The increased availability of data collected among genotyped LQTS patients has allowed developing risk-stratification models based on the genetic substrate. Zareba et al. in 1998 provided the first gene-specific assessment of the natural history of the disease. Such observations were further refined by Priori et al. who also provided the first risk-stratification scheme based on the genotype. This study showed that the QT interval duration, the genotype, and the gender are significantly associated with the outcome. A QTc interval >500 msec determines a worse prognosis. However, LQT1 patients have a better prognosis vs. LQT2 and LQT3 with similar QT. Gender has no influence among LQT1 patients, whereas a higher risk was identified for LQT2 females and LQT3 males.
Recent, still preliminary evidences suggested that risk stratification may be further refined when the position of a mutation on the predicted protein topology is taken into consideration. Among others, epidemiological findings from the International LQTS Registry showed that LQT2 patients with mutation in the pore region are at greater risk of cardiac events (syncope and cardiac arrest) than patients with nonpore mutations.
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The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.