1/13/2010 @ 5:45:58 am by electricaelectronics.com
Heart Failure p9
When assessing heart failure in a patient it is important to know
what the contributing factors are. According to Dr Phillip DuPont, M.D., Ph.D.
Professor of Cardiopulmonary Pathophysiology and Prevention at Benedictine
University (personal communication, January 23, 2009) if the primary cause is
long-term hypertension then arteriosclerosis causing hardening of the blood
vessels in the arteries and the kidneys should be investigated. The patient
described in the case has had a history of elevated blood pressure for an
undefined period of time and he is experiencing edema, dyspnea, cyanosis, and a
cough with pink frothy sputum. These symptoms all point to acute congestive
heart failure with pulmonary edema. Heart failure can originate from the right
or left side of the heart and the causes are different. Right-sided heart
failure is usually caused as a result of left sided heart failure. If
right-sided failure occurs independently of left sided failure it is most
likely secondary to lung disease (McCance, K.L. & Huether, S.E. 2006). Left
sided heart failure is either systolic or diastolic and is known as congestive
heart failure. If it is acute and severe it results in pulmonary edema.
There are many compensatory mechanisms used by the
body during heart failure: The Frank-Starling mechanism, neurohormonal
alterations, and ventricular hypertrophy and remodeling (Lilly 2007).The Frank-Starling theory essentially states
that there is a change in preload that allows for a larger stroke volume and
increased heart contraction. It happens in response to an increase in
ventricular end-diastolic volume. The fibers of the heart are stretched to help
this process. In heart failure this compensatory mechanism may not work because
the fibers can only be stretched to a certain point. Rising pressure in the
left atrium eventually leads to pulmonary edema. In early stages of heart
failure neurohormonal alterations such as the adrenergic nervous system attempt
to make up for decreased cardiac output.
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