VOL: 101, ISSUE: 33, PAGE NO: 28
Brendan Docherty, MSc, PGCE, RN, is nurse manager, patient access and nursing services, Prince of Wales Hospital, Sydney, AustraliaThis article is the last in a four-part series looking at the common cardiac conditions where nursing input and expertise are essential to optimise patient-focused care.
This article is the last in a four-part series looking at the common cardiac conditions where nursing input and expertise are essential to optimise patient-focused care.
When a patient has a cardiac abnormality, arrhythmia, chest pain or suffers a myocardial infarction (MI), has electrolyte imbalance or is receiving medication that may interrupt normal heart action, an electrocardiogram (ECG) is often required, either in the form of continuous three-lead monitoring or a 12-lead tracing (Docherty, 2002a; Docherty, 2003).
The 12-lead ECG is used to assist teams of health care professionals in making decisions about patient care and management, in line with physical assessment and other clinical signs and symptoms (Docherty, 2003).
Placement of the leads (Fig 1) is critical for an accurate recording and to ensure that recordings can be compared to show deterioration or improvement (Docherty, 2002b). Different positions of the limb leads will alter the appearance of the ECG and local policy should be followed.
The most commonly used part of the 12-lead ECG is the ST segment (Schroder, 2004). When elevated with the correct clinical signs and symptoms and when convex (n-shaped) it may be suggestive of MI (Docherty, 2002b; Docherty, 2003; RCUK, 2004).
It can also indicate pericarditis, especially if it follows cardiac surgery or MI and is concave in shape (U-shaped) (Marinella, 1998). ST depression is often a sign of ischaemia of the coronary arteries and is often associated with anginal pain or low haemoglobin levels leading to ischaemia (Docherty, 2003; RCUK, 2004).
Acute myocardial infarction (AMI) is the sudden occlusion of a coronary artery leading to myocardial cell death and heart failure or incompetence (RCUK, 2004).
Ischaemic heart disease was the world's leading cause of death, and AMI is one of the most common causes - although mortality has dropped in many developed countries over the past decade (Antman and Van de Werf, 2004).
The risk of AMI increases with age and is more common in lower socioeconomic groups (Schroder, 2004). AMI can lead to cardiogenic shock (for which the mortality rate is extremely high, especially when associated with biventricular failure); arrhythmias; valve incompetence and death (Smith, 2000).
Management aims for AMI include pain relief, restoration of blood supply, reduction and correction of complications, decreased mortality and improved quality of life (Docherty, 2003; Schroder, 2004). Common effective treatments include (Docherty, 2003; Antman and Van de Werf, 2004; RCUK, 2004):
- Thrombolysis - within six hours, and possibly within 12 hours. For example, streptokinase, tissue plasminogen activator and tenecteplase;
- Beta (b) blockers - reduce rates of reinfarction and chest pain. For example, bisoprolol, atenolol and carvedilol (mostly used in heart failure);
- Angiotensin converting enzyme (ACE) - originally used to treat hypertension, but in AMI decrease mortality and sudden cardiac death;
- Primary percutaneous transluminal coronary angioplasty (PTCA) - reduces death rates, non-fatal reinfarction, and stroke compared with thrombolysis. This can only be undertaken in hospitals with the correct facilities and personnel.
Response to cardiac abnormalities is initially the nurse's role (Table 1). However, signs and symptoms may be masked initially and at-risk scoring may help with assessment. At-risk patients need frequent monitoring, which should be increased if their condition deteriorates. For example, hourly haemodynamic and neurological observations should move to half or quarter-hourly, reported and acted on as necessary (Docherty, 2002b; Smith, 2000; RCUK, 2004).
- This article has been double-blind peer-reviewed.
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