Stress proneness in molecularly defined long QT syndrome: a study using temperament assessment by behavioural inhibition system scale

Compound and heterozygous mutations of KCNQ1 in long QT syndrome with familial history of unexplained sudden death: Identified by analysis of whole exome sequencing and predisposing genes

Introduction

Long QT syndrome (LQTS) increases the risk of life‐threatening arrhythmia in young individuals with structurally normal hearts. Sixteen genes such as the KCNQ1, KCNH2, and SCN5A have been reported for association with LQTS.

Case presentation

We identified the compound heterozygous mutations in the KCNQ1 gene at c. G527A (p.W176X) and c.G1765A (p.G589S) predicted as “damaging.” The in‐silico analysis showed that when compared to the characteristics of mRNA and protein of wild‐type KCNQ1, the mRNA of c.G527A mutation was significantly different in the centroid secondary structure. The subunit coded by W176X would lose the transmembrane domains S3–S6 and helices A‐D. The protein secondary structure of G589S was slightly shortened in helix structure; the protein physics‐chemical parameters of W176X and G589S significantly and slightly changed, respectively.

Conclusions

The compound heterozygous mutations of W176X and G589S coexisting in KCNQ1 gene of homologous chromosomes, resulting in more severe phenotype, are the likely pathogenic and genetic risks of LQTS and USD in this Chinese family.

Type 1 long QT syndrome and psychological stress in a laboratory setting

Trait-like sensitivity to stress in long QT syndrome patients has been documented previously. In addition, mental stress has been associated with symptomatic status of long QT syndrome. We examined whether the symptomatic type 1 long QT syndrome patients would be more sensitive to mental stress compared to asymptomatic patients and whether there would be differences in task-related physiological stress reactions between type 1 long QT syndrome patients and healthy individuals. The study population consisted of 21 symptomatic and 23 asymptomatic molecularly defined KCNQ1 mutation carriers, their 32 non-carrier relatives and 46 non-related healthy controls, with mean ages of 37, 39, 35 and 23 years, respectively. Electrocardiography was utilised to calculate inter-beat interval and high frequency and low frequency heart rate variability. Blood pressure was measured and mean arterial pressure and pulse pressure were calculated. Stress was induced using three different tasks: mental arithmetic, reaction time and public speech. Stress responses of symptomatic and asymptomatic type 1 long QT syndrome patients were not statistically different in any of the stress tasks. Short-term physiological stress reactivity of symptomatic type 1 long QT syndrome patients appears to be normal and does not enhance the risk assessment of asymptomatic mutation carriers.

Is Symptomatic Long QT Syndrome Associated with Depression in Women and Men?

We examined whether long QT syndrome (LQTS) mutation carrier status or symptomatic LQTS are associated with depression, and whether there are sex differences in these potential relationships. The sample comprised 782 participants (252 men). Of the 369 genetically defined LQTS mutation carriers, 169 were symptomatic and 200 were asymptomatic. The control group consisted of 413 unaffected relatives. Depression was assessed using the Beck Depression Inventory-II (BDI-II). No association was found for LQTS mutation carrier status with depression. The multinomial logistic regression showed that LQTS mutation carrier men with arrhythmic events scored higher on depression compared with the control group, even when adjusting for age, β-blockers, antidepressants, and social support (OR = 1.09, 95 % CI [1.02, 1.15], p = .007). The binary logistic regression comparing symptomatic and asymptomatic LQTS mutation carriers showed that symptomatic LQTS was associated with depression in men (OR = 1.10, 95 % CI [1.03, 1.19], p = .009). The results were unchanged when additionally adjusted for education. These findings suggest that symptomatic LQTS is associated with depression in men but not in women. Overall, however, depression is more frequent in women than men. Thus, regular screening for depression in LQTS mutation carriers and their unaffected family members can be important.

Sudden cardiac death with stress and restraint: The association with sudden adult death syndrome, cardiomyopathy and coronary artery disease

OBJECTIVE

The aim of this study was to report on sudden cardiac death (SCD) during or immediately after a stressful event in a predominately young cohort.

METHODS

This study used retrospective non-case-controlled analysis. A total of 110 cases of SCD in relation to a stressful event such as altercation (45%), physical restraint (31%) in police custody (10%), exams/school/job stress (7.27%), receiving bad news (4%), or a car accident without injuries (2.73%) were retrospectively investigated. The majority of the subjects experiencing SCD were male (80.91%). The mean age was 36 ± 16 years (range 5-82 years). Twenty-three cases (20.91%) were psychiatric patients on antipsychotic medication.

RESULTS

Fifty-three per cent of cases died with a negative autopsy and a morphologically normal heart, indicating sudden adult death which is linked to cardiac channelopathies predisposing to stress-induced SCD. Cardiomyopathy was found in 16 (14.5%) patients and coronary artery pathology in 19 (17%) patients, with atherosclerosis predominating in older patients.

CONCLUSIONS

This study highlights SCD during psychological stress, mostly in young males where the sudden death occurred in the absence of structural heart disease. This may reflect the proarrhythmic potential of high catecholamines on the structurally normal heart in those genetically predisposed because of cardiac channelopathy. Structural cardiomyopathies and coronary artery disease also feature prominently. Cases of SCD associated with altercation and restraint receive mass media attention especially when police/other governmental bodies are involved. This study highlights the rare but important risk of SCD associated with psychological stress and restraint in morphologically normal hearts and the importance of an expert cardiac opinion where prolonged criminal investigations and medico-legal issues often ensue.

Brief report: Emotional distress and recent stressful life events in long QT syndrome mutation carriers

To study emotional distress in symptomatic and asymptomatic long QT syndrome mutation carriers who had experienced a recent stressful life event. The participants were 209 symptomatic and 279 asymptomatic long QT syndrome mutation carriers. Emotional distress was assessed with the Cope questionnaire and stressful life events with the Social Readjustment Rating Scale. Symptomatic long QT syndrome mutation carriers with burdening recent stressful life events reported a higher emotional distress (β = 0.35, p < 0.001), while the asymptomatic did not show such difference (β = 0.13, p = 0.393). Symptomatic long QT syndrome mutation carriers who have experienced stressful life events recently report an increased emotional distress.