Which diagnostic test would best show ventricular ectopy in a patient suspected of having dilated cardiomyopathy (DCM)?

In evaluating a patient suspected of having dilated cardiomyopathy (DCM), an electrocardiogram (ECG or EKG) is the most effective diagnostic test for visualizing ventricular ectopy. DCM is characterized by ventricular dilation and impaired systolic function, which can lead to various types of arrhythmias, including ventricular ectopic beats.

The ECG provides a real-time assessment of the heart's electrical activity and is designed to detect abnormalities in heart rhythm. Ventricular ectopy often presents as premature ventricular contractions (PVCs), which can be easily identified on an ECG by observing the characteristic changes in the waveform during the ventricular depolarization phase.

In contrast, while a chest X-ray can give insights into the heart's size and potential congestion, it does not provide information regarding the electrical activity or specific arrhythmias. An echocardiogram is invaluable for assessing the structural and functional aspects of the heart, including wall motion abnormalities and ejection fraction, but it does not directly show ectopic beats. Finally, a cardiac MRI offers detailed imaging of the heart's anatomy and can assess myocardial scarring or fibrosis, yet it is not primarily used for detecting acute electrical abnormalities such as ectopy.

Therefore, the electro