Figure 2.

Diversity of phenotypes accompanying heritable dilated cardiomyopathy. A, Electrocardiographic tracings, revealing conduction-system abnormalities in patients with dilated cardiomyopathy. Top, First-degree atrioventricular (AV) block with prolonged interval (horizonal bar = .4 s) between atrial P wave (↓) and subsequent ventricular QRS wave. Middle, Second-degree AV block; note that a QRS complex does not follow the third or sixth P wave. Bottom, Presence of atrial fibrillation, with absence of P waves and irregular rhythm of ventricular QRS complexes. B, Plantar (and palmar) keratosis, which accompanies dilated cardiomyopathy in Naxos syndrome. C, Audiogram showing normal hearing (triangles) in comparison to sensorineural hearing loss in patients with dilated cardiomyopathy due to a mutation at chromosome 6q23-24. White circles (○) and crosses (×) denote sound transmitted through air into the right and left ear, respectively. Note that hearing loss is symmetric and affects air and bony (black circles [●]) transmission of sound.