Influence of the Genotype on the Clinical Course of the Long-QT Syndrome
Key result
Mutations at the LQT1 (63%) or LQT2 (46%) locus were associated with a higher frequency of cardiac events than LQT3 mutations (18%, P<0.001), though LQT3 events were more often lethal (20% vs 4%).
Why the study?
Does the specific genotype (LQT1, LQT2, or LQT3) influence the clinical course and risk of cardiac events in patients with congenital long-QT syndrome?
Population
1,378 members of 38 families enrolled in the International Long-QT Syndrome Registry, including 541…
Comparison
LQT1 or LQT2 genotype vs LQT3 genotype
Design
Cohort
Follow-up
from birth through the age of 40 years
Authors
Discussion
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Member takes
Implication
May support genotype-informed monitoring in long-QT syndrome families; leaves open therapeutic implications.
Study Design
Type
Cohort (n=1,378)
Multicenter
Yes
Structured PICO
Does the specific genotype (LQT1, LQT2, or LQT3) influence the clinical course and risk of cardiac events in patients with congenital long-QT syndrome?
P
Population
1,378 members of 38 families enrolled in the International Long-QT Syndrome Registry, including 541 genotyped members of which 246 were gene carriers (112 with LQT1, 72 with LQT2, and 62 with LQT3 mutations).
I
Intervention
LQT1 or LQT2 genotype
C
Comparator
LQT3 genotype
O
Outcome
Cumulative probability and lethality of cardiac events (syncope, aborted cardiac arrest, or sudden death) occurring from birth through the age of 40 yearshard clinical
Main Result
Absolute Event Rate: 63% vs 18%
p-value: p=<0.001
The genotype of congenital long-QT syndrome significantly influences its clinical course, with LQT1 and LQT2 patients experiencing more frequent cardiac events, whereas LQT3 patients experience fewer but significantly more lethal events.
Cite This Study
Zaręba et al. (1998) conducted a cohort in Congenital long-QT syndrome (n=1,378). LQT1 or LQT2 locus mutations vs. LQT3 locus mutations was evaluated on Cardiac events (syncope, aborted cardiac arrest, or sudden death) (p=<0.001). Mutations at the LQT1 (63%) or LQT2 (46%) locus were associated with a higher frequency of cardiac events than LQT3 mutations (18%, P<0.001), though LQT3 events were more often lethal (20% vs 4%).