Vol 4, No 2 (2024)
- Year: 2024
- Articles: 4
- URL: https://journals.rcsi.science/cardar/issue/view/17442
- DOI: https://doi.org/10.17816/cardar.42
Original Research
Unexplained cardiac arrest (idiopathic ventricular fibrillation): clinical and genetic characteristics
Abstract
AIM: The study was to evaluate the clinical and genetic characteristics of inherited arrhythmias in patients who survived unexplained cardiac arrest.
MATERIALS AND METHODS: 20 patients (10 male and 10 female) aged 15 to 55 years (median age 36 [28; 44] years) with documented VT/VF on ECG were observed for 3 years. The clinical and instrumental study included registration of 12-lead ECG, 24-hour Holter ECG, genealogical history collection and family history of sudden cardiac death with ECG assessment of all family members, transthoracic echocardiography, 2D Speckle Tracking echocardiography and cardiac magnetic resonance imaging to exclude structural myocardial changes. High-throughput sequencing (NGS) was utilized to search for mutations in genes linked to the onset of channelopathies and other inherited rhythm disorders.
RESULTS: In 4 (20 %) of the 20 probands included in the study, likely pathogenic variants were identified (pathogenicity class IV), and in 7 (35 %) patients, variants with unknown clinical significance (pathogenicity class III) in 10 genes associated with channelopathies (KCNQ1, KCNH2, SCN5A, AKAP9, ANK2, SCN10А, RYR2) and cardiomyopathies (MYH7, JPH2, RBM20). Several genetic variants were found in 3 cases. No significant genetic changes were detected in 9 (45 %) probands. The clinical diagnosis was established during the follow-up period and was verified due to the genetic testing in 5 (25 %) patients. From their ECGs, a prolonged QTc > 460 ms was found in 1 patient, Brugada pattern in 2 individuals, and a shortening of QTc up to 323 ms in 1 proband. Subclinical structural changes associated with cardiomyopathies were revealed in 2 patients. In 15 (75 %) patients, it was unfeasible to establish a distinct clinical phenotype. In 6 (30 %) probands, the diagnosis was clarified due to detected genetic variants.
CONCLUSION: Clinical manifestations and diverse genetic variants have been studied in patients who have survived unexplained cardiac arrest. In the course of genotyping patients who suffered unexplained cardiac arrest, genetic changes associated with LQTS were detected in 30 % of cases, while the QTc in most cases did not exceed 440 ms, which makes it difficult to establish a diagnosis at an early stage before the development of life-threatening arrhythmic events. The data from our study confirm the idea that in patients with idiopathic ventricular fibrillation, who have suffered unexplained cardiac arrest, cardiac channelopathy or subclinical manifestations of cardiomyopathy are commonly the cause. This phenomenon imposes a need for genetic testing in this category of patients.
5-18
Genetic markers and traditional risk factors in predicting atrial fibrillation in patients with arterial hypertension, focus on the renin-angiotensin-aldosterone system genes
Abstract
BACKGROUND: Genetic and environmental factors are involved in the development of atrial fibrillation in arterial hypertension. This determines the relevance of studying gene-environment interactions in the occurrence of arrhythmia.
AIM: To evaluate the contribution of the renin-angiotensin-aldosterone system genes polymorphisms to the susceptibility to atrial fibrillation in patients with arterial hypertension, and also to study the combined influence of these polymorphisms and environmental factors on the risk of arrhythmia.
MATERIALS AND METHODS: The study included 60 patients with arterial hypertension and paroxysmal atrial fibrillation (study group), 60 patients with arterial hypertension without atrial fibrillation (comparison group-1) and 20 healthy volunteers (comparison group-2). Angiotensin-converting enzyme (ACE (I/D)) and angiotensin II type 1 receptor gene (AGTR1 (A1166C)) polymorphisms were analyzed by real-time polymerase chain reaction.
RESULTS: Genotype II and allele I of the ACE gene (I/D) in patients with arterial hypertension and atrial fibrillation were significantly more frequent compared to patients with arterial hypertension without arrhythmia (χ² = 4.547; p = 0.03 and χ² = 4.818; p = 0.03 respectively). Carriage of genotype II in patients with arterial hypertension increased the chance of developing atrial fibrillation by 2.8 times (95% CI 1.19–7.18). The odds ratio (OR) for arrythmia development in patients with arterial hypertension and allele I was 1.8 (95% CI 1.10–3.07). The presence of obesity in patients with arterial hypertension in the presence of genotype II of the ACE gene (I/D) was associated with an increased risk of developing atrial fibrillation, compared with the genotype alone (OR = 4.16, 95% CI 1.16–19.87). A study of the A1166C polymorphism of the AGTR1 gene did not reveal a reliable significant relationship between its inheritance and the development of atrial fibrillation.
CONCLUSION: Genotype II and allele I of the ACE gene (I/D) were statistically significantly more frequent in patients with arterial hypertension and atrial fibrillation. Carriage of genotype II and allele I of the ACE gene (I/D) increased the chance of developing atrial fibrillation in patients with arterial hypertension. Obesity had a significant effect on the susceptibility to atrial fibrillation in the presence of genotype II of the ACE gene (I/D) in hypertensive patients.
19-28
Case reports
An arrhythmic variant of the manifestation of paraneoplastic Loeffler endomyocarditis. Clinical case
Abstract
A clinical case of chronic undulating course of parneoplastic Loeffler endomyocarditis, the leading manifestations of which were ventricular arrhythmias, is presented. The paper demonstrates the complexity of early diagnosis of a rare pathology in a polymorbid patient and attempts to identify the "keys" to the correct diagnostic and therapeutic tactics for managing such patients.
29-40
Clinical case of successful treatment of focal ventricular arrhythmia in a patient with arrhythmogenic mitral valve prolapse
Abstract
The problem of managing of patients with mitral valve prolapse and ventricular arrhythmias — arrhythmogenic mitral valve prolapse — is quite relevant in routine clinical practice, which led to the creation in 2022 of an expert consensuses on the management of such patients. Based on the criteria, it is possible to identify a group of people at high risk of sudden cardiac death and implement measures to prevent death. How to manage patients at moderate risk of sudden cardiac death remains unclear. A clinical case of successful treatment of ventricular arrhythmias in a patient with arrhythmogenic mitral valve prolapse is presented.
41-50