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

A meta-analysis for echocardiographic assessment of right ventricular structure and function in ARVC

INTRODUCTION

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is an inherited pathology that can increase the risk of sudden death. Current Task Force Criteria for echocardiographic diagnosis do not include new, regional assessment tools which may be relevant in a phenotypically diverse disease. We adopted a systematic review and meta-analysis approach to highlight echocardiographic indices that differentiated ARVC patients and healthy controls.

METHODS

Data was extracted and analysed from prospective trials that employed a case-control design meeting strict inclusion and exclusion as well as a-priori quality criteria. Structural indices included proximal RV outflow tract(RVOT1) and RV diastolic area(RVDarea). Functional indices included RV fractional area change (RVFAC), Tricuspid Annular Systolic Excursion(TAPSE), peak systolic and early diastolic myocardial velocities (S' and E' respectively) and myocardial strain.

RESULTS

Patients with ARVC had larger RVOT1 (mean  SD; 34 vs. 28 mm P<0.001) and RVDarea (23 vs. 18 cm2 P<0.001) compared to healthy controls. ARVC patients also had lower RVFAC (38 vs. 46 % P<0.001), TAPSE(17 vs. 23 mm P<0.001), S' (9 vs. 12 cm.s-1 P<0.001), E' (9 vs. 13 cm.s-1 P<0.001) and myocardial strain (-17 vs. -30% P<0.001).

CONCLUSION

The data from this meta-analysis support current Task Force criteria for the diagnosis of ARVC. In addition, other RV measures that reflect the complex geometry and function in ARVC clearly differentiated between ARVC and healthy controls and may provide additional diagnostic and management value. We recommend that future working groups consider this data when proposing new / revised criteria for the echocardiographic diagnosis of ARVC.

Left ventricular mechanical dispersion is associated with nonsustained ventricular tachycardia in hypertrophic cardiomyopathy

OBJECTIVE

We assessed the value of speckle tracking two-dimensional (2D) strain echocardiography (2DSE) measured mechanical dispersion (MD) with other imaging and electrocardiographic parameters in differentiating hypertrophic cardiomyopathy (HCM) patients with and without nonsustained ventricular tachycardia (NSVT) on 24-h ambulatory ECG monitoring.

METHODS AND RESULTS

We studied 31 patients with HCM caused by the Finnish founder mutation MYBPC3-Q1061X and 20 control subjects with comprehensive 2DSE echocardiography and cardiac magnetic resonance imaging (CMRI). The presence of NSVT was assessed from ambulatory 24-h ECG monitoring. NSVT episodes were recorded in 11 (35%) patients with HCM. MD was significantly higher in HCM patients with NSVT (93 ± 41 ms) compared to HCM patients without NSVT (50 ± 18 ms, p = 0.012) and control subjects (41 ± 16 ms, p < 0.001). MD was the only variable independently associated with the presence of NSVT (OR: 1.60, 95% CI: 1.05-2.45, p = 0.030). Assessed by ROC curves, MD performed best in differentiating between HCM patients with and without NSVT (AUC = 0.81).

CONCLUSIONS

Increased mechanical dispersion was associated with NSVT in HCM patients on 24-h ambulatory ECG monitoring. Key messages The prediction of sudden cardiac death in hypertrophic cardiomyopathy remains a challenge and novel imaging methods are required to identify individuals at risk of malignant ventricular arrhythmias. Mechanical dispersion by speckle tracking echocardiography is associated with NSVT on 24-h ambulatory ECG monitoring in patients with hypertrophic cardiomyopathy.

Prevalence and Correlates of Early Right Ventricular Dysfunction in Sarcoidosis and Its Association with Outcome

BACKGROUND

Right ventricular (RV) function has not been systematically assessed in sarcoidosis. The aim of this study was to assess the prevalence and associates of RV dysfunction in sarcoidosis using global longitudinal peak systolic strain (GLS). Furthermore, whether RV dysfunction was associated with clinical outcomes was investigated.

METHODS

A total of 88 patients with sarcoidosis (mean age, 54 ± 13 years; 51% men) without known sarcoid-related or other structural heart disease or alternative etiologies of pulmonary hypertension were retrospectively included. RV GLS was measured using two-dimensional speckle-tracking echocardiography, and patients were stratified (using a previously defined cutoff value) as having preserved (RV GLS < -19%) or impaired (RV GLS ≥ -19%) RV function. An age- and gender-matched control group (n = 50) was included. The main outcome was all-cause mortality or clinical heart failure (hospitalization or New York Heart Association functional class ≥ III and/or deterioration by one or more classes).

