What are the guidelines for EKG (electrocardiogram) evaluation and management?

Guidelines for ECG Evaluation and Management

The electrocardiogram (ECG) is the only practical, noninvasive method for recording and analyzing abnormalities of cardiac rhythm and is the first choice for patients presenting with chest pain, dizziness, or syncope, which may be predictive of sudden death or myocardial infarction. 1

Definition and Purpose of ECG

• A standard 12-lead ECG is a record of electrical activity of the heart that must be interpreted by a qualified physician and made part of the patient's medical record 1
• The ECG serves as an independent marker of myocardial disease, reflects electrophysiologic and hemodynamic alterations, and provides essential information for diagnosis and therapy of cardiac disorders 1
• Computer-interpreted ECGs without physician review are not recognized as properly interpreted ECGs 1

Primary Indications for ECG (Class I)

• Patients presenting with chest pain, dizziness, or syncope 1, 2
• Patients with suspected acute coronary syndrome (ACS) where timely interpretation guides reperfusion therapy 2, 3
• Continuous ECG monitoring for hospitalized patients admitted for syncope evaluation with suspected cardiac etiology 1
• Patients receiving therapy known to produce ECG changes that correlate with therapeutic responses or progression of disease 1
• Patients receiving medications that may produce adverse effects detectable by ECG changes 1

Specific Clinical Scenarios Requiring ECG

• Symptoms warranting ECG evaluation:

  • Syncope and near-syncope 1
  • Unexplained change in the usual pattern of angina pectoris 1
  • New or worsening dyspnea 1, 2
  • Extreme and unexplained fatigue, weakness, or prostration 1
  • Palpitations 1, 2

• Preoperative evaluation:

  • All patients with known cardiovascular disease undergoing cardiac or non-cardiac surgery 1
  • Patients after cardiac surgery or extensive pulmonary surgery until condition stabilizes 1

• Device monitoring:

  • Patients with implanted pacemakers or antitachycardia devices 1
  • ECG indicated soon after pacemaker insertion/revision and whenever malfunction is suspected 1

Advanced ECG Monitoring Options

• External loop recorder:

  • Records and stores data from preprogrammed arrhythmias or patient activation 1
  • Useful for patients with infrequent symptoms 1

• Mobile cardiac outpatient telemetry:

  • Records and transmits data for up to 30 days 1
  • Automatically transmits significant arrhythmias through wireless network 1
  • Indicated for spontaneous symptoms related to syncope and rhythm correlation 1
  • Appropriate for high-risk patients whose rhythm requires real-time monitoring 1

• Implantable cardiac monitor:

  • Subcutaneously implanted device with 2-3 year battery life 1
  • Indicated for recurrent, infrequent, unexplained syncope of suspected arrhythmic cause 1

Special Testing Scenarios

• Electrophysiological Study (EPS):

  • Useful for evaluation of selected patients with syncope of suspected arrhythmic etiology 1
  • Not recommended for syncope evaluation in patients with normal ECG, cardiac structure and function unless arrhythmic etiology is suspected 1

• Tilt-Table Testing:

  • Useful when diagnosis is unclear after initial evaluation for patients with suspected vasovagal syncope 1
  • Useful for patients with syncope and suspected delayed orthostatic hypotension 1
  • Reasonable to distinguish convulsive syncope from epilepsy 1
  • Not recommended to predict response to medical treatments for vasovagal syncope 1

ECG Interpretation Considerations

• ECG interpretation requires understanding of its sensitivity and specificity 1
• Diagnoses of structural changes (myocardial infarction, hypertrophy) or pathophysiologic changes are made by inference 1
• Comparison to previous ECGs is essential when available 3
• Serial ECGs are indicated when symptoms persist or change, or when initial ECG is non-diagnostic 2, 3

Special Populations

• Dialysis patients: ECG evaluation recommended at dialysis initiation and annually thereafter 2
• Transplant waitlist patients: Periodic ECG evaluation based on risk factors and prior cardiac history 2

Limitations and Pitfalls

• ECG alone may not be sufficient for definitive diagnosis in complex cases 2
• Incorrect ECG diagnosis can have significant undesirable medical and legal consequences 1
• ECG interpretation should always be performed in the clinical context of the patient 2
• For patients with acute symptoms suggesting life-threatening conditions, in-person evaluation in an emergency setting is preferable to remote ECG image evaluation 2