Percutaneous left atrial appendage occlusion: impact on left atrial deformation indices.

Background: Percutaneous left atrial appendage occlusion (LAAO) is an accepted alternative to thromboprophylaxis in patients with atrial fibrillation (AF) who are: (i) intolerant to oral anticoagulation (OAC) (e.g. life-threatening haemorrhage), (ii) non-adherent to OAC, or (iii) at a high bleeding risk with OAC.

Diagnostic performance of dobutamine stress echocardiography: A South African experience.

Dobutamine stress echocardiography (DSE) is a well-established modality for the diagnosis of coronary artery disease, but there are no reported diagnostic data in southern Africa. Objectives. To compare the safety, sensitivity and specificity of a South African (SA) DSE programme with larger, international series.

Renal denervation prevents subclinical atrial fibrillation in patients with hypertensive heart disease: Randomized, sham-controlled trial.

Background: Catheter-based renal denervation (RD), in addition to pulmonary vein isolation (PVI), reduces atrial fibrillation (AF) recurrence in hypertensive patients. Whether RD, without additional PVI, can prevent subclinical atrial fibrillation (SAF) in patients with hypertensive heart disease (HHD) is unknown.

Objective: The purpose of this study was to assess the efficacy of RD in preventing SAF in patients with HHD.

Percutaneous left atrial appendage occlusion: A South African experience.

Background: Atrial fibrillation (AF) is associated with all-cause mortality, heart failure and non-fatal stroke, and thromboprophylaxis is traditionally provided with oral anticoagulants (OACs). Percutaneous left atrial appendage occlusion (LAAO) with a dedicated device is an alternative approach to thromboprophylaxis in patients with AF who are: (i) intolerant to OACs (e.g.

Mutation location and IKs regulation in the arrhythmic risk of long QT syndrome type 1: the importance of the KCNQ1 S6 region.

Aims: Mutation type, location, dominant-negative IKs reduction, and possibly loss of cyclic adenosine monophosphate (cAMP)-dependent IKs stimulation via protein kinase A (PKA) influence the clinical severity of long QT syndrome type 1 (LQT1). Given the malignancy of KCNQ1-p.A341V, we assessed whether mutations neighbouring p.

Renal Denervation in High-risk Patients with Hypertension.

Hypertension is a common health problem, which leads to a substantial mortality and morbidity burden, globally. The management of patients with high-risk and treatment-resistant hypertension remains a major clinical challenge to the treating physician. Renal denervation (RD) is an emerging technique, comprising modification of the renal sympathetic nerve supply which courses around the renal arteries.

Renal denervation: dark past, bright future?

The purpose of this review is to update the reader on the relevance of autonomic nervous system imbalance in clinical cardiology. Increased sympathetic tone associates with the metabolic syndrome, hypertension and cardiac arrhythmias. With the kidneys playing a pivotal role in increased peripheral resistance, sodium and water retention and other mechanisms, renal denervation (RD) may theoretically restore autonomic imbalance and improve cardiovascular outcomes.

Genetic Modifiers for the Long-QT Syndrome: How Important Is the Role of Variants in the 3' Untranslated Region of KCNQ1?

Background: Long-QT syndrome is an inherited cardiac channelopathy characterized by delayed repolarization, risk of life-threatening arrhythmia, and significant clinical variability even within families. Three single-nucleotide polymorphisms (SNPs) in the 3' untranslated region of KCNQ1 were recently suggested to be associated with suppressed gene expression and hence decreased disease severity when located on the same haplotype with a disease-causing KCNQ1 mutation. We sought to replicate this finding in a larger and a genetically more homogeneous population of KCNQ1 mutation carriers.

First reported cases: renal denervation with second-generation multi-electrode catheter via brachial and radial access.

Renal denervation is a minimally invasive procedure that aims to reduce brain-kidney sympathetic cross-talk. Despite the negative results of the recent SYMPLICITY HTN-3 trial, the procedure is considered safe and has been associated with many beneficial effects, including the reversal of hypertensive heart disease substrate and the prevention of cardiac arrhythmia. The first-generation radiofrequency catheter system featured a monopolar catheter that required sequential singlepoint energy application, followed by rotation, partial withdrawal of the catheter and re-application of energy.

QTc prolongation prior to angiography predicts poor outcome and associates significantly with lower left ventricular ejection fractions and higher left ventricular end-diastolic pressures.

Background: QT prolongation on the surface ECG is associated with sudden cardiac death. The cause of QT prolongation in ischaemic heart disease (IHD) patients remains unknown, but may be due to a complex interplay between genetic factors and impaired systolic and/or diastolic function through as yet unexplained mechanisms. It was hypothesised that QT prolongation before elective coronary angiography is associated with an increased mortality at six months.

Vagal reflexes following an exercise stress test: a simple clinical tool for gene-specific risk stratification in the long QT syndrome.

Objectives: The study assessed whether heart rate (HR) reduction following an exercise stress test (ExStrT), an easily quantifiable marker of vagal reflexes, might identify high- and low-risk long QT syndrome (LQTS) type 1 (LQT1) patients.

Background: Identification of LQTS patients more likely to be symptomatic remains elusive. We have previously shown that depressed baroreflex sensitivity, an established marker of reduced vagal reflexes, predicts low probability of symptoms among LQT1.

Genetic variation in angiotensin II type 2 receptor gene influences extent of left ventricular hypertrophy in hypertrophic cardiomyopathy independent of blood pressure.