RESULTS

RV GLS was significantly reduced (-20.1 ± 4.6 vs -24.6 ± 1.8%, P = .001) in patients compared with control subjects. Patients with impaired RV function (n = 41) were older and had worse pulmonary function, worse left ventricular diastolic function, and lower tricuspid annular plane systolic excursion compared with patients with preserved RV function (n = 47). Lower tricuspid annular plane systolic excursion and diabetes were independent correlates of RV GLS. Over a median follow-up period of 37 months, 19 clinical end points occurred. Patients with impaired RV function were more likely to experience the clinical end point (log-rank P = .003).

CONCLUSIONS

RV contractile dysfunction, identified using RV GLS, is common in patients with sarcoidosis without manifest cardiac involvement or pulmonary hypertension and is associated with adverse outcome. RV GLS may therefore be useful to detect sarcoidosis-related RV dysfunction at an earlier and potentially modifiable stage.

Strain echocardiographic assessment of left atrial function predicts recurrence of atrial fibrillation

AIMS

We 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 RESULTS

We 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/m(2)). 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).

CONCLUSION

LA 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.

Myocardial strain imaging: how useful is it in clinical decision making?

Myocardial strain is a principle for quantification of left ventricular (LV) function which is now feasible with speckle-tracking echocardiography. The best evaluated strain parameter is global longitudinal strain (GLS) which is more sensitive than left ventricular ejection fraction (LVEF) as a measure of systolic function, and may be used to identify sub-clinical LV dysfunction in cardiomyopathies. Furthermore, GLS is recommended as routine measurement in patients undergoing chemotherapy to detect reduction in LV function prior to fall in LVEF. Intersegmental variability in timing of peak myocardial strain has been proposed as predictor of risk of ventricular arrhythmias. Strain imaging may be applied to guide placement of the LV pacing lead in patients receiving cardiac resynchronization therapy. Strain may also be used to diagnose myocardial ischaemia, but the technology is not sufficiently standardized to be recommended as a general tool for this purpose. Peak systolic left atrial strain is a promising supplementary index of LV filling pressure. The strain imaging methodology is still undergoing development, and further clinical trials are needed to determine if clinical decisions based on strain imaging result in better outcome. With this important limitation in mind, strain may be applied clinically as a supplementary diagnostic method.

Comparison of patients with early-phase arrhythmogenic right ventricular cardiomyopathy and right ventricular outflow tract ventricular tachycardia

Aims

Differentiation between early-phase arrhythmogenic right ventricular cardiomyopathy (ARVC) and right ventricular outflow tract (RVOT)-ventricular tachycardia (VT) can be challenging, and correct diagnosis is important. We compared electrocardiogram (ECG) parameters and morphological right ventricular (RV) abnormalities and investigated if ECG and cardiac imaging can help to discriminate early-phase ARVC from RVOT-VT patients.

Methods and results

We included 44 consecutive RVOT-VT (47 ± 14 years) and 121 ARVC patients (42 ± 17 years). Of the ARVC patients, 77 had definite ARVC and 44 had early-phase ARVC disease. All underwent clinical examination, ECG, and Holter monitoring. Frequency of premature ventricular complexes (PVC) was expressed as percent per total beats/24 h (%PVC), and PVC configuration was recorded. By echocardiography, we assessed indexed RV basal diameter (RVD), indexed RVOT diameter, and RV and left ventricular (LV) function. RV mechanical dispersion (RVMD), reflecting RV contraction heterogeneity, was assessed by speckle-tracking strain echocardiography. RV ejection fraction (RVEF) was assessed by cardiac magnetic resonance imaging (CMR). Patients with early-phase ARVC had lower %PVC by Holter and PVC more frequently originated from the RV lateral free wall (both P < 0.001). RVD was larger (21 ± 3 vs. 19 ± 2 mm, P < 0.01), RVMD was more pronounced (22 ± 15 vs. 15 ± 13 ms, P = 0.03), and RVEF by CMR was decreased (41 ± 8 vs. 49 ± 4%, P < 0.001) in early-phase ARVC vs. RVOT-VT patients.

Conclusion

Patients with early-phase ARVC had structural abnormalities with lower RVEF, increased RVD, and pronounced RVMD in addition to lower %PVC by Holter compared with RVOT-VT patients. These parameters can help correct diagnosis in patients with unclear phenotypes.

