Cardiomyopathies

This section will provide an overview of the ECG presentations of several common cardiomyopathies, such as:

• Takotsubo cardiomyopathy: associated with acute physiologic stress and catecholamine-induced reduction in cardiac function, leading to non-specific changes that can closely mimic ischemia. For example, it can present with T wave inversions or ST depressions and even ST elevations (with reciprocal changes) that is almost impossible to distinguish from true acute coronary syndrome without doing an invasive coronary angiogram.

• Hypertrophic cardiomyopathy: associated with non-physiologic hypertrophy of the ventricles causing characteristic ECG signs of chamber enlargement. We will also discuss a variant, apical hypertrophic cardiomyopathy, which presents with a unique ECG finding, known as "Yamaguchi T waves". We will also discuss the risk of sudden cardiac death in these cardiomyopathies.

• Infiltrative cardiomyopathy: a set of cardiomyopathies encapsulating conditions such as sarcoidosis and amyloidosis, which present with echocardiographic evidence of chamber enlargement but paradoxically low voltages on the ECG due to loss of viable myocardium. In the case of some infiltrative diseases, such as sarcoidosis, these cardiomyopathies may carry an increased risk of heart block or ventricular tachycardia.

• Arrhythmogenic cardiomyopathy: characterized by fibrofatty deposition into the myocardium, causing aberrancies in conduction and an increased risk of ventricular tachyarrhythmias. We will discuss the pathophysiology behind the disease, as well as the characteristic presentation of "epsilon waves" seen in this condition. We will also describe how to improve detection of the often elusive epsilon wave.

• Non-specific severe cardiomyopathy: we will discuss ECG signs associated with end-stage cardiomyopathy of any etiology, such as significant intraventricular conduction delay, Q waves, notching and fragmentation.