John Aalen1, Petter Storsten1, Espen W Remme2, Per A Sirnes3, Ola Gjesdal4, Camilla K Larsen1, Erik Kongsgaard5, Espen Boe2, Helge Skulstad6, Jonny Hisdal7, Otto A Smiseth8. 1. Institute for Surgical Research, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Center for Cardiological Innovation, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway. 2. Institute for Surgical Research, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Center for Cardiological Innovation, Oslo University Hospital, Rikshospitalet, Oslo, Norway. 3. Ostlandske Hjertesenter, Moss, Norway. 4. Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway. 5. Center for Cardiological Innovation, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway. 6. Institute for Surgical Research, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Center for Cardiological Innovation, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway. 7. Institute of Clinical Medicine, University of Oslo, Oslo, Norway. 8. Institute for Surgical Research, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Center for Cardiological Innovation, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway. Electronic address: otto.smiseth@ous-hf.no.
Abstract
OBJECTIVES: This study sought to investigate the hypothesis that patients with left bundle branch block (LBBB) are hypersensitive to elevated afterload. BACKGROUND: Epidemiological data suggest that LBBB can provoke heart failure in patients with hypertension. METHODS: In 11 asymptomatic patients with isolated LBBB and 11 age-matched control subjects, left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) were measured by echocardiography. Systolic arterial pressure was increased by combining pneumatic extremity constrictors and handgrip exercise. To obtain more insight into mechanisms of afterload response, 8 anesthetized dogs with left ventricular (LV) micromanometer and dimension crystals were studied during acutely induced LBBB and aortic constriction. Regional myocardial work was assessed by LV pressure-dimension analysis. RESULTS: Consistent with normal afterload dependency, elevation of systolic arterial pressure by 38 ± 12 mm Hg moderately reduced LVEF from 60 ± 4% to 54 ± 6% (p < 0.01) in control subjects. In LBBB patients, however, a similar blood pressure increase caused substantially larger reduction in LVEF (p < 0.01), from 56 ± 6% to 42 ± 7% (p < 0.01). There were similar findings for GLS. In the dog model, aortic constriction abolished septal shortening (p < 0.02), and septal work decreased to negative values (p < 0.01). Therefore, during elevated systolic pressure, the septum made no contribution to global LV work, as indicated by net negative work, and instead absorbed energy from work done by the LV lateral wall. CONCLUSIONS: Moderate elevation of arterial pressure caused marked reductions in LVEF and GLS in patients with LBBB. This reflects a cardiodepressive effect of elevated afterload in the dyssynchronous ventricle and was attributed to loss of septal function.
OBJECTIVES: This study sought to investigate the hypothesis that patients with left bundle branch block (LBBB) are hypersensitive to elevated afterload. BACKGROUND: Epidemiological data suggest that LBBB can provoke heart failure in patients with hypertension. METHODS: In 11 asymptomatic patients with isolated LBBB and 11 age-matched control subjects, left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) were measured by echocardiography. Systolic arterial pressure was increased by combining pneumatic extremity constrictors and handgrip exercise. To obtain more insight into mechanisms of afterload response, 8 anesthetized dogs with left ventricular (LV) micromanometer and dimension crystals were studied during acutely induced LBBB and aortic constriction. Regional myocardial work was assessed by LV pressure-dimension analysis. RESULTS: Consistent with normal afterload dependency, elevation of systolic arterial pressure by 38 ± 12 mm Hg moderately reduced LVEF from 60 ± 4% to 54 ± 6% (p < 0.01) in control subjects. In LBBB patients, however, a similar blood pressure increase caused substantially larger reduction in LVEF (p < 0.01), from 56 ± 6% to 42 ± 7% (p < 0.01). There were similar findings for GLS. In the dog model, aortic constriction abolished septal shortening (p < 0.02), and septal work decreased to negative values (p < 0.01). Therefore, during elevated systolic pressure, the septum made no contribution to global LV work, as indicated by net negative work, and instead absorbed energy from work done by the LV lateral wall. CONCLUSIONS: Moderate elevation of arterial pressure caused marked reductions in LVEF and GLS in patients with LBBB. This reflects a cardiodepressive effect of elevated afterload in the dyssynchronous ventricle and was attributed to loss of septal function.
Authors: Moritz Blum; Djawid Hashemi; Laura Astrid Motzkus; Marthe Neye; Aleksandar Dordevic; Victoria Zieschang; Seyedeh Mahsa Zamani; Tomas Lapinskas; Kilian Runte; Marcus Kelm; Titus Kühne; Elvis Tahirovic; Frank Edelmann; Burkert Pieske; Hans-Dirk Düngen; Sebastian Kelle Journal: Front Cardiovasc Med Date: 2020-06-30
Authors: Bálint Károly Lakatos; Mihály Ruppert; Márton Tokodi; Attila Oláh; Szilveszter Braun; Christian Karime; Zsuzsanna Ladányi; Alex Ali Sayour; Bálint András Barta; Béla Merkely; Tamás Radovits; Attila Kovács Journal: ESC Heart Fail Date: 2021-03-23
Authors: Justus Stenzig; Marc D Lemoine; Aaltje M S Stoter; Kinga M Wrona; Marta Lemme; Wesam Mulla; Yoram Etzion; Thomas Eschenhagen; Marc N Hirt Journal: J Mol Cell Cardiol Date: 2021-10-08 Impact factor: 5.000
Authors: Rafael Duarte de Sousa; Carlos Danilo Miranda Regis; Ittalo Dos Santos Silva; Paulo Szewierenko; Renato de Aguiar Hortegal; Henry Abensur Journal: Arq Bras Cardiol Date: 2020 May-Jun Impact factor: 2.000