Strain echocardiography is related to fibrosis and ventricular arrhythmias in hypertrophic cardiomyopathy

Aims

Hypertrophic 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 results

We 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.

Conclusion

GLS, 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.

Novel Imaging Approaches for Predicting Arrhythmic Risk

Determination of ventricular arrhythmic risk is crucial for guiding management of cardiac disease. Although for patients at increased risk an implantable cardioverter-defibrillator is recommended, it is widely acknowledged that current criteria for device use based predominantly on left ventricular ejection fraction are deficient. Genesis of ventricular arrhythmias involves a complex interaction of myocardial substrate abnormalities, precipitating triggers, and modulating factors. There are much data showing that by more directly assessing these factors, noninvasive imaging using echocardiography, radionuclide imaging, and cardiac magnetic resonance enhances arrhythmic risk stratification beyond ejection fraction and commonly used electrocardiographic and serum biomarkers. It is anticipated that further technological advancements studied in well-designed clinical trials will provide both more precise determination of risk and guide therapies to enhanced survival and patient well-being.

Right Ventricular Strain and Dyssynchrony Assessment in Arrhythmogenic Right Ventricular Cardiomyopathy: Cardiac Magnetic Resonance Feature-Tracking Study

BACKGROUND

Analysis of right ventricular (RV) regional dysfunction by cardiac magnetic resonance (CMR) imaging in arrhythmogenic RV cardiomyopathy (ARVC) may be inadequate because of the complex contraction pattern of the RV. Aim of this study was to determine the use of RV strain and dyssynchrony assessment in ARVC using feature-tracking CMR analysis.

METHODS AND RESULTS

Thirty-two consecutive patients with ARVC referred to CMR imaging were included. Thirty-two patients with idiopathic RV outflow tract arrhythmias and 32 control subjects, matched for age and sex to the ARVC group, were included for comparison purpose. CMR imaging was performed to assess biventricular function; feature-tracking analysis was applied to the cine CMR images to assess regional and global longitudinal, circumferential, and radial RV strains and RV dyssynchrony (defined as the SD of the time-to-peak strain of the RV segments). RV global longitudinal strain (-17±5% versus -26±6% versus -29±6%; P<0.001), global circumferential strain (-9±4% versus -12±4% versus -13±5%; P=0.001), and global radial strain (18 [12-26]% versus 22 [15-32]% versus 27 [20-39]%; P=0.015) were significantly lower and SD of the time-to-peak RV strain in all 3 directions were significantly higher among patients with ARVC compared with patients with RV outflow tract arrhythmias and controls. RV global longitudinal strain >-23.2%, SD of the time-to-peak RV longitudinal strain >113.1 ms, and SD of the time-to-peak RV circumferential strain >177.1 ms allowed correct identification of 88%, 75%, and 63% of ARVC patients with no or only minor CMR criteria for ARVC diagnosis.

CONCLUSIONS

Strain analysis by feature-tracking CMR helps to objectively quantify global and regional RV dysfunction and RV dyssynchrony in patients with ARVC and provides incremental value over conventional cine CMR imaging.

Arrhythmogenic right ventricular cardiomyopathy, clinical manifestations, and diagnosis

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.

Management of patients with Arrhythmogenic Right Ventricular Cardiomyopathy in the Nordic countries

OBJECTIVES

Diagnostics of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) are complex, and based on the 2010 Task Force document including different diagnostic modalities. However, recommendations for clinical management and follow-up of patients with ARVC and their relatives are sparse. This paper aims to give a practical overview of management strategies, risk stratification, and selection of appropriate therapies for patients with ARVC and their family members.

DESIGN

This paper summarizes follow-up and treatment strategies in ARVC patients in the Nordic countries. The author group represents cardiologists who are actively involved in the Nordic ARVC Registry which was established in 2009, and contains prospectively collected clinical data from more than 590 ARVC patients from Denmark, Norway, Sweden, and Finland.

RESULTS

Different approaches of management and follow-up are required in patients with definite ARVC and in genetic-mutation-positive family members. Furthermore, ARVC patients with and without implantable cardioverter defibrillators (ICDs) require different follow-up strategies.

CONCLUSION

Careful follow-up is required in patients with ARVC diagnosis to evaluate the need of anti-arrhythmic therapy and ICD implantation. Mutation-positive family members should be followed regularly for detection of early disease and risk stratification of ventricular arrhythmias.

New echocardiographic insights in short QT syndrome: More than a channelopathy?

