First of all, several patient studies and data derived from a canine model of dyssynchronous heart failure showed that LV and BiV pacing may have the same hemodynamic benefits.…”

Section: Slow Transseptal Conductionmentioning

confidence: 54%

Transseptal Conduction as an Important Determinant for Cardiac Resynchronization Therapy, as Revealed by Extensive Electrical Mapping in the Dyssynchronous Canine Heart

Strik

Deursen

Middendorp

et al. 2013

Circ: Arrhythmia and Electrophysiology

View full text Add to dashboard Cite

Background-Simple conceptual ideas about cardiac resynchronization therapy assume that biventricular (BiV) pacing results in collision of right and left ventricular (LV) pacing-derived wavefronts. However, this concept is contradicted by the minor reduction in QRS duration usually observed. We investigated the electric mechanisms of cardiac resynchronization therapy by performing detailed electric mapping during extensive pacing protocols in dyssynchronous canine hearts. Methods and Results-Studies were performed in anesthetized dogs with acute left bundle-branch block (LBBB, n=10) and chronic LBBB with tachypacing-induced heart failure (LBBB+HF, n=6). Activation times (AT) were measured using LV endocardial contact and noncontact mapping and epicardial contact mapping. BiV pacing reduced QRS duration by 21±10% in LBBB but only by 5±12% in LBBB+HF hearts. Transseptal impulse conduction was significantly slower in LBBB+HF than in LBBB hearts (67±9 versus 44±16 ms, respectively), and in both groups significantly slower than transmural LV conduction (≈30 ms). In both groups QRS duration and vector and the epicardial AT vector amplitude and angle were significantly different between LV and BiV pacing, whereas the endocardial AT vector was similar. During variation of atrioventricular delay while LV pacing, and ventriculo-ventricular delay while BiV pacing, the optimal hemodynamic effect was achieved when epicardial AT and QRS vectors were minimal and endocardial AT vector indicated LV preexcitation. Conclusions-Due

show abstract

Section: Slow Transseptal Conductionmentioning

confidence: 54%

Transseptal Conduction as an Important Determinant for Cardiac Resynchronization Therapy, as Revealed by Extensive Electrical Mapping in the Dyssynchronous Canine Heart

Strik

Deursen

Middendorp

et al. 2013

Circ: Arrhythmia and Electrophysiology

View full text Add to dashboard Cite

show abstract

“…Anti-Nav1.5 antibody (1:100, Alomone Labs, Jerusalem, Israel) was used to evaluate the Na + channel protein expression. 21 The enzymatic activity was revealed with alkaline phosphatase chemiluminescent substrates (Amresco, Solon, OH, USA) and quantified by densitometry. 10, 14 Band densities were normalized to the density of GAPDH to correct the variations in protein loading, and were quantitatively expressed as arbitrary units (a.u.).…”

Section: Tissue Preparationmentioning

confidence: 99%

Short-Duration Therapeutic Hypothermia Causes Prompt Connexin43 Gap Junction Remodeling in Isolated Rabbit Hearts

Hsieh

Yeh

Lin

et al. 2011

Circ J

View full text Add to dashboard Cite

“…The data support a critical role of CaMKII and its regulation in the remodeling and reverse electrical remodeling of ventricular myocyte electrophysiology by DHF and CRT respectively. 19, 36–38 …”

Section: Discussionmentioning

confidence: 99%

Cardiac Resynchronization Therapy Improves Altered Na Channel Gating in Canine Model of Dyssynchronous Heart Failure

Aiba

Barth

Hesketh

et al. 2013

Circ: Arrhythmia and Electrophysiology

View full text Add to dashboard Cite

Background Slowed Na+ current (INa) decay and enhanced late INa (INa-L) prolong the action potential duration (APD) and contribute to early afterdepolarizations (EADs). Cardiac resynchronization therapy (CRT) shortens APD compared to dyssynchronous heart failure (DHF), however, the role of altered Na+ channel gating in CRT remains unexplored. Methods and Results Adult dogs underwent left-bundle branch ablation and right atrial pacing (200 bpm) for 6 weeks (DHF) or 3 weeks followed by 3 weeks of biventricular pacing at the same rate (CRT). INa and INa-L were measured in left ventricular myocytes from non-failing (NF), DHF and CRT dogs. DHF shifted voltage dependence of INa availability by −3 mV compared to NF, enhanced intermediate inactivation and slowed recovery from inactivation. CRT reversed the DHF-induced voltage shift of availability, partially reversed enhanced intermediate inactivation but did not affect DHF-induced slowed recovery. DHF markedly increased INa-L compared to NF. CRT dramatically reduced DHF-induced enhanced INa-L, abbreviated the APD and suppressed EADs. CRT was associated with a global reduction in phosphorylated CaMKII, which has distinct effects on inactivation of cardiac Na+ channels. In a canine AP model, alterations of INa-L are sufficient to reproduce the effects on APD observed in DHF and CRT myocytes. Conclusions CRT improves DHF-induced alterations of Na+ channel function, especially suppression of INa-L, thus abbreviating the APD and reducing the frequency of EADs. Changes in the levels of phosphorylated CaMKII suggest a molecular pathway for regulation of INa by biventricular pacing of the failing heart.

show abstract

Effect of Right Ventricular Versus Biventricular Pacing on Electrical Remodeling in the Normal Heart

Cited by 17 publications

References 24 publications

Transseptal Conduction as an Important Determinant for Cardiac Resynchronization Therapy, as Revealed by Extensive Electrical Mapping in the Dyssynchronous Canine Heart

Transseptal Conduction as an Important Determinant for Cardiac Resynchronization Therapy, as Revealed by Extensive Electrical Mapping in the Dyssynchronous Canine Heart

Short-Duration Therapeutic Hypothermia Causes Prompt Connexin43 Gap Junction Remodeling in Isolated Rabbit Hearts

Cardiac Resynchronization Therapy Improves Altered Na Channel Gating in Canine Model of Dyssynchronous Heart Failure

Contact Info

Product

Resources

About