Who can have heart failure

Anyone can have heart failure, even young children (especially children born with a heart defect). However, it’s much more common in older people, because:

Older people are more likely to have other heart problems that can cause heart failure

Older people are more likely to have high blood pressure and diabetes, which can lead to heart failure

The heart's walls stiffen with age

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Effect of pH and Temperature

Effect of pH and Temperature on Oxygen Transport In addition to changes in P O 2 , the loading and unloading reac- tions are influenced by changes in the affinity (bond strength) of hemoglobin for oxygen. Such changes ensure that active skeletal muscles will receive more oxygen from the blood than they do at rest. This occurs as a result of the lowered pH and increased temperature in exercising muscles. The affinity is decreased when the pH is lowered and increased when the pH is raised; this is called the Bohr effect. When the affinity of hemoglobin for oxygen is reduced, there is slightly less loading of the blood with oxygen in the lungs but greater unloading of oxygen in the tissues. The net effect is that the tissues receive more oxygen when the blood pH is lowered (table 16.8). Since the pH can be decreased by carbon dioxide (through the formation of carbonic acid), the Bohr effect helps to provide more oxygen to the tissue...

Pathophysiology of heart failure

Pathophysiology of heart failure In heart failure, the heart may not provide tissues with adequate blood for metabolic needs, and cardiac-related elevation of pulmonary or systemic venous pressures may result in organ congestion. This condition can result from abnormalities of systolic or diastolic function or, commonly, both. Although a primary abnormality can be a change in cardiomyocyte function, there are also changes in collagen turnover of the extracellular matrix. Cardiac structural defects (eg, congenital defects, valvular disorders), rhythm abnormalities (including persistently high heart rate), and high metabolic demands (eg, due to thyrotoxicosis) also can cause HF.

Frank-Starling Law of the Heart

Frank-Starling Law of the Heart Two physiologists, Otto Frank and Ernest Starling, demonstrated that the strength of ventricular contraction varies directly with the end-diastolic volume (fig. 14.2). Even in experiments where the heart is removed from the body (and is thus not subject to neural or hormonal regulation) and where the still-beating heart is filled with blood flowing from a reservoir, an increase in EDV within the physiological range results in increased contraction strength and, therefore, in increased stroke volume. This rela- tionship between EDV, contraction strength, and stroke volume is thus a built-in, or intrinsic, property of heart muscle, and is known as the Frank-Starling law of the heart.

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