A girl who is deaf and mute dies immediately after her teacher yells at her during a lecture in class. The parents report that her brother was also deaf and mute and died suddenly during a fight. Concerned about their third child, they consult a pediatrician who during a battery of tests notices an elongated QRS complex. Upon referral to a pediatric geneticist, it is determined that the child has a loss-of-function mutation on chromosome 11p15.5 in the gene LQT1, a subunit of the slow delayed rectifier potassium channel. How does this mutation give rise to the ECG finding?
A. Increased phase 1 of ventricular action potential
B. Decreased phase 2 of ventricular action potential
C. Increased phase 3 of ventricular action potential
D. Decreased phase 0 of atrial action potential
E. Increased plateau of atrial action potential
A. Increased phase 1 of ventricular action potential
B. Decreased phase 2 of ventricular action potential
C. Increased phase 3 of ventricular action potential
D. Decreased phase 0 of atrial action potential
E. Increased plateau of atrial action potential