Page 250 - ACCCN's Critical Care Nursing

Cardiovascular Alterations and Management 227

The phases that follow, from II to IV, are managed in the and/or corticosteroids. Approximately 1–5% of AMI
outpatient setting and begin with assessment, liaison patients develop pericarditis as a late complication, 2
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with multidisciplinary professionals and health educa- weeks to a few months post-AMI. Usually this late-onset
tion. Phase II occurs in the immediate postdischarge pericarditis is associated with Dressler’s syndrome and
period and includes liaison with community-based carers may be an autoimmune response to myocardial injury.
and services and further assessment. In phase III, tailored, This is a chronic condition requiring systemic corticoste-
supervised exercise programs are usually conducted and roid treatment.
there is a range of psychosocial interventions, such as
support sessions and stress management. Finally, in phase Structural defects
IV the focus is on chronic disease management and main- Myocardial tissue death may be catastrophic if it is exten-
taining risk modification behaviours. All phases require sive or results in rupture of ventricular or papillary muscle.
incorporation of the principles of adult learning to maxi- These conditions are rare and symptoms develop rapidly.
mise learning and behaviour change. These principles Intraventricular septal rupture is usually associated with
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include recognition of ‘readiness to learn’. Adults are anterior MI. The patient develops progressive dyspnoea,
ready to learn most effectively when they are physically tachycardia and pulmonary congestion, as well as a loud
and emotionally stable and are aware of the problem or systolic murmur associated with a thrill felt in the para-
need to learn. Nurses, because of their expertise and con- sternal area. If a pulmonary artery catheter is present,
tinual presence, are best placed to assess and provide blood samples from the right atrium and right ventricle
education at optimal times. will reveal a higher than usual oxygen content. Diagnosis
Complications of Myocardial Infarction must be confirmed by cardiac catheterisation, and urgent
Cardiogenic shock surgery is required.
Papillary muscle rupture most often occurs 2–7 days after
Cardiogenic shock occurs as a complication of MI in
about 5–10% of patients and is the most common cause MI. Patients experience a sudden onset of pulmonary
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of death in hospitals. It arises from loss of contractile oedema secondary to pulmonary hypertension and car-
force, and generally occurs when ventricular damage is diogenic shock. Additional heart sounds and a systolic
more than 40% and ejection fraction less than 35%. Car- murmur will be heard. Urgent surgery is required, as the
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diogenic shock and the related management are described mortality rate for papillary muscle rupture is 95%.
in more detail in Chapter 12. Cardiac rupture most often occurs within 5 days of MI
and is commonest in older women. The patient experi-
Arrhythmias ences continuous chest pain, dyspnoea and hypotension
Arrhythmias often occur in ACS and AMI and are often as tamponade develops. Symptoms may worsen rapidly
the cause of death in the prehospital phase. Management and result in pulseless electrical activity (PEA) unless
of the prehospital phase centres on community educa- surgery is undertaken immediately.
tion and an effective, rapidly responsive ambulance
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service, as exemplified in Seattle in the USA. Arrhyth- HEART FAILURE
mias may be generated by poorly perfused tissue and In normal circumstances, the heart is a very effective,
electrolyte alterations, and increased sympathetic tone efficient pump with reserve mechanisms available to
during infarction, but are more often due to a failing left allow output to meet changing demands. These mecha-
ventricle. They may also complicate reperfusion after suc- nisms include (a) increasing heart rate to increase total
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cessful revascularisation. It is essential to rapidly and cardiac output, (b) dilation to create muscle stretch and
effectively treat arrhythmias in the ACS and AMI context. more effective contraction, (c) hypertrophy of myocytes
The goal of treatment is to maintain cardiac output while over time to generate more force, and (d) increasing
reducing workload. Arrhythmias and management are stroke volume by increasing venous return and increased
described in Chapter 11.
contractility. Heart failure is a complex clinical condition
Pericarditis that is characterised by an underlying structural abnor-
Pericarditis is an inflammation of the visceral and parietal mality or dysfunction that results in the inability of the
ventricle to fill with or eject blood. The condition is also
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layers of the pericardium that cover the heart. This inflam- known as congestive cardiac failure, a term commonly
mation occurs in approximately 20% of AMI patients used in the USA but not in Australia. Chronic heart failure
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within the following 2–3 days. The patient experiences (CHF) describes the long-term inability of the heart to
chest pain, which may be confused with ischaemic pain. meet metabolic demands.
This confusion with an ischaemic event may be com-
pounded by the additional presence of ST segment eleva- The burden of disease associated with heart failure is on
tion on the ECG. However, pericardial pain increases with the rise due to our ageing population, the prevalence of
deep inspiration and a pericardial rub is often present. coronary heart disease and hypertension, the decrease in
Electrocardiographically, the elevated ST segments of fatality from acute coronary syndrome and improved
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pericarditis are typically concave upwards (saddle-shaped) methods of diagnosis. Survival rates and prognosis for
and often widespread, contrasting with convex ST segment heart failure patients are extremely poor. Approximately
elevation limited to the distribution of a single coronary 50% of patients diagnosed with heart failure will die
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artery in infarction. Pericarditis normally responds to within five years of diagnosis. 56-58 When compared with
anti-inflammatory treatment by aspirin, indomethacin those patients with cancer, heart failure patients have the