BACKGROUND

Short QT syndrome (SQTS) is a congenital ion channel disease characterized by an increased risk of sudden cardiac death. Little is known about the possibility that accelerated repolarization alters mechanical function in SQTS.

OBJECTIVES

The study investigated the presence of left ventricular dysfunction and mechanical dispersion, assessed by tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE), and their correlation with QT interval duration and genetics.

METHODS

Fifteen SQTS patients (7 with HERG and 3 with KCNQ1 mutation) were studied. Electrocardiographic and echocardiographic parameters were compared with age- and sex-matched healthy controls.

RESULTS

When compared to the control group, SQTS patients showed reduced left ventricular contraction (global longitudinal strain: -16.0% ± 3.4% vs -22.6% ± 1.7%, P < .001; myocardial performance index 0.59 ± 0.17 vs 0.34 ± 0.08, P < .001) and a higher incidence of ejection fraction <55% (odds ratio 11, 95% confidence interval 1.045-374, P = .04). Mechanical dispersion assessed by TDI (P < .01) and STE (P < .001) was higher in the SQTS group than in controls; each parameter showed a significant inverse correlation with QT interval but not with QT dispersion.

CONCLUSION

This study showed that in SQTS systolic function may also be affected. SQTS patients presented a significant dispersion of myocardial contraction. TDI and STE could become part of the evaluation of this rare disease.

Global and regional left ventricular strain indices in post-myocardial infarction patients with ventricular arrhythmias and moderately abnormal ejection fraction

The aim of the study described here was to compare myocardial strains in ischemic heart patients with and without sustained ventricular tachycardia (VT) and moderately abnormal left ventricular ejection fraction (LVEF) to investigate which index could better predict VT on the basis of the analysis of global and regional left ventricular (LV) dysfunction. We studied 467 patients with previous myocardial infarction and LVEF >35%. Fifty-one patients had documented VT, and 416 patients presented with no VT. LV volumes and score index were obtained by 2-D echocardiography. Longitudinal, radial and circumferential strains were determined. Strains of the infarct, border and remote zones were also obtained. There were no differences in standard LV 2-D parameters between patients with and those without VT. Receiver operating characteristic values were -12.7% for global longitudinal strain (area under the curve [AUC] = 0.72), -4.8% for posterior-inferior wall circumferential strain (AUC = 0.80), 61 ms for LV mechanical dispersion (AUC = 0.84), -10.1% for longitudinal strain of the border zone (AUC = 0.86) and -9.2% for circumferential strain of the border zone (AUC = 0.89). In patients with previous myocardial infarction and moderately abnormal LVEF, peri-infarct circumferential strain was the strongest predictor of documented ventricular arrhythmias among all strain quantitative indices. Additionally, strain values from posterior-inferior wall infarctions had a higher association with arrhythmic events compared with global strain.

Left ventricular global longitudinal strain is associated with exercise capacity in failing hearts with preserved and reduced ejection fraction

Aims

Heart failure patients with reduced and preserved left ventricular (LV) ejection fraction (EF) show reduced exercise capacity. We explored the relationship between exercise capacity and systolic and diastolic myocardial function in heart failure patients.

Methods and results

Exercise capacity, by peak oxygen uptake (VO₂), was assessed in 100 patients (56 ± 12 years, NYHA functional class: 2.5 ± 0.9, EF: 42 ± 19%). LV systolic function, as EF and global longitudinal strain (GLS), and right ventricular function were assessed by echocardiography. Left atrial volume index and the ratio of peak early diastolic filling velocity (E) to early diastolic mitral annular velocity (e′) were measures of diastolic function. Thirty-seven patients had heart failure with preserved EF (HFpEF), defined as EF ≥50% and echocardiographic diastolic dysfunction. LV GLS and peak pulmonary arterial systolic pressure were independently correlated to peak VO₂ in the total study population and in HFpEF separately. LV GLS was superior to EF in identifying patients with impaired peak VO₂ <20 mL/kg/min as shown by receiver operating characteristic analyses [areas under curves 0.93 (0.89–0.98) vs. 0.85 (0.77–0.93), P < 0.05]. In patients with HFpEF, GLS was reduced below normal (−17.5 ± 3.2%) and correlated to E/e′ (R = 0.45, P = 0.005) and left atrial volume index (R = 0.48, P = 0.003), while EF did not.

