Reconstitution of native intrinsic conduction in patients with chronic conduction block with His bundle pacing

Introduction: While acute (Ac) right bundle branch block (RBBB) may be in proximal HB (lead fixation injury) and chronic (Ch) RBBB in distal HB, they both cause terminal QRS delay. Both types of RBBB may be corrected with non-selective (NS) His bundle pacing (HBP), however the mechanism is unknown. Hypothesis: To study the role of high (5V) and low (1V) pacing voltage as well as presence of pre-excitation (in NS-HBP) in resolving Ac and chronic Ch-RBBB. Methods: Of the thirty-nine patients (27 ChRBBB and 12 AcRBBB), 25 ChRBBB and 10 AcRBBB patients showed NS-HBP at 5V and 11/25 ChRBBB and 6/12 AcRBBB patients transitioned to selective (S)-HBP at 1V. Four patients showed S-HBP at 5V and 1V. Results: 1)During NS-HBP at 5V: (In 25 ChRBBB and 10 Ac-RBBB) Complete resolution occurred 12/25ChRBBB and in all 10 AcRBBB. A partial resolution of ChRBBB occurred 13/25 ChRBBB.2. During NS-HBP at 1V: (6/14 ChRBBB and 2/4 AcRBBB showed complete resolution at 1V, remainder showed incomplete RBBB3. During S-HBP at 5V : (2 ChRBBB 2 AcRBBB) only 1 AcRBBB showed resolution of RBBB. 4. During S-HBP at 1V : All 13 ChRBBB and 8 AcRBBB did not show resolution os RBBB including 11 Ch-RBBB and 6 Ac-RBBB RBBB which resolved during 5V NS-HBP, abruptly recurred on transition to S-HBP at a mean of 2.4±0.8V. Conclusions: 1)The lack of RBBB resolution with S-HBP suggests that pacing site was proximal to site of block, however, from the same site NS-HBP either completely or incompletely resolved both Ac- and Ch-RBBB. 2) Partial resolution of RBBB in NS-HBP may be explained by right ventricular free wall pre-excitation when site of Ch-RBBB is distal.3) Complete resolution of both acute and Ch-RBBB in NS-HBP, more so at high pacing voltage, suggest that peri-Hisian tissues may behave more like a specialized conduction tract which uniquely resolves conduction block.

Download Full-text

His bundle pacing in older patient with continuous proximal atrio-ventricular block after myocardial infarction

In a good rythm ◽

10.5604/01.3001.0012.7128 ◽

2018 ◽

Vol 3 (48) ◽

pp. 24-27

Author(s):

Agnieszka Wojdyła-Hordyńska ◽

Grzegorz Hordyński ◽

Pavel Dąbrowski ◽

Tomasz Pawlik ◽

Agata Kubal-Tkocz ◽

...

Keyword(s):

Myocardial Infarction ◽

Diastolic Dysfunction ◽

Conduction Block ◽

Coronary Intervention ◽

Atrioventricular Conduction ◽

His Bundle ◽

His Bundle Pacing ◽

Conduction Disorders ◽

Percutaneous Coronary ◽

Pr Interval

His bundle pacing (HBP) synchronizes atrio-ventricular and intraventricular delays. We observed the relationship between the level of atrio-ventricular block, ventricles synchrony, diastolic function improvement in a patient with moderate systolic disorders and diastolic dysfunction after myocardial infarction. HBP may be useful to treat conduction disorders and prevent further systolic and diastolic dysfunction. We present the case of a 92-year-old man in a very good general psychophysical status, treated with percutaneous coronary intervention of circumferential branch of left coronary artery angioplasty due to myocardial infarction, regional contractility disorders of left ventricle with ejection fraction (LVEF) 45%, and observed long PR interval with paroxysmal second degree atrioventricular conduction block. A successful implantation of a permanent HBP lead in the postinfarction period was performed. The His bundle capture restored AV synchrony and diminished diastolic disorders. Our case demonstrates that atrioventricular conduction disorders in the course of myocardial infarction may be corrected by HBP.

Download Full-text