Noninvasive assessment of myocardial fibrosis in patients with obstructive hypertrophic cardiomyopathy.

Objective: Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging is the reference standard for non-invasive assessment of fibrosis. In hypertrophic cardiomyopathy (HCM) patients the histological substrate for LGE is still unknown. The aim of this study was to assess the ability of LGE and strain echocardiography to detect type and extent of myocardial fibrosis in obstructive HCM patients undergoing septal myectomy.

Abnormal electroencephalograms in patients with long QT syndrome.

Background: The long QT syndrome (LQTS) is an inherited cardiac channelopathy associated with syncope and sudden cardiac death due to ventricular arrhythmias. It is most frequently caused by potassium channel mutations. Potassium channels are also expressed in brain tissue and play an important role in idiopathic epilepsies.

The Wedensky test predicts malignant ventricular arrhythmias after myocardial infarction.

Objectives: Better tools are needed for detection of future malignant ventricular arrhythmias post myocardial infarct (MI). Wedensky Modulation (WM) is a new semi-invasive method: A short low-amplitude electrical impulse is applied synchronized to the QRS between a precordial and dorsal thoracic patch, and changes in the following QRS-T are registered.

Design: A total of 357 (MI) ICD patients underwent WM testing.

Increased amount of interstitial fibrosis predicts ventricular arrhythmias, and is associated with reduced myocardial septal function in patients with obstructive hypertrophic cardiomyopathy.

Aims: Reduced echocardiographic strain is associated with ventricular arrhythmias in hypertrophic cardiomyopathy (HCM) patients. The aim of this cross-sectional study was to investigate which type of histological fibrosis contributes to ventricular arrhythmias and reduced septal longitudinal strain, in obstructive HCM-patients with or without additional coronary artery disease (CAD) and/or hypertension (HT).

Methods And Results: Sixty-three HCM-patients (mean age 57 ± 13 years) were included.

Signal-averaged and standard electrocardiography in patients with newly diagnosed epilepsy.

Antiepileptic drugs (AEDs) have been associated with cardiac conduction abnormalities and arrhythmias, predominantly in patients with predisposing cardiac conditions. Ventricular late potentials (VLPs) detected in the signal-averaged electrocardiogram (SAECG) may imply an increased risk of ventricular tachycardia or fibrillation. Twenty-six AED-naïve patients with newly diagnosed epilepsy and no clinical evidence of heart disease were examined with SAECG and standard ECG.

High-intensity interval training improves peak oxygen uptake and muscular exercise capacity in heart transplant recipients.

Heart transplant (HTx) recipients usually have reduced exercise capacity with reported VO(2peak) levels of 50-70% predicted value. Our hypothesis was that high-intensity interval training (HIIT) is an applicable and safe form of exercise in HTx recipients and that it would markedly improve VO(2peak.) Secondarily, we wanted to evaluate central and peripheral mechanisms behind a potential VO(2peak) increase.

The terminal part of the QT interval (T peak to T end): a predictor of mortality after acute myocardial infarction.

Background: The terminal part of the QT interval (T peak to T end; Tp-e)-an index for dispersion of cardiac repolarization-is often prolonged in patients experiencing malignant ventricular arrhythmias after acute myocardial infarction (AMI). We wanted to explore whether high Tp-e might predict mortality or fatal arrhythmia post-AMI.

Methods: Tp-e was measured prospectively in 1359/1384 (98.

Prediction of life-threatening arrhythmias--still an unresolved problem.

A major challenge in current cardiology is to predict who will die suddenly from ventricular arrhythmias. Ventricular arrhythmias are the most common cause of sudden cardiac death, occurring in about 1-2:1,000 inhabitants yearly, and is most frequently due to coronary artery disease. Patients with increased risk of ventricular arrhythmias can be offered medical treatment and ultimately an implantable cardioverter defibrillator (ICD).

Long-term outcome of percutaneous transluminal septal myocardial ablation in hypertrophic obstructive cardiomyopathy: a Scandinavian multicenter study.

Background: Single-center reports on percutaneous transluminal septal myocardial ablation (PTSMA) in patients with hypertrophic obstructive cardiomyopathy have shown considerable differences in outcome.

Methods And Results: We report the long-term outcome of 313 PTSMA procedures performed in 279 patients with hypertrophic obstructive cardiomyopathy aged 59±14 years from 1999 to 2010 in 4 Scandinavian centers. Sixty-nine percent of patients had ≥1 comorbidity at baseline.

Right ventricular mechanical dispersion is related to malignant arrhythmias: a study of patients with arrhythmogenic right ventricular cardiomyopathy and subclinical right ventricular dysfunction.

Aims: We evaluated if right ventricular (RV) mechanical dispersion by strain was related to ventricular arrhythmias (VT/VF) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and if mechanical dispersion was increased in so far asymptomatic mutation carriers.

Methods And Results: We included 69 patients, 42 had symptomatic ARVC and 27 were mutation positive asymptomatic family members. Forty healthy individuals served as controls.

Transmural differences in myocardial contraction in long-QT syndrome: mechanical consequences of ion channel dysfunction.

Background: Long-QT syndrome (LQTS) is characterized by prolonged myocardial action potential duration. The longest action potential duration is reported in the endomyocardium and midmyocardium. Prolonged action potential duration in LQTS may cause prolonged cardiac contraction, which can be assessed by strain echocardiography.

Mechanical dispersion assessed by myocardial strain in patients after myocardial infarction for risk prediction of ventricular arrhythmia.