Conclusion

GLS correlated independently to peak VO₂ in patients with reduced and preserved EF and was superior in identifying patients with reduced exercise capacity. In HFpEF, systolic function by GLS was impaired. There was a significant relationship between diastolic function and GLS, confirming a coupling between diastolic and longitudinal systolic function in HFpEF.

Vigorous physical activity impairs myocardial function in patients with arrhythmogenic right ventricular cardiomyopathy and in mutation positive family members

Aims

Exercise increases risk of ventricular arrhythmia in subjects with arrhythmogenic right ventricular cardiomyopathy (ARVC). We aimed to investigate the impact of exercise on myocardial function in ARVC subjects.

Methods and Results

We included 110 subjects (age 42 ± 17 years), 65 ARVC patients and 45 mutation-positive family members. Athletes were defined as subjects with ≥4 h vigorous exercise/week [≥1440 metabolic equivalents (METs × minutes/week)] during a minimum of 6 years. Athlete definition was fulfilled in 37/110 (34%) subjects. We assessed right ventricular (RV) and left ventricular (LV) myocardial function by echocardiography, and by magnetic resonance imaging (MRI). The RV function by RV fractional area change (FAC), RV global longitudinal strain (GLS) by echocardiography, and RV ejection fraction (EF) by MRI was reduced in athletes compared with non-athletes (FAC 34 ± 9% vs. 40 ± 11%, RVGLS –18.3 ± 6.1% vs. –22.0 ± 4.8%, RVEF 32 ± 8% vs. 43 ± 10%, all P < 0.01). LV function by LVEF and LVGLS was reduced in athletes compared with non-athletes (LVEF by echocardiography 50 ± 10% vs. 57 ± 5%, LVEF by MRI 46 ± 6% vs. 53 ± 8%, and LVGLS –16.7 ± 4.2% vs. –19.4 ± 2.9%, all P < 0.01). The METs × minutes/week correlated with reduced RV and LV function by echocardiography and MRI (all P < 0.01). The LVEF by MRI was also reduced in subgroups of athlete index patients (46 ± 7% vs. 54 ± 10%, P = 0.02) and in athlete family members (47 ± 3% vs. 52 ± 6%, P < 0.05).

Conclusion

Athletes showed reduced biventricular function compared with non-athletes in ARVC patients and in mutation-positive family members. The amount and intensity of exercise activity was associated with impaired LV and RV function. Exercise may aggravate and accelerate myocardial dysfunction in ARVC.

Carotid artery intima-media thickness is closely related to impaired left ventricular function in patients with coronary artery disease: a single-centre, blinded, non-randomized study

Background

Atherosclerosis is the underlying cause of the majority of myocardial infarctions and ischemic strokes. Carotid intima-media thickness (IMT) is a surrogate measure of atherosclerotic cardiovascular disease. Left ventricular (LV) function can be accurately assessed by 2D speckle-tracking strain echocardiography (2D-STE). The aim of this study was to assess the relationship between carotid IMT and LV dysfunction assessed by strain echocardiography in patients with coronary artery disease (CAD).

Methods

Thirty-one patients with symptoms of CAD were examined with coronary angiography, cardiac echocardiography and carotid ultrasound. Layer-specific longitudinal strains were assessed from endo-, mid- and epicardium by 2D-STE. LV global longitudinal strain (LVGLS) was averaged from 16 longitudinal LV segments in all 3 layers. LVGLS results were compared with coronary angiography findings in a receiver operating curve (ROC) to determine the cut-off for normal and pathological strain values. The calculated optimal strain value was compared to maximal carotid IMT measurements.

Results

The ROC analysis for strain versus coronary angiography was: area under curve (AUC) = 0.91 (95% CI 0.80 – 1.0), cut-off value for endocardial LVGLS: -16.7%. Further analyses showed that increased carotid IMT correlated with low absolute strain values (p = 0.006) also when adjusted for hypertension, smoking, hyperlipidemia, diabetes and BMI (p = 0.02).

Conclusions

In this study increased carotid IMT values were associated with decreased LV function assessed by strain measurements. These findings support the use of carotid IMT measurements to predict the risk of coronary heart disease.

