Characteristics and proposed mechanisms of QRS morphology observed during the left bundle branch pacing procedure

Verapamil-sensitive fascicular ventricular tachycardia (VT) is the most common form of idiopathic left VT. According to the QRS morphology and the successful ablation site, left fascicular VT can be classified into three subgroups: left posterior fascicular VT, whose QRS morphology shows right bundle branch block (RBBB) configuration and superior axis (common form); left anterior fascicular VT, whose QRS morphology shows RBBB configuration and right-axis deviation (uncommon form), and upper septal fascicular VT, whose QRS morphology shows narrow QRS configuration and normal or right-axis deviation (rare form). Posterior and anterior fascicular VT can be successfully ablated at the posterior or anterior mid-septum with a diastolic Purkinje potential during VT or at the VT exit site with a fused pre-systolic Purkinje potential. Upper septal fascicular VT can also be ablated at the site with diastolic Purkinje potential at the upper septum. Recognition of the heterogeneity of this VT and its unique characteristics should facilitate appropriate diagnosis and therapy.

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Comparing Ventricular Synchrony in Left Bundle Branch and Left Ventricular Septal Pacing in Pacemaker Patients

Journal of Clinical Medicine ◽

10.3390/jcm10040822 ◽

2021 ◽

Vol 10 (4) ◽

pp. 822

Author(s):

Luuk I.B. Heckman ◽

Justin G.L.M. Luermans ◽

Karol Curila ◽

Antonius M.W. Van Stipdonk ◽

Sjoerd Westra ◽

...

Keyword(s):

Left Ventricular ◽

Activation Time ◽

Ventricular Synchrony ◽

Septal Pacing ◽

Ventricular Activation ◽

Qrs Morphology ◽

Conversion Matrix ◽

Qrs Duration ◽

The Right ◽

Electrophysiological Effects

Background: Left bundle branch area pacing (LBBAP) has recently been introduced as a novel physiological pacing strategy. Within LBBAP, distinction is made between left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP, no left bundle capture). Objective: To investigate acute electrophysiological effects of LBBP and LVSP as compared to intrinsic ventricular conduction. Methods: Fifty patients with normal cardiac function and pacemaker indication for bradycardia underwent LBBAP. Electrocardiography (ECG) characteristics were evaluated during pacing at various depths within the septum: starting at the right ventricular (RV) side of the septum: the last position with QS morphology, the first position with r’ morphology, LVSP and—in patients where left bundle branch (LBB) capture was achieved—LBBP. From the ECG’s QRS duration and QRS morphology in lead V1, the stimulus- left ventricular activation time left ventricular activation time (LVAT) interval were measured. After conversion of the ECG into vectorcardiogram (VCG) (Kors conversion matrix), QRS area and QRS vector in transverse plane (Azimuth) were determined. Results: QRS area significantly decreased from 82 ± 29 µVs during RV septal pacing (RVSP) to 46 ± 12 µVs during LVSP. In the subgroup where LBB capture was achieved (n = 31), QRS area significantly decreased from 46 ± 17 µVs during LVSP to 38 ± 15 µVs during LBBP, while LVAT was not significantly different between LVSP and LBBP. In patients with normal ventricular activation and narrow QRS, QRS area during LBBP was not significantly different from that during intrinsic activation (37 ± 16 vs. 35 ± 19 µVs, respectively). The Azimuth significantly changed from RVSP (−46 ± 33°) to LVSP (19 ± 16°) and LBBP (−22 ± 14°). The Azimuth during both LVSP and LBBP were not significantly different from normal ventricular activation. QRS area and LVAT correlated moderately (Spearman’s R = 0.58). Conclusions: ECG and VCG indices demonstrate that both LVSP and LBBP improve ventricular dyssynchrony considerably as compared to RVSP, to values close to normal ventricular activation. LBBP seems to result in a small, but significant, improvement in ventricular synchrony as compared to LVSP.

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A28-5 Assessment of rhythm discrimination by QRS morphology analysis in single and dual chamber cardioverter defibrillators

EP Europace ◽

10.1016/s1099-5129(03)91667-9 ◽

2003 ◽

Vol 4 ◽

pp. B43

Author(s):

G BORIANI

Keyword(s):

Dual Chamber ◽

Morphology Analysis ◽

Qrs Morphology ◽

Cardioverter Defibrillators

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Automatic QRS morphology template update leads to inappropriate therapy inhibition in a single-chamber ICD

Heart Rhythm ◽

10.1016/j.hrthm.2005.02.922 ◽

2005 ◽

Vol 2 (5) ◽

pp. S293 ◽

Cited By ~ 1

Author(s):

Heather M. Ross ◽

Edward P. Gerstenfeld ◽

Henry H. Hsia ◽

Dusan Z. Kocovic

Keyword(s):

Inappropriate Therapy ◽

Single Chamber ◽

Template Update ◽

Qrs Morphology

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Sudden Modification in QRS Morphology During Entrainment of Ventricular Tachycardia: What Is the Mechanism?

