Selected Clinical Disorders

This chapter on selected clinical disorders is meant to unite various clinical vignettes that did not quite fit into other chapters. The text combines electrolyte derangements, hypertrophic obstructive cardiomyopathy (HoCM), pericarditis, and other noncardiac pathologies that can affect the ECG. Electrolyte derangements are frequent contributors to ECG abnormalities, both for elevated values and reduced concentrations of the relevant electrolyte. HoCM can be a challenging entity to diagnose clinically, and its ECG findings may mimic signs of left ventricular hypertrophy (LVH), depending upon the type. As discussed in the previous chapter, pericarditis may be confused for an ST-segment elevation myocardial infarction (STEMI). Finally, noncardiac conditions like chronic obstructive pulmonary disease (COPD) and multiple intracranial pathologies (such as an intracranial hemorrhage, ischemic stroke, and cerebral edema) can cause changes to the surface ECG. As is the case with every ECG, the tracing must be interpreted in the clinic context; stated differently, no ECG should be interpreted in a vacuum, as clinical nuances may dramatically change the assessment and plan for the patient.