Right ventricular cardiomyopathies: a multidisciplinary approach to diagnosis

The physiological importance of the right ventricle (RV) has been underestimated over the past years. Finally in the early 1950s through the 1970s, cardiac surgeons recognized the importance of RV function. Since then, the importance of RV function has been recognized in many acquired cardiac heart disease. RV can be mainly or together with left ventricle (LV) affected by inherited or acquired cardiomyopathy. In fact, RV morphological and functional remodeling occurs more common during cardiomyopathies than in ischemic cardiomyopathies and more closely parallels LV dysfunction. Moreover, there are some cardiomyopathy subtypes showing a predominant or exclusive involvement of the RV, and they are probably less known by cardiologists. The clinical approach to right ventricular cardiomyopathies is often challenging. Imaging is the first step to raise the suspicion and to guide the diagnostic process. In the differential diagnosis, cardiologists should consider athlete's heart, congenital heart diseases, multisystemic disorders, and inherited arrhythmias. However, a multiparametric and multidisciplinary approach, involving cardiologists, experts in imaging, geneticists, and pathologists with a specific expertise in these heart muscle disorders is required.

Arrhythmogenic ventricular cardiomyopathy: A paradigm shift from right to biventricular disease

Arrhythmogenic ventricular cardiomyopathy (AVC) is generally referred to as arrhythmogenic right ventricular (RV) cardiomyopathy/dysplasia and constitutes an inherited cardiomyopathy. Affected patients may succumb to sudden cardiac death (SCD), ventricular tachyarrhythmias (VTA) and heart failure. Genetic studies have identified causative mutations in genes encoding proteins of the intercalated disk that lead to reduced myocardial electro-mechanical stability. The term arrhythmogenic RV cardiomyopathy is somewhat misleading as biventricular involvement or isolated left ventricular (LV) involvement may be present and thus a broader term such as AVC should be preferred. The diagnosis is established on a point score basis according to the revised 2010 task force criteria utilizing imaging modalities, demonstrating fibrous replacement through biopsy, electrocardiographic abnormalities, ventricular arrhythmias and a positive family history including identification of genetic mutations. Although several risk factors for SCD such as previous cardiac arrest, syncope, documented VTA, severe RV/LV dysfunction and young age at manifestation have been identified, risk stratification still needs improvement, especially in asymptomatic family members. Particularly, the role of genetic testing and environmental factors has to be further elucidated. Therapeutic interventions include restriction from physical exercise, beta-blockers, sotalol, amiodarone, implantable cardioverter-defibrillators and catheter ablation. Life-long follow-up is warranted in symptomatic patients, but also asymptomatic carriers of pathogenic mutations.

Different prognostic value of functional right ventricular parameters in arrhythmogenic right ventricular cardiomyopathy/dysplasia

BACKGROUND

The value of standard 2-dimensional transthoracic echocardiographic parameters for risk stratification in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is controversial.

METHODS AND RESULTS

We investigated the impact of RV fractional area change (FAC) and tricuspid annulus plane systolic excursion (TAPSE) for the prediction of major adverse cardiovascular events (MACE) defined as the occurrence of cardiac death, heart transplantation, survived sudden cardiac death, ventricular fibrillation, sustained ventricular tachycardia, or arrhythmogenic syncope. Among 70 patients who fulfilled the 2010 ARVC/D Revised Task Force Criteria and underwent baseline transthoracic echocardiography, 37 (53%) patients experienced MACE during a median follow-up period of 5.3 (interquartile range, 1.8-9.8) years. Average values for FAC, TAPSE, and TAPSE indexed to body surface area (BSA) decreased over time (P=0.03 for FAC, P=0.03 for TAPSE, and P=0.01 for TAPSE/BSA, each versus baseline). In contrast, median RV end-diastolic area increased (P=0.001 versus baseline). Based on the results of Kaplan-Meier estimates, the time between baseline transthoracic echocardiography and experiencing MACE was significantly shorter for patients with FAC <23% (P<0.001), TAPSE <17 mm (P=0.02), or right atrial short axis/BSA ≥25 mm/m(2) (P=0.04) at baseline. A reduced FAC constituted the strongest predictor of MACE (hazard ratio, 1.08 per 1% decrease; 95% confidence interval, 1.04-1.12; P<0.001) on bivariable analysis.

CONCLUSIONS

This long-term observational study indicates that TAPSE and dilation of right-sided cardiac chambers are associated with an increased risk for MACE in patients with ARVC/D with advanced disease and a high risk for adverse events. However, FAC is the strongest echocardiographic predictor of adverse outcome in these patients. Our data advocate a role for transthoracic echocardiography in risk stratification in patients with ARVC/D, although our results may not be generalizable to lower-risk ARVC/D cohorts.

