Chapter 24 ECG Differential Diagnoses Instant Reviews
This chapter presents a series of boxes that summarize selected aspects of ECG differential diagnosis for easy reference. For the most part the boxes recap topics covered in this book. However, some advanced topics are briefly mentioned, with additional discussion available in references cited in the Bibliography.
Low-Voltage QRS Complexes
Wide QRS Complex (Normal Rate)
Left Axis Deviation (QRS Axis of −30° or More Negative)
Right Axis Deviation (QRS Axis of +90° or More Positive)
QT(U) Prolongation (Long QT Syndromes)
∗ For an excellent, updated review of drugs associated with the acquired long QT syndrome and torsades de pointes risk, see the Arizona Cert website: www.azcert.org/medical-pros/drug-lists/browse-drug-list.cfm.
∗∗ The Romano-Ward syndrome is the classic, general term used to designate a number of specific, inherited abnormalities in ion channel function (“channelopathies”) that are associated with prolongation of ventricular repolarization (long QT-U) and increased risk of torsades de pointes (see Chapter 16). These hereditary ion channel (potassium, sodium, or calcium) disorders can prolong and increase heterogeneity of ventricular repolarization.