Objectives: The aim of this study was to investigate whether myocardial strain echocardiography can predict ventricular arrhythmias in patients after myocardial infarction (MI).

Background: Left ventricular (LV) ejection fraction (EF) is insufficient for selecting patients for implantable cardioverter-defibrillator (ICD) therapy after MI. Electrical dispersion in infarcted myocardium facilitates malignant arrhythmia.

[Catecholaminergic polymorphic ventricular tachycardia].

Background: CPVT (catecholaminergic polymorphic ventricular tachycardia) is a condition characterized by syncopes and cardiac arrest that was first described in 1975. CPVT has later been classified as a genetic disease with a great risk for life-threatening arrhythmias that are mainly caused by mutations in the ryanodine receptor 2 gene. Starting with a case report, we present an overview of CPVT.

High prevalence of exercise-induced arrhythmias in catecholaminergic polymorphic ventricular tachycardia mutation-positive family members diagnosed by cascade genetic screening.

Aim: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited cardiac disease predisposing to life-threatening arrhythmias. We aimed to determine the prevalence of arrhythmias and efficacy of beta-blocker treatment in mutation-positive family members diagnosed by cascade genetic screening.

Methods And Results: Relatives of six unrelated CPVT patients were tested for the relevant mutation in the ryanodine receptor-2 gene.

Cardiac function and antiepileptic drug treatment in the elderly: a comparison between lamotrigine and sustained-release carbamazepine.

Purpose: To investigate the comparative effects of carbamazepine (CBZ) and lamotrigine (LTG) on electrocardiography (ECG) parameters in elderly patients with newly diagnosed epilepsy.

Methods: The study was conducted in the Norwegian subcohort (n = 108) of an international randomized double-blind 40-week trial, which compared the efficacy and tolerability of LTG and sustained-release CBZ in patients aged 65 and older with newly diagnosed epilepsy. Target maintenance doses were 400 mg/day for CBZ and 100 mg/day for LTG, with adjustments based on clinical response.

Genetic testing in specific cardiomyopathies.

An increasing number of genetic tests for cardiomyopathies are becoming available for clinical use. This commentary will give a short overview of indications and challenges concerning genetic testing for these conditions.

Left ventricular mechanical dispersion by tissue Doppler imaging: a novel approach for identifying high-risk individuals with long QT syndrome.

Aims: The aim of this study was to investigate whether prolonged and dispersed myocardial contraction duration assessed by tissue Doppler imaging (TDI) may serve as risk markers for cardiac events (documented arrhythmia, syncope, and cardiac arrest) in patients with long QT syndrome (LQTS).

Methods And Results: Seventy-three patients with genetically confirmed LQTS (nine double- and 33 single-mutation carriers with previous cardiac events and 31 single-mutation carriers without events) were studied. Myocardial contraction duration was prolonged in each group of LQTS patients compared with 20 healthy controls (P < 0.

Molecular genetic analysis of long QT syndrome in Norway indicating a high prevalence of heterozygous mutation carriers.

Mutations in the KCNQ1, HERG, SCN5A, minK and MiRP1 genes cause long QT syndrome (LQTS), of which there are two forms: the Romano Ward syndrome and the Jervell and Lange-Nielsen syndrome. We have performed DNA sequencing of the LQTS-associated genes in 169 unrelated patients referred for genetic testing with respect to Romano Ward syndrome and in 13 unrelated patients referred for genetic testing with respect to Jervell and Lange-Nielsen syndrome. A total of 37 different mutations in the 5 genes, of which 20 were novel, were identified.

Increased mortality after dronedarone therapy for severe heart failure.

Background: Dronedarone is a novel antiarrhythmic drug with electrophysiological properties that are similar to those of amiodarone, but it does not contain iodine and thus does not cause iodine-related adverse reactions. Therefore, it may be of value in the treatment of patients with heart failure.

Methods: In a multicenter study with a double-blind design, we planned to randomly assign 1000 patients who were hospitalized with symptomatic heart failure and severe left ventricular systolic dysfunction to receive 400 mg of dronedarone twice a day or placebo.

Sympathetic predominance of cardiovascular regulation during mild orthostatic stress in adolescents with chronic fatigue.

Haemodynamic abnormalities have been documented in the chronic fatigue syndrome (CFS), indicating functional disturbances of the autonomic nervous system responsible for cardiovascular control. This study was designed to explore the pathophysiology in adolescent CFS-patients by analysing RR-interval (RRI) variability and diastolic blood pressure (DBP) variability during mild orthostatic stress, using an algorithm which accounts for non-stationary biosignals. A total of 27 adolescents with CFS and 33 healthy control subjects having equal age- and sex distribution underwent 15 min of 20 degrees head-up tilt (HUT).

Treatment of chronic fatigue and orthostatic intolerance with propranolol.

We describe the effect of propranolol in an adolescent with chronic fatigue syndrome and orthostatic intolerance. Our observations suggest that the head-up tilt-test and beta-blocker treatment might be considered in patients with chronic fatigue syndrome and that enhanced sympathetic nervous activity might be part of the underlying pathophysiology.

Usefulness of an abnormal cardiovascular response during low-grade head-up tilt-test for discriminating adolescents with chronic fatigue from healthy controls.

Hemodynamic dysfunction is documented in chronic fatigue syndrome (CFS). This study was conducted to investigate cardiovascular responses to orthostatic stress in adolescents with CFS, using a novel procedure for tilt-table testing. A total of 27 adolescents with CFS and 33 healthy control subjects with equal age and gender distribution underwent 15 minutes of 20 degrees head-up tilt testing.