The natural history of a genetic subtype of arrhythmogenic right ventricular cardiomyopathy caused by a p.S358L mutation in TMEM43

To determine the phenotype and natural history of a founder genetic subtype of autosomal dominant arrhythmogenic right ventricular cardiomyopathy (ARVC) caused by a p.S358L mutation in TMEM43. The age of onset of cardiac symptoms, clinical events and test abnormalities were studied in 412 subjects (258 affected and 154 unaffected), all of which occurred in affected males significantly earlier and more often than unaffected males. Affected males were hospitalized four times more often than affected females (p ≤ 0.0001) and died younger (p ≤ 0.001). The temporal sequence from symptoms onset to death was prolonged in affected females by 1–2 decades. The most prevalent electrocardiogram (ECG) manifestation was poor R wave progression (PRWP), with affected males twice as likely to develop PRWP as affected females (p ≤ 0.05). Left ventricular enlargement (LVE) occurred in 43% of affected subjects, with 11% fulfilling criteria for dilated cardiomyopathy. Ventricular ectopy on Holter monitor was common and occurred early: the most diagnostically useful clinical test. No symptom or test could rule out diagnosis. This ARVC subtype is a sex‐influenced lethal arrhythmogenic cardiomyopathy, with a unique ECG finding, LV dilatation, heart failure and early death, where molecular pre‐symptomatic diagnosis has the greatest clinical utility.     

Molecular characterization of human factor XSan Antonio

Enzymatic amplification technique was used to isolate all eight exons and sequences around the splice junctions, putative promoter, and polyadenylation sites of human factor X DNA from a patient with factor X deficiency. Two genetic changes in factor X have been observed in this patient. The patient is most likely a compound heterozygote since there is only 14% activity associated with factor X. A point mutation that resulted in the substitution of cysteine (TGC) for arginine (CGC) at amino acid 366 was found in exon VIII of one allele of the factor X gene. This mutation, which occurs in the catalytic domain, can affect the formation of a disulfide bridge and thus could result in a reduction in factor X activity. Sequencing all the regions revealed a second mutation: a deletion of one nucleotide (TCCT to TCT) in exon VII that would cause a frame shift at amino acid 272 followed by termination. We have also shown that the point mutation in exon VIII creates an ApaL1 restriction site and destroys the HinP1 site. Enzymatic DNA amplification followed by restriction digestion provides a quick, reliable, and sensitive method for carrier detection and antenatal diagnosis in affected kindreds. This is the first characterization of factor X deficiency at the molecular level. We propose to name this mutation Factor XSan Antonio.     

Activation of the coagulation cascade after infusion of a factor XI concentrate in congenitally deficient patients

Virally inactivated, high-purity factor XI concentrates are available for treatment of patients with factor XI deficiency. However, preliminary experience indicates that some preparations may be thrombogenic. We evaluated whether a highly purified concentrate produced signs of activation of the coagulation cascade in two patients with severe factor XI deficiency infused before and after surgery. Signs of heightened enzymatic activity of the common pathway of coagulation (elevated plasma levels of prothrombin fragment 1 + 2 and fibrinopeptide A) developed in the early post-infusion period, accompanied by more delayed signs of fibrin formation with secondary hyperfibrinolysis (elevated D-dimer and plasmin-antiplasmin complex). These changes occurred in both patients, but were more severe in the older patient with breast cancer when she underwent surgery, being accompanied by fibrinogen and platelet consumption. There were no concomitant signs of heightened activity of the factor VII-tissue factor mechanism on the factor Xase complex (plasma levels of activated factor VII and of factor IX and X activation peptides did not increase). The observed changes in biochemical markers of coagulation activation indicate that concentrate infusions increased thrombin generation and activity and that such changes were magnified by malignancy and surgery. Because some factor XI concentrates may be thrombogenic, they should be used with caution, especially in patients with other risk factors for thrombosis.     

Role of Chlamydia, mycoplasma and cytomegalovirus infection in the development of coronary artery disease

AIM: To assess relationship between some infection factors and presence of coronary heart disease. MATERIAL: Patients with myocardial infarction (n=56), unstable angina (n=50), stable angina (n=50) and age - matched controls (n=49). METHODS: Levels of IgG, IgM, IgA antibodies to Chlamydia pneumonia, Chlamydia trachomatis, Chlamydia psittaci, IgG, IgM antibodies to Cytomegalovirus, and also of antibodies and antigen to Mycoplasma pneumoniae were measured in blood serum. RESULTS: Compared with controls patients with coronary heart disease had higher frequency of seropositivity to Chlamydia pneumonia, Mycoplasma pneumonia and Cytomegalovirus (p< 0.05 ) and similar levels of seropositivity to Chlamydia trachomatis and Chlamydia psittaci. Infectious burden (quantity of antibodies per one patient) was significantly higher in patients with myocardial infarction, unstable and stable angina than in controls (1.58, 1.42, 1.41 and 0.95, respectively). CONCLUSION: Our results confirm presence of association between infection and coronary heart disease.     

Effect of ivabradine on pulmonary hypertension in chronic obstructive pulmonary disease

In order to assess effect of If-channel blocker ivabradine on severity of pulmonary hypertension in chronic obstructive pulmonary disease (COPD) we studied 60 patients with III-IV stage COPD. We divided these patients into 2 groups with similar clinical characteristics and therapy. Patients of one of these groups received ivabradine (10 mg/day) for 2 weeks, patients of another served as controls. The use of ivabradine was associated with statistically significant lowering of pulmonary hypertension, heart rate, and increase of exercise tolerance without negative effects on myocardial contractility, electrophysiological parameters, or data of spirometry.