Risk prediction of ventricular arrhythmias and myocardial function in Lamin A/C mutation positive subjects

AIMS

Mutations in the Lamin A/C gene may cause atrioventricular block, supraventricular arrhythmias, ventricular arrhythmias (VA), and dilated cardiomyopathy. We aimed to explore the predictors and the mechanisms of VA in Lamin A/C mutation-positive subjects.

METHODS AND RESULTS

We included 41 Lamin A/C mutation-positive subjects. PR-interval and occurrence of VA were recorded. Left ventricular (LV) myocardial function was assessed as ejection fraction and speckle tracking longitudinal strain by echocardiography. Magnetic resonance imaging was performed to assess fibrosis in a selection of subjects. Ventricular arrhythmias were documented in 21 patients (51%). Prolonged PR-interval was the best predictor of VA (P < 0.001). Myocardial function by strain was reduced in the interventricular septum compared with the rest of the LV segments (-16.7% vs. -18.7%, P = 0.001) and correlated to PR-interval (R = 0.41, P = 0.03). Myocardial fibrosis was found exclusively in the interventricular septum and only in patients with VA (P = 0.007). PR-interval was longer in patients with septal fibrosis compared with those without (320 ± 66 vs. 177 ± 40 ms, P < 0.001).

CONCLUSION

Prolonged PR-interval was the best predictor of VA in Lamin A/C mutation-positive subjects. Electrical, mechanical, and structural cardiac properties were related in these subjects. Myocardial function was most reduced in the interventricular septum and correlated to prolonged PR-interval. Myocardial septal fibrosis was associated with prolonged PR-interval and VA. Localized fibrosis in the interventricular septum may be the mechanism behind reduced septal function, atrioventricular block and VA in Lamin A/C mutation-positive subjects.

Utility of strain echocardiography at rest and after stress testing in arrhythmogenic right ventricular dysplasia

The introduction of speckle tracking imaging (STI) allowed the quantification of the regional myocardial function in the right ventricular (RV) free wall using deformation parameters. We sought to evaluate the potential utility of STI at rest and after stress to predict arrhythmogenic RV dysplasia (ARVD). We studied 19 patients with ARVD (diagnosed according to the task force criteria) and 19 healthy age- and gender-matched subjects. Both 2-dimensional and 3-dimensional echocardiography were performed. The RV and left ventricular annular peak systolic velocities were measured using tissue Doppler imaging. The RV-left ventricular peak systolic longitudinal strain (LS) was obtained in the basal, mid, and apical segments in the apical 4-chamber view using STI. An exercise stress-echocardiographic test was undertaken using bicycle ergometry with the patient in the supine position for all patients, and the indexes were assessed at peak effort. The STI measurements were determined using offline analysis programs. The 3-dimensional RV ejection fraction and strain were significantly lower in patients with ARVD than in the controls. The RV strain values at rest did not change significantly during maximum physical effort in the patients with ARVD. The receiver operating characteristic curves suggested that the thresholds offering an adequate compromise between sensitivity and specificity for the detection of ARVD were 9.35 cm/s for the RV annular peak systolic velocity (area under the curve 0.81), 42% for 3-dimensional RV ejection fraction (area under the curve 0.85), -25% for mean global RV-LS (area under the curve 0.86), -18% for the lowest peak systolic RV-LS (area under the curve 0.88), and -1.2 for peak minus baseline global change of stress RV-LS (area under the curve 0.92). In conclusion, STI at rest and during stress might enable quantitative assessment of RV function and the detection of ARVD and have potential clinical value in the treatment of these patients.

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. Fifteen patients were treated with lamotrigine and ten with carbamazepine. No significant abnormality was found in the standard ECG or SAECG three to nine months after initiation of AED therapy. In one patient, a VLP was detected at baseline and subsequent MRI demonstrated significant right ventricular pathology; therefore, this patient was excluded from the rest of the study. This exclusion along with only newly diagnosed patients with a low total seizure count being included in the study may explain the lack of AED-induced electrocardiographic abnormalities in this patient cohort.

Early detection of regional functional abnormalities in asymptomatic ARVD/C gene carriers

BACKGROUND

The overt stage of arrhythmogenic right ventricular (RV) dysplasia/cardiomyopathy (ARVD/C) is preceded by a concealed stage with minor or no signs of disease. However, sudden death may occur in this early phase. Deformation imaging may contribute to early diagnosis. The aims of this study were to compare the diagnostic accuracy of the conventional (1994) versus the recently published (2010) new echocardiographic criteria for ARVD/C and to evaluate the additional value of echocardiographic tissue deformation imaging to detect subclinical RV functional abnormalities in asymptomatic carriers of pathogenic ARVD/C mutations.

