This chapter is relevant to the grim warning at the front of the 2017 CICM Primary Syllabus, which threatens the exam candidate that "for all sections of the Syllabus an understanding of ... physiology at the extremes of age... is expected". If so, then it is not expected with the same ardour as many other subjects, as it has only ever appeared once in the exam. Question 19 from the first paper of 2015 asked the candidates to "describe the effects of ageing on the cardiovascular system", generating a pass rate of 29%. For the remaining 71%, this chapter offers a short summary of the main points.
- Structural changes:
- LV hypertrophy
- Interventricular septal hypetrophy
- LVOT narrowing
- Valvular sclerosis
- Degeneration of sympethetic innervation
- Dilation of aorta and large arteries
- Thickening of arterial walls
- Decreased windkessel effect
- Functional changes:
- Increased systolic function
- Decreased diastolic function
- Increased atrial diastolic contribution (atrial "kick")
- Decreased cardiac output (by 1% per year)
- Decreased maximal heart rate
- Increased cardiac workload (due to afterload increase)
- Blunted baroreceptor reflexes
- SA node atrophy
- Conductive tissue loss
- Action potential prolongation
- Decreased arterial compliance
- Decreased endothelial NO-mediated vasodilatory function
- Systolic blood pressure increases
- Pulse pressure increases (diastolic pressure increases less than systolic)
- Pulmonary arterial pressure increases
- Increased ANP secretion
- Increased circulating catecholamine levels
- Decreased renin, angiotensin and aldosterone concentrations
Normal age-related changes are the subject here. Sure, your coronary arteries might be overgrown with greasy calcified stalactites and your mitral annulus might have dilated hideously, but those are pathological changes, old man - they have nothing to do with the beautiful natural process of ageing. The best account of this noble dignified descent into the wormy grave is offered by Karavidas et al (2010), which also happens to be free. Unless otherwise stated, everything in the summary below comes from this article. Alternatives include Safar (1990), Ribera-Casasado (1999) and Ferrari et al (2003). These aren't free, and given the relative neglect of this topic in the CICM exams, there's probably no point wasting your time reviewing them, as the authors themselves will remind you that life is short.
Safar, Michel. "Ageing and its effects on the cardiovascular system." Drugs 39.1 (1990): 1-8.
Ribera-Casado, J. M. "Ageing and the cardiovascular system." Zeitschrift für Gerontologie und Geriatrie 32.6 (1999): 412-419.
Ferrari, Alberto U., Alberto Radaelli, and Marco Centola. "Invited review: aging and the cardiovascular system." Journal of Applied Physiology 95.6 (2003): 2591-2597.
Karavidas, Apostolos, et al. "Aging and the cardiovascular system." Hellenic J Cardiol 51.5 (2010): 421-427.
Lam, Carolyn SP, et al. "Aortic Root Remodeling Over the Adult Life Course." Circulation 122.9 (2010): 884-890.
Lam, Carolyn SP, et al. "Age-associated increases in pulmonary artery systolic pressure in the general population." Circulation 119.20 (2009): 2663.
Ruan, Qinyun, and Sherif F. Nagueh. "Effect of age on left ventricular systolic function in humans: a study of systolic isovolumic acceleration rate." Experimental physiology 90.4 (2005): 527-534.
Brandfonbrener, Martin, MILTON LANDOWNE, and NATHAN W. SHOCK. "Changes in cardiac output with age." Circulation 12.4 (1955): 557-566.
Christou, Demetra D., and Douglas R. Seals. "Decreased maximal heart rate with aging is related to reduced β-adrenergic responsiveness but is largely explained by a reduction in intrinsic heart rate." Journal of applied physiology 105.1 (2008): 24-29.
McLean, Miriam R., Paula Bursztyn Goldberg, and Jay Roberts. "An ultrastructural study of the effects of age on sympathetic innervation and atrial tissue in the rat." Journal of molecular and cellular cardiology 15.2 (1983): 75-92.
TZUNODA, KAZUO, et al. "Effect of age on the renin-angiotensin-aldosterone system in normal subjects: simultaneous measurement of active and inactive renin, renin substrate, and aldosterone in plasma." The Journal of Clinical Endocrinology & Metabolism 62.2 (1986): 384-389.
Arora, Rohit R., et al. "Atrial kinetics and left ventricular diastolic filling in the healthy elderly." Journal of the American College of Cardiology 9.6 (1987): 1255-1260.