Left Ventricular Architechture and Mechanics
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This document provides a historical overview of the study of left ventricular architecture and mechanics. It describes early dissections in the 18th century that began to reveal the helical fiber structure of the heart. In the 19th century, Gerdy further described the helical fiber loops within the heart walls. In the 20th century, the heart was initially viewed as having uniform contracting bands, but it is now understood to have complex 3D twisting and regional variations in strain. New imaging technologies have improved understanding of diastolic function and regional differences critical to diseases like heart failure.
Left Ventricular Architechture and Mechanics
- 1. Left Ventricular Architecture and Mechanics: An Historical Perspective Michael Geoffrey Katz Senior Assistant Resident Duke University, Internal Medicine November 11, 2009
- 2. Intern Year JAR & SAR Years (?)
- 3. “The heart is important because it pumps antibiotics to the bone.” - Some guy on 6100
- 10. =
- 14. Senac - 1749 Sub-endocardial Sub-epicardial“Deep”
- 15. Wolf - 1792
- 20. Steeter -1973
- 25. Part II. The Helical Heart
- 26. Gerdy - 1823
- 32. Aorta Pulmonary Artery Basal Loop Right segment Basal Loop Left Segment Apical Loop Descending Segment Apical Loop Ascending Segment
- 33. Aorta Pulmonary Artery Basal Loop Right segment Basal Loop Left Segment Apical Loop Descending Segment Apical Loop Ascending Segment
- 34. Aorta Pulmonary Artery Basal Loop Right segment Basal Loop Left Segment Apical Loop Descending Segment Apical Loop Ascending Segment Genu Abberant fibers
- 35. Aorta Pulmonary Artery Basal Loop Right segment Basal Loop Left Segment Apical Loop Descending Segment Apical Loop Ascending Segment Myocardial Fold
- 36. Aorta Pulmonary Artery Basal Loop Right segment Basal Loop Left Segment Apical Loop Descending Segment Apical Loop Ascending Segment Right Trigone Left Trigone Myocardial fold
- 37. Aorta Pulmonary Artery Basal Loop Right segment Basal Loop Left Segment Apical Loop Descending Segment Apical Loop Ascending Segment
- 38. Aorta Pulmonary Artery Right segment Left Segment Descending Segment Ascending Segment Anterior Papillary muscle Basal Loop Apical Loop Posterior Papillary muscle
- 41. Part III. Function (From Tennis Ball to Cobra)
- 46. “Being now amazed at the novelty of the thing, I search it again and again, and having diligently enough enquired into all, it was evident, that that old and vast ulcer (for want of the help of a skilfull physician) was miraculously healed, and skinned over with a membrane on the inside, and guarded with flesh all about the brimmes or margent of it. By its pulse, and the difference or rhythm thereof, or the time which it kept, (and laying one hand upon his wrest, and the other upon his heart) and also by comparing and considering his respirations, concluded it to be no part of the lungs, but the cone or substance of the heart.”
- 51. Classic physiologic sequence of left ventricular: 1. Isovolemic contraction 2. Ejection 3. Isovolemic relaxation 4. Rapid filling 5. Slow filling
- 52. Essentially correct, but not an improvement on Harvey's observation that there is constriction and dilatation.
- 54. The complexity of ventricular form and of the changes in configuration during systole preclude assigning quantitative values for volume from measurements of any single dimension. With these reservations, pressure- circumference loops have been employed to indicate changes in the stroke work performed by those myocardial fibers lying directly beneath the circumference gauges and contributing to the change in circumference.” -Rushmer 1954
- 55. Ventricular Muscle is Not Homogeneous Does not account for multiple fiber directions Does not account for ventricular twisting Three Main Short Coming of early 20th Century Model of Cardiac Function
- 56. Change in Mindset: 2D 3D
- 57. Muscular anatomy allows • Narrowing • Shortening • Lengthening • Widening • Twisting New technologies: • High-resolution echo (showing regional strain) • MR myocardial tagging • Echo with speckle tracking to quantify torsion
- 64. A. B. C.