METHODS

Fourteen asymptomatic first-degree relatives of ARVD/C probands (the ARVD/C-r group; mean age, 38.0 ± 13.2 years) with a pathogenic plakophilin-2 mutation and a group of age-matched controls (n = 56; mean age, 38.2 ± 12.7 years) were included at a 1:4 ratio. A complete echocardiographic evaluation (dimensions, global systolic parameters, and visual assessment and deformation imaging of the RV free wall including Doppler tissue imaging and two-dimensional strain echocardiography) was obtained. Peak systolic strain less negative than -18% and/or postsystolic shortening (postsystolic index > 15%) in any RV segment was considered abnormal.

RESULTS

RV dimensions in the ARVD/C-r group were similar to those in controls (RV outflow tract, 15.4 ± 2.9 vs 14.4 ± 1.9 mm/m(2), P = NS; RV inflow tract, 18.6 ± 2.6 vs 19.1 ± 2.6 mm/m(2), P = NS), and global systolic parameters were moderately reduced (tricuspid annular plane systolic excursion, 20.0 ± 3.2 vs 23.9 ± 2.8 mm, P = .001; RV fractional area change, 40.3 ± 8.4 vs 40.6 ± 7.1, P = NS). According to task force criteria, 57% of the ARVD/C-r group and 29% of controls were classified as abnormal when applying the 1994 criteria and 29% and 4% when applying the 2010 criteria, respectively. Doppler tissue imaging and two-dimensional strain deformation (and strain rate) values were reduced in the ARVD/C-r group in the basal and mid RV segments compared with controls (P < .001). In the ARVD/C-r group, peak systolic strain less negative than -18% was seen in six patients (43%), postsystolic strain in nine (64%), and either abnormality in 10 (71%), almost exclusively in the basal segment; these findings were observed in none of the controls.

CONCLUSIONS

The 2010 criteria for ARVD/C improve specificity, whereas sensitivity is significantly reduced in this asymptomatic population. In contrast, echocardiographic deformation imaging detects functional abnormalities in the subtricuspid region in 71% of asymptomatic carriers of a pathogenic plakophilin-2 mutation, while regional deformation was normal in all control subjects, indicating superiority of both sensitivity and specificity with these new modalities.

Risk assessment of ventricular arrhythmias in patients with nonischemic dilated cardiomyopathy by strain echocardiography

BACKGROUND

Indications for prophylactic implantable cardioverter-defibrillator implantation in patients with nonischemic dilated cardiomyopathy (DCM) are based on left ventricular (LV) ejection fraction (LVEF), although LVEF has limited ability to predict arrhythmias. It has recently been shown that strain echocardiography can predict ventricular arrhythmias in patients after myocardial infarction. The aim of this study was to evaluate whether strain echocardiography may help in the risk stratification of ventricular arrhythmias in patients with DCM.

METHODS

Ninety-four patients with nonischemic DCM were prospectively included. By speckle-tracking strain echocardiography, global longitudinal strain was calculated as the average of peak longitudinal strain from a 16-segment LV model. The time interval from electrocardiographic peak R to peak negative strain was assessed in each LV segment. Mechanical dispersion was defined as the standard deviation of time to peak negative strain from 16 LV segments.

RESULTS

After a median of 22 months of follow-up (range, 1-46 months), 12 patients (13%) had experienced arrhythmic events, defined as sustained ventricular tachycardia or cardiac arrest. LVEF and global longitudinal strain were reduced in patients with DCM with arrhythmic events compared with those without (28 ± 10% vs 38 ± 13%, P = .01, and -6.4 ± 3.3% vs -12.3 ± 5.2%, P < .001, respectively). Global longitudinal strain showed greater area under the curve than LVEF to identify arrhythmic events in receiver operating characteristic curve analyses (P = .05). Patients with arrhythmic events had increased mechanical dispersion (98 ± 43 vs 56 ± 18 ms, P < .001). Mechanical dispersion predicted arrhythmias independently of LVEF (hazard ratio, 1.28; 95% confidence interval, 1.11-1.49; P = .001).

CONCLUSIONS

Global longitudinal strain is a promising marker of arrhythmias. Mechanical dispersion predicted arrhythmic events in patients with DCM independently of LVEF. Strain echocardiography may help in the risk stratification of patients with DCM not fulfilling current implantable cardioverter-defibrillator indications.