T-peak to T-end interval may be a better predictor of high-risk patients with hypertrophic cardiomyopathy associated with a cardiac troponin I mutation than QT dispersion.
BACKGROUND
Patients with hypertrophic cardiomyopathy (HCM) associated with a deletion of lysine 183 (K183del) in the cardiac troponin I (cTnI) gene suffer sudden cardiac death at all ages. However, the correlation between QT variables and sudden cardiac death in these patients remains uncertain.


OBJECTIVE
We evaluated the correlation between QT variables and sudden cardiac death and/or ventricular tachyarrhythmia (SCD/VT) in patients with HCM associated with the cTnI mutation.


METHODS
We analyzed 10 probands with HCM associated with the cTnI gene K183del and their family members. The subjects were divided into three groups: Group A (n = 7), mutation carriers with SCD/VT; Group B (n = 16), mutation carriers without SCD/VT; Group C (n = 24), no mutation carriers. QT intervals were corrected using Bazett's formula.


RESULTS
Maximum QTc and corrected QT dispersion were significantly longer in Groups A and B than in Group C. However, there were no differences in either parameter between Groups A and B. On the contrary, the peak-to-end interval of T wave/QT interval in V5 (Tpe) in Group A was significantly longer than that in Groups B and C. Logistic regression analysis revealed that Tpe was a good clinical predictor for SCD/VT in patients with HCM in this study.


CONCLUSIONS
These results suggest that Tpe rather than QT dispersion may be one of the best predictors for SCD/VT in patients with HCM associated with the K183del mutation in the cTnI gene.
Shimizu
Masami
M
Division of Cardiovascular Medicine, Graduate School of Medical Science, Kanazawa University, Japan. shimizu@med.kanazawa-u.ac.jp
Ino
Hidekazu
H
Okeie
Kazuyasu
K
Yamaguchi
Masato
M
Nagata
Mitsuru
M
Hayashi
Kenshi
K
Itoh
Hideki
H
Iwaki
Taku
T
Oe
Kotaro
K
Konno
Tetsuo
T
Mabuchi
Hiroshi
H
D000328:Adult; D000704:Analysis of Variance; D002312:Cardiomyopathy, Hypertrophic / Q000235:genetics* / Q000503:physiopathology; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011237:Predictive Value of Tests; D012307:Risk Factors; D017180:Tachycardia, Ventricular / Q000235:genetics*; D019210:Troponin I / Q000235:genetics*
D019210:Troponin I