AimsHypertrophic cardiomyopathy (HCM) patients are at risk of ventricular arrhythmias (VAs). We aimed to explore whether systolic function by strain echocardiography is related to VAs and to the extent of fibrosis by cardiac magnetic resonance imaging (CMR).Methods and resultsWe included 150 HCM patients and 50 healthy individuals. VAs were defined as non-sustained and sustained ventricular tachycardia and aborted cardiac arrest. Left ventricular function was assessed by ejection fraction (EF) and by global longitudinal strain (GLS) assessed by speckle tracking echocardiography. Mechanical dispersion was calculated as standard deviation (SD) of time from Q/R on ECG to peak longitudinal strain in 16 left ventricular segments. Late gadolinium enhancement (LGE) was assessed by CMR. HCM patients had similar EF (61 ± 5% vs. 61 ± 8%, P = 0.77), but worse GLS (−15.7 ± 3.6% vs. −21.1 ± 1.9%, P < 0.001) and more pronounced mechanical dispersion (64 ± 22 vs. 36 ± 13 ms, P < 0.001) compared with healthy individuals. VAs were documented in 37 (25%) HCM patients. Patients with VAs had worse GLS (−14.1 ± 3.6% vs. −16.3 ± 3.4%, P < 0.01), more pronounced mechanical dispersion (79 ± 27 vs. 59 ± 16 ms, P < 0.001), and higher %LGE (6.1 ± 7.8% vs. 0.5 ± 1.4%, P < 0.001) than patients without VAs. Mechanical dispersion correlated with %LGE (R = 0.52, P < 0.001) and was independently associated with VAs (OR 1.6, 95% CI 1.1–2.3, P = 0.02) and improved risk stratification for VAs.ConclusionGLS, mechanical dispersion, and LGE were markers of VAs in HCM patients. Mechanical dispersion was a strong independent predictor of VAs and related to the extent of fibrosis. Strain echocardiography may improve risk stratification of VAs in HCM.

AimsWe evaluated if a dispersed left atrial (LA) contraction pattern was related to atrial fibrillation (AF) in patients with normal left ventricular (LV) function, and normal or mildly enlarged left atrium.Methods and resultsWe included 61 patients with paroxysmal AF (PAF). Of these, 30 had not while 31 had recurrence of AF after radiofrequency ablation (RFA). Twenty healthy individuals were included for comparison. Echocardiography was performed in patients in sinus rhythm the day before RFA. LA volume was calculated. Peak negative longitudinal strain was assessed in 18 LA segments during atrial systole. Contraction duration in 18 LA segments was measured as the time from peak of the P wave on electrocardiogram to maximum myocardial shortening in each segment. The standard deviation of contraction durations was defined as LA mechanical dispersion (LA MD). LA size was rather preserved in patients with PAF (LA volume 25 ± 10 mL/m2). LA MD was more pronounced in patients with recurrence of AF after RFA compared with those without recurrence and controls (38 ± 14 ms vs. 30 ± 12 ms vs. 16 ± 8 ms, both P < 0.001). LA MD was a predictor of PAF [OR 7.84 (95%CI 2.15–28.7), P < 0.01, per 10 ms increase] adjusted for age, LA volume, e’, and LA function. LA function by strain was reduced in both patients with and without recurrent AF after RFA compared with controls (−14 ± 4% vs. −16 ± 3% vs. −19 ± 2%, both P < 0.05).ConclusionLA MD was pronounced, and LA deformation was reduced in patients with PAF with apparently normal LV structure and function, and normal or mildly enlarged LA. LA MD may be useful as a predictor of AF recurrence after RFA.

This review aims to give an update on the pathogenesis, clinical manifestations, and diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC). Arrhythmogenic right ventricular cardiomyopathy is mainly an autosomal dominant inherited disease linked to mutations in genes encoding desmosomes or desmosome-related proteins. Classic symptoms include palpitations, cardiac syncope, and aborted cardiac arrest due to ventricular arrhythmias. Heart failure may develop in later stages. Diagnosis is based on the presence of major and minor criteria from the Task Force Criteria revised in 2010 (TFC 2010), which includes evaluation of findings from six different diagnostic categories. Based on this, patients are classified as having possible, borderline, or definite ARVC. Imaging is important in ARVC diagnosis, including both echocardiography and cardiac magnetic resonance imaging for detecting structural and functional abnormalities, but importantly these findings may occur after electrical alterations and ventricular arrhythmias. Electrocardiograms (ECGs) and signal-averaged ECGs are analysed for depolarization and repolarization abnormalities, including T-wave inversions as the most common ECG alteration. Ventricular arrhythmias are common in ARVC and are considered a major diagnostic criterion if originating from the RV inferior wall or apex. Family history of ARVC and detection of an ARVC-related mutation are included in the TFC 2010 and emphasize the importance of family screening. Electrophysiological studies are not included in the diagnostic criteria, but may be important for differential diagnosis including RV outflow tract tachycardia. Further differential diagnoses include sarcoidosis, congenital abnormalities, myocarditis, pulmonary hypertension, dilated cardiomyopathy, and athletic cardiac adaptation, which may mimic ARVC.