Introduction: Hypertrophic cardiomyopathy (HCM), an inherited primary cardiac disorder mostly caused by defective sarcomeric proteins, serves as a model to investigate left ventricular hypertrophy (LVH). HCM manifests extreme variability in the degree and distribution of LVH, even in patients with the same causal mutation. Genes coding for renin-angiotensin-aldosterone system components have been studied as hypertrophy modifiers in HCM, with emphasis on the angiotensin (Ang) II type 1 receptor (AT(1)R).

Abnormal blood pressure response to exercise occurs more frequently in hypertrophic cardiomyopathy patients with the R92W troponin T mutation than in those with myosin mutations.

Abnormal blood pressure response to exercise is reported to occur in up to a third of hypertrophic cardiomyopathy (HCM) cases and is associated with an increased risk of death, particularly in the young, but it is not known whether the HCM-causing mutation influences blood pressure response to exercise. The purpose of this article is to ascertain whether the blood pressure response to exercise differs among carriers of the R92W mutation in the cardiac troponin T gene (TNNT2), which has been associated with an increased risk of sudden cardiac death in young males; carriers of mutations in the cardiac beta-myosin heavy chain gene (MYH7); and their noncarrier relatives. Thirty R92W(TNNT2) carriers, 51 MYH7 mutation carriers, and 68 of their noncarrier relatives were subjected to bicycle ergonometric exercise testing to assess blood pressure response to, as well as heart rate recovery after, exercise.

Genetic variation in angiotensin-converting enzyme 2 gene is associated with extent of left ventricular hypertrophy in hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy, a common, inherited cardiac muscle disease, is primarily caused by mutations in sarcomeric protein-encoding genes and is characterized by overgrowth of ventricular muscle that is highly variable in extent and location. This variability has been partially attributed to locus and allelic heterogeneity of the disease-causing gene, but other factors, including unknown genetic factors, also modulate the extent of hypertrophy that develops in response to the defective sarcomeric functioning. Components of the renin-angiotensin-aldosterone system are plausible candidate hypertrophy modifiers because of their role in controlling blood pressure and biological effects on cardiomyocyte hypertrophy.

Neural control of heart rate is an arrhythmia risk modifier in long QT syndrome.

Objectives: The purpose of this study was to test the hypothesis that differences in autonomic responses might modify clinical severity in long QT syndrome type 1 (LQT1) patients, those with KCNQ1 mutations and reduced I(Ks), in whom the main arrhythmia trigger is sympathetic activation.

Background: Some long QT syndrome (LQTS) patients experience life-threatening cardiac arrhythmias, whereas others remain asymptomatic throughout life. This clinical heterogeneity is currently unexplained.

Troponin T and beta-myosin mutations have distinct cardiac functional effects in hypertrophic cardiomyopathy patients without hypertrophy.

Aims: The validity of genotype:phenotype correlation studies in human hypertrophic cardiomyopathy (HCM) has recently been questioned, yet animal models and in vitro studies suggest distinct effects for different mutations. The aims of this study were to investigate whether distinct HCM-mutations have different consequences for cardiac structure and function in the absence of the confounding effects of hypertrophy.

Methods And Results: Individuals aged 20-65 belonging to 21 R92W(TNNT2), R403W(MYH7), or A797T(MYH7) mutation-bearing families were investigated with 2D, M-mode, and Doppler echocardiography.

Race and gender representation of hypertrophic cardiomyopathy or long QT syndrome cases in a South African research setting.

We researched hypertrophic cardiomyopathy (HCM) and long QT syndrome (LQTS) as models for studying the pathophysiology of arrhythmias and hypertrophy, and in the process we have had the opportunity to compare local disease profiles with global patterns. We trawled our database entries over the past 20 years to identify all cases of heart muscle and arrhythmic disease. Among these, we separated the index cases from the rest of their family members, segregating for the relevant heart disease, so that numbers were not biased by family size, and analysed the race and gender composition of the HCM and LQTS sectors.

Long-term follow-up of R403WMYH7 and R92WTNNT2 HCM families: mutations determine left ventricular dimensions but not wall thickness during disease progression.

Background: The clinical profile and prognosis of patients with hypertrophic cardiomyopathy, a primary cardiac muscle disease caused mostly by mutations in sarcomeric protein-encoding genes, have been linked to particular disease-causing mutations in the past. However, such associations are often based on cross-sectional observations, as longitudinal studies of the progression of the disease in genotypically defined patients are sparse. Most importantly, the relative contribution of age, gender and genetic cause to disease profile and progression has not yet been reported, and the question remains whether one or more of these factors could mask the effect of the other(s).

Does pregnancy increase cardiac risk for LQT1 patients with the KCNQ1-A341V mutation?

Objectives: The purpose of this study was to assess the pregnancy-related cardiovascular risk in LQT1 patients.

Background: Only 1 study addressed this issue in genotyped patients and reported that the highest risk is for LQT2 patients.

Methods: This case-control study, performed in a cohort of patients from 22 families affected by LQT1 and all sharing the common KCNQ1-A341V mutation, involved 36 mutation carriers and 24 of their unaffected sisters for a total of 182 pregnancies.

Phenotypic variability and unusual clinical severity of congenital long-QT syndrome in a founder population.

Background: In the congenital long-QT syndrome (LQTS), there can be a marked phenotypic heterogeneity. Founder effects, by which many individuals share a mutation identical by descent, represent a powerful tool to further understand the underlying mechanisms and to predict the natural history of mutation-associated effects. We are investigating one such founder effect, originating in South Africa in approximately ad 1700 and segregating the same KCNQ1 mutation (A341V).