Journal of Cardiovascular Electrophysiology ◽

10.1111/j.1540-8167.2011.02218.x ◽

2011 ◽

Vol 23 (7) ◽

pp. 794-796 ◽

Cited By ~ 1

Author(s):

PHILIPPE MAURY ◽

ALEXANDRE DUPARC ◽

PIERRE MONDOLY ◽

ANNE ROLLIN

Keyword(s):

Ventricular Tachycardia ◽

Qrs Morphology

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Two LBBB-Like Tachycardias with Identical QRS Morphology: What Is the Mechanism?

Journal of Cardiovascular Electrophysiology ◽

10.1111/j.1540-8167.2006.00500.x ◽

2006 ◽

Vol 17 (9) ◽

pp. 1036-1039 ◽

Cited By ~ 3

Author(s):

RONG BAI ◽

EDUARDO B. STERNICK ◽

WEE S. TEO ◽

HEIN J.J. WELLENS

Keyword(s):

Qrs Morphology

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Purkinje fiber trigger for ventricular tachycardia: Local exit block with ablation leading to change in QRS morphology and difficulty with mapping

Heart Rhythm ◽

10.1016/j.hrthm.2005.02.787 ◽

2005 ◽

Vol 2 (5) ◽

pp. S251-S252

Author(s):

Tapan G. Rami ◽

Stuart J. Beldner ◽

Rupa Bala ◽

Jonathan S. Sussman ◽

William H. Sauer ◽

...

Keyword(s):

Ventricular Tachycardia ◽

Purkinje Fiber ◽

Qrs Morphology ◽

Exit Block

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Abstract 13286: Non-Specific Intraventricular Conduction Delay and Risk of Sudden Death

Circulation ◽

10.1161/circ.130.suppl_2.13286 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Audrey Uy-Evanado ◽

Carmen Teodorescu ◽

Kyndaron Reinier ◽

Kumar Narayanan ◽

Harpriya Chugh ◽

...

Keyword(s):

Sudden Cardiac Death ◽

General Population ◽

Left Bundle Branch Block ◽

Cardiac Death ◽

Conduction Delay ◽

Bundle Branch Block ◽

Intraventricular Conduction ◽

Qrs Morphology ◽

Qrs Duration ◽

Intraventricular Conduction Delay

Introduction: We and others have reported an independent association between prolonged QRS duration and risk of sudden cardiac death (SCD) in the general population. Left and right bundle branch block have been studied previously, but there is little information regarding non-specific intraventricular conduction delay and risk of SCD. Hypothesis: Completed conduction defects, including non-specific IVCD, are associated with increased SCD risk. Methods: Sudden cardiac death cases and controls from an ongoing large population based study in the Northwestern US (2002 to 2010) were included if age ≥ 35 years with a non-paced 12-lead ECG (recorded prior and unrelated to SCD in cases). QRS morphology was subcategorized as normal, intermediate [left anterior fascicular block (LAFB), left posterior fascicular block (LPFB), and incomplete right or left bundle branch block (IRBBB/ILBBB)] or completed conduction defects [left bundle branch block (LBBB), right bundle branch block (RBBB), or nonspecific intraventricular conduction delay (IVCD)]. Comparisons were conducted using chi-square tests for categorical variables and independent samples t-tests for continuous variables. Logistic regression was used to evaluate the association of QRS morphology with SCD. Results: We evaluated 761 SCD cases (64% male) and 539 controls (65% male). Cases were significantly older (69.7 vs 66.3 years, p<0.0001) with greater QRS duration (102 vs. 98 ms, p=0.001). For conduction categories, intermediate or completed conduction defects were significantly more common in cases whereas normal QRS morphology was more common among controls (p=0.01). And for specific morphology overall, QRS morphology patterns differed between cases and controls (p=0.03); abnormal QRS morphologies were more frequent in cases than controls except for LAFB. After adjustment for age and gender, however, only a finding of LBBB or non-specific IVCD remained a significant predictor of SCD [OR 1.34 (95% CI 1.03-1.75)]. Conclusions: LBBB and non-specific IVCD, but not RBBB, are significant predictors of SCD in the general population. These findings contribute to the utility of the 12-lead EKG for SCD risk stratification.

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