- 65. Isovolemic Phase / Isovolemic “Relaxation”
- 66. Cardiac Cycle – “Classic” / “Old School” Conception
- 67. Volume / Pressure Based – 2D Ventricular Myocardial Band Based– 3D
- 68. Heart failure Electrophysiology Valvular Heart Disease Structural Heart Disease Clinical Implications and Future Directions
- 69. In patients with preserved EF: Heart failure Electrophysiology Valvular Heart Disease Structural Heart Disease
- 71. Heart failure Electrophysiology Valvular Heart Disease Structural Heart Disease
- 72. Heart failure Electrophysiology Valvular Heart Disease Structural Heart Disease
- 73. Heart failure Electrophysiology Valvular Heart Disease Structural Heart Disease
- 74. Circumferential Strain as a measure of UNtwisting Control HCM HCOM
- 75. Acknowledgements
- 77. Thank You! My parents My fellow Internal Medicine Residents •And especially the hard working interns. Chief Residents •Present •Rob Harrison, M.D. •Erin Hommel, M.D. •Jamie Todd, M.D. •Past •Al Sun •Christina Barkauskas Program Leadership and Key Faculty •Diana McNeill, M.D. •Harvey Jay Cohen, M.D. •Andrew Muir, M.D. •Thomas Bashore, M.D. •Joseph Greenfield, M.D. – “The quail population of Florida is dangerously high and I’ve been called in to reduce it.”
- 79. Selected References Ballester-Rode´s M et al. European Journal of Cardio-thoracic Surgery. 2006; 29S:S139 Bertini M et al. JACC. 2009;54:1317 Bowman IA. Texas Heart Institute Journal. 1987;14:5 Buckberg G et al. Circulation. 2008;118:2571 Buckberg GD et al. European Journal of Cardio-thoracic Surgery. 2006; 29S: S165 Buckberg GD. European Journal of Cardio-thoracic Surgery. 2006; 29S:S286 Carreras F et al. European Journal of Cardio-thoracic Surgery. 2006; 29S:S50 Corno AF et al. European Journal of Cardio-thoracic Surgery. 2006; 29S:S61 Fukuda N et al. Journal of Muscle Research and Cell Motility. 2005;26:319 Garber A et al. UWOMJ. 2008;77:22 Isomura T et al. European Journal of Cardio-thoracic Surgery. 2006; 29S:S245 Katz A. Dialogues Cardiovasc Med. 2004;9:45 Key JD et al. The American Journal of Cardiology. 1979;43:1026 MacCallum JB. Johns Hopkins Hosp. Rep. 1900;9:307 McKechnie MDJ et al. Resuscitation. 2002;55:133 Maclver DH et al. Heart. 2008;94:446 Manner J. European Journal of Cardio-thoracic Surgery. 2006; 29S:S69 Rushmer RF. Physiol. Rev. 1956; 36: 400 Streeter DD et al. Circ. Res. 1973;33:656 Torrent-Guasp F et al. European Journal of Cardio-thoracic Surgery. 2005;27:191 Tubbs RS et al. International Journal of Cardiology. 2008;128:17 Wang J et al. JACC. 2009;54:1326
Editor's Notes
- #8: Leonardo da Vinci (1452-1519): Leonardo is said to have dissected 30 cadavers and to have made nearly 800 anatomic drawings. He and a friend intended to publish a treatise on anatomy, but this was never accomplished. Most of his drawings were not published until early in the 20th century. He thought of the heart, as a pump and believed that the heartbeat and the pulse were synchronous. The drawings were superb, but their influence was late and restricted. Note, image on the right demonstrates Galen’s holes.
- #9: Before proceeding, it’s worth taking a moment to reflect on what was going on in the world of pop-culture and science during the 17th century.
- #32: In 1957, Torrent-Gausp discovered the helical heart by simple hand dissection. The hearts were prepared by simple boiling in water (without any additive), in order to loosen the connective tissue. The period of boiling was judged empirically, on the appearance of fibres and depended on the size of the specimen - about 10 minutes or less for a hen heart and up to 2 hours for an adult bovine heart. After boiling, the atria, aorta and pulmonary artery were removed from the heart. The fat from the atrio-ventricular sulci was removed and all visible, superficial coronary vessels excised. Dissection of the myocardial mass was undertaken with non-toothed forceps, scalpel and scissors. Blunt dissection by fingers was generally the most satisfactory way of identifying the direction of the linear (fibre) and laminar layer) pathways.
- #40: Refolding the heart into its natural biological configuration allows definition of 2 loops, termed the transverse basal and oblique apical loops. The basal loop is circumferential and wraps around both the LV and right ventricle but does not involve the septum, a finding supported by recent diffusion tensor MRI analysis. The apical loop is composed of a descending and ascending segment that conforms to the right- and left-handed helical arrangement described by anatomists over many years.