Subjects with LQTS had a consistent reduction in both systolic and diastolic function compared with healthy controls. Differences in myocardial function between subjects with LQT1 and subjects with LQT2 may indicate that mechanical alterations in LQTS are genotype specific.

Aims In patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), implantable cardioverter-defibrillator (ICD) shocks are sometimes ineffective and may even trigger fatal electrical storms. We assessed the efficacy and complications of ICDs placed in patients with CPVT who presented with a sentinel event of sudden cardiac arrest (SCA) while undiagnosed and therefore untreated. Methods and results We analysed 136 patients who presented with SCA and in whom CPVT was diagnosed subsequently, leading to the initiation of guideline-directed therapy, including β-blockers, flecainide, and/or left cardiac sympathetic denervation. An ICD was implanted in 79 patients (58.1%). The primary outcome of the study was sudden cardiac death (SCD). The secondary outcomes were composite outcomes of SCD, SCA, appropriate ICD shocks, and syncope. After a median follow-up of 4.8 years, SCD had occurred in three patients (3.8%) with an ICD and none of the patients without an ICD (P = 0.1). SCD, SCA, or appropriate ICD shocks occurred in 37 patients (46.8%) with an ICD and 9 patients (15.8%) without an ICD (P < 0.0001). Inappropriate ICD shocks occurred in 19 patients (24.7%) and other device-related complications in 22 patients (28.9%). Conclusion In previously undiagnosed patients with CPVT who presented with SCA, an ICD was not associated with improved survival. Instead, the ICD was associated with both a high rate of appropriate ICD shocks and inappropriate ICD shocks along with other device-related complications. Strict adherence to guideline-directed therapy without an ICD may provide adequate protection in these patients without all the potential disadvantages of an ICD.

The incidence and severity of ventricular arrhythmias decreased during treatment with nadolol compared with during treatment with β1-selective β-blockers. β1-Selective β-blockers did not change the occurrence or severity of arrhythmias compared with no medication.

History of high-intensity exercise, electrocardiographic T-wave inversions ≥V, and greater LV mechanical dispersion were strong predictors of life-threatening ventricular arrhythmia. Patients without any of these risk factors had minimal risk, whereas ≥2 risk factors increased the risk dramatically. This may help to make decisions on primary preventive implantable cardioverter defibrillator (ICD) therapy.

AimCatecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited cardiac disease predisposing to lifethreatening arrhythmias. We aimed to determine the prevalence of arrhythmias and efficacy of b-blocker treatment in mutation-positive family members diagnosed by cascade genetic screening. Methods and resultsRelatives of six unrelated CPVT patients were tested for the relevant mutation in the ryanodine receptor-2 gene. Mutation carriers underwent an exercise test at inclusion time and 3 months after the initiation of b-blocker therapy in the highest tolerable dose. The occurrence of ventricular premature beats, couplets, and non-sustained ventricular arrhythmias (nsVT) were recorded in addition to the heart rate at which they occurred. Thirty family members were mutation carriers and were followed for 22 (13 -288) months. Previous undiagnosed CPVTrelated symptoms were reported by eight subjects. Exercise test induced ventricular arrhythmias in 23 of the 30 mutation carriers. On b-blocker treatment, exercise-induced arrhythmias occurred at a lower heart rate (117 + 17 vs. 135 + 34 beats/min, P ¼ 0.02) but at similar workload (P ¼ 0.78). b-Blocker treatment suppressed the occurrence of exercise-induced nsVT in three of the four patients, while less severe arrhythmias were unchanged. One patient died during follow-up. ConclusionExercise test revealed a high prevalence of arrhythmias in CPVT mutation carriers diagnosed by cascade genetic screening. b-Blocker therapy appeared to suppress the most severe exercise-induced arrhythmias, while less severe arrhythmias occurred at a lower heart rate.--