Author + information
- Received August 23, 2018
- Revision received November 5, 2018
- Accepted November 30, 2018
- Published online February 13, 2019.
- John M. Aalen, MDa,b,c,d,
- Espen W. Remme, MSc, Dr-Inga,b,e,
- Camilla K. Larsen, MDa,b,c,d,
- Oyvind S. Andersen, MDa,b,c,d,
- Magnus Krogh, MSca,e,
- Jürgen Duchenne, MScg,h,
- Einar Hopp, MD, PhDf,
- Stian Ross, MDb,c,
- Ahmed S. Beela, MDg,h,
- Erik Kongsgaard, MD, PhDb,c,
- Jacob Bergsland, MD, PhDa,e,
- Hans H. Odland, MD, PhDb,c,
- Helge Skulstad, MD, PhDa,b,c,d,
- Anders Opdahl, MD, PhDc,
- Jens-Uwe Voigt, MD, PhDg,h and
- Otto A. Smiseth, MD, PhDa,b,c,d,∗ ()
- aInstitute for Surgical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- bCenter for Cardiological Innovation, Oslo University Hospital, Oslo, Norway
- cDepartment of Cardiology, Oslo University Hospital, Oslo, Norway
- dInstitute of Clinical Medicine, University of Oslo, Oslo, Norway
- eThe Intervention Center, Oslo University Hospital, Oslo, Norway
- fDivision of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway
- gDepartment of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
- hDepartment of Cardiovascular Diseases, University Hospitals Leuven, Leuven, Belgium
- ↵∗Address for correspondence:
Dr. Otto A. Smiseth, Department of Cardiology, Oslo University Hospital, Rikshospitalet, N-0424 Oslo, Norway.
Objectives This study sought to investigate how regional left ventricular (LV) function modifies septal motion in left bundle branch block (LBBB).
Background In LBBB, the interventricular septum often has marked pre-ejection shortening, followed by immediate relengthening (rebound stretch). This motion, often referred to as septal flash, is associated with positive response to cardiac resynchronization therapy (CRT).
Methods In 10 anesthetized dogs, we induced LBBB by radiofrequency ablation and occluded the circumflex (CX) (n = 10) and left anterior descending (LAD) (n = 6) coronary arteries, respectively. Myocardial dimensions were measured by sonomicrometry and myocardial work by pressure-segment length analysis. In 40 heart failure patients with LBBB, including 20 with post-infarct scar and 20 with nonischemic cardiomyopathy, myocardial strain was measured by speckle-tracking echocardiography and myocardial work by pressure-strain analysis. Scar was assessed by cardiac magnetic resonance imaging with late gadolinium enhancement.
Results During LBBB, each animal showed typical septal flash with pre-ejection shortening and rebound stretch, followed by reduced septal systolic shortening (p < 0.01). CX occlusion caused LV lateral wall dysfunction and abolished septal flash due to loss of rebound stretch (p < 0.0001). Furthermore, CX occlusion restored septal systolic shortening to a similar level as before induction of LBBB and substantially improved septal work (p < 0.001). LAD occlusion, however, accentuated septal flash by increasing rebound stretch (p < 0.05). Consistent with the experimental findings, septal flash was absent in patients with LV lateral wall scar due to lack of rebound stretch (p < 0.001), and septal systolic shortening and septal work far exceeded values in nonischemic cardiomyopathy (p < 0.0001). Septal flash was present in most patients with anteroseptal scar.
Conclusions LV lateral wall dysfunction and scar abolished septal flash and markedly improved septal function in LBBB. Therefore, function and scar in the LV lateral wall should be taken into account when septal motion is used to evaluate dyssynchrony.
- cardiac resynchronization therapy
- heart failure
- left bundle branch block
- myocardial work
- septal flash
Dr. Aalen was supported by a grant from the Norwegian Health Association. Drs. Larsen and Andersen received fellowships from the South-Eastern Norway Regional Health Authority. Prof. Voigt holds a personal research mandate from the Flemish Research Council. Prof. Voigt and Mr. Duchenne have received grants from the University of Leuven. Dr. Beela has received a research grant from the Egyptian Ministry of Higher Education. Dr. Odland has financial relationships with Abbot and Medtronic. Prof. Smiseth is co-inventor but no longer has ownership of the patent “Method for myocardial segment work analysis” that was used to calculate myocardial work in the clinical study. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received August 23, 2018.
- Revision received November 5, 2018.
- Accepted November 30, 2018.
- 2019 American College of Cardiology Foundation
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