Quantitative PCR as an Alternative in the Diagnosis of Long-QT Syndrome

Table 1

The frequency occurrence of LQTS1-3, ECG characteristics for each type of the disease, and the most common stimuli leading to fatal cardiac events.

Type of the disease	Ion current	Functional consequence	Frequency of occurrence among all types of LQTS	ECG characteristics	Stimuli leading to fatal cardiac events	Penetrance
LQTS1	K	↓	40%–50%		Gymnastics 68%; Stress 14%; Sleep, auditory stimulus 9%,; Others 9%	62%
LQTS2	K	↓	35%–40%		Gymnastics 29%; Stress 48%; Sleep, auditory stimulus 22%,; Others 1%	75%
LQTS3	Na	↑	2%–8%		Gymnastics 4%; Stress 12%; Sleep, auditory stimulus 64%,; Others 20%	90%