Utility of tissue Doppler and strain echocardiography in arrhythmogenic right ventricular dysplasia/cardiomyopathy

Non-invasive investigations of the right heart: how and why?

The importance of right ventricular (RV) function in the clinical management of patients with cardiopulmonary disorders is now well recognized. However, due to both its shape and location and to the load dependence of its ejection fraction, accurate evaluation of its function is still a challenge. Echocardiography allows morphological, hemodynamic and functional assessment of the right heart. Displacement and deformation parameters derived from new techniques are promising tools. 3D echocardiography also has a potential interest in the quantification of RV volumes and ejection fraction. Radionuclide technique allows an easy and accurate measurement of right ventricular ejection fraction. MRI remains nowadays the technique of choice for the quantification of volumes and function of the RV. All these techniques have proven their interest in various diseases affecting the right heart. RV function is an important prognostic factor in heart failure and is a major component of functional capacity in such patients. In pulmonary arterial hypertension, echocardiography is the best tool for the routine follow-up of patients. Finally, all these non-invasive techniques of investigation of the right heart enable the diagnosis of specific right ventricular damage such as myocardial infarction or arrhythmogenic right ventricular dysplasia.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia: a not so rare "disease of the desmosome" with multiple clinical presentations

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a rare but increasingly recognized form of a cardiomyopathy, involving primarily the right ventricle. Mutations in seven candidate genes coding for five desmosomal proteins (plakoglobin, plakophilin-2, desmoplakin, desmoglein-2, desmocollin-2), for the cardiac ryanodine receptor-2, for the transforming growth factor beta-3, and for the transmembrane protein 43, respectively, are pathogenetically important. A typical feature of the disease is the replacement of the right ventricular myocardium by fibrofatty infiltrates, leading to electrical instability including ventricular arrhythmias in the early stages, and reduced contractility and heart failure later on. The left ventricle may also be involved. Unfortunately, the disease is often diagnosed post mortem only, especially in young adults dying suddenly during exercise. Since the disease is inherited in up to 50% of cases, the screening of relatives is important. The implantable cardioverter defibrillator is an important therapeutic tool. Nevertheless, the mortality of the disease remains to be 2%-4% per year. Several clinical, electrocardiographic, and imaging parameters were identified as risk predictors for an adverse outcome. In this paper, we describe distinct clinical presentations of ARVC/D, review the genetic background of the disease, and discuss its diagnosis and treatment.

Long-term follow-up in arrhythmogenic right ventricular cardiomyopathy using tissue Doppler imaging

AIM

To study patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and describe different echocardiographic parameters and their change over time during almost 10 years follow-up period.

METHODS

Fifteen patients (9 male, 6 female), aged 22-58 years (mean 40) with a diagnosis of ARVC, were followed up for a period of 6-10 years (mean 8.7). Twelve-lead and a signal- averaged ECG was recorded. Tricuspid and mitral annular motion and tissue Doppler imaging were registered by echocardiography. Wall motion score index (WMSI) was calculated for the left and right ventricles.

RESULTS

We registered significant reduction in systolic tissue velocity on right ventricle free wall between the first and last investigations: 7-17 cm/s (mean 11.8) to 4-15 (mean 9.1), p=0.005. WMSI increased by at least 0.2 in 10/14 patients for the right and in 8/15 patients for the left ventricle. A decrease in velocity time integral for the left ventricular outflow was observed (16-30 to 13-21, p=0.009).

CONCLUSION

ARVC is a progressive disease with individual variation. Left ventricular involvement may occur early in the disease. Tissue Doppler imaging is a useful tool to follow-up right ventricular abnormalities.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia: an update

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a genetic cardiomyopathy characterized by ventricular arrhythmias and structural abnormalities of the right ventricle (RV). The diagnosis is based on the International Task Force criteria. Cardiologists may not be aware of these diagnostic criteria for ARVC/D and may place too much importance on the results of MRI imaging of the right ventricle. Patients with ARVC/D usually have an abnormal 12-lead electrocardiogram, abnormal echocardiogram, and ventricular arrhythmias with a left bundle branch block morphology. If noninvasive testing suggests ARVC/D, invasive testing with an RV angiogram, RV biopsy, and electrophysiologic study is recommended. Once a diagnosis of ARVC/D is established, the main treatment decision involves whether to implant an implantable cardioverter-defibrillator. We also recommend treatment with beta blockers. Patients with ARVC/D are encouraged to avoid competitive athletics. Recent advances in the understanding of the genetic basis of ARVC/D have revealed that ARVC/D is a disease of desmosomal dysfunction.

The utility of magnetic resonance imaging in the evaluation of arrhythmogenic right ventricular cardiomyopathy

PURPOSE OF REVIEW

Perceptions of the utility of cardiovascular magnetic resonance in the evaluation of arrhythmogenic right ventricular cardiomyopathy have changed considerably in the past decade. This review offers an up-to-date perspective on the diagnostic role of cardiovascular magnetic resonance in the genetics era.

RECENT FINDINGS

Originally hailed as a putative gold standard in arrhythmogenic cardiomyopathy, cardiovascular magnetic resonance has received a more guarded reception lately owing to interobserver variability and lack of standardized protocols. Recent studies have nonetheless affirmed its value as an integral component of the diagnostic work-up. Quantitative volume analysis is relatively robust, but visualization of myocardial fat by spin-echo imaging is less reliable. Interpretation of wall motion abnormalities appears reproducible among expert readers. Emerging data suggest a key role for late gadolinium enhancement in detection of left ventricular involvement.

SUMMARY

Cardiovascular magnetic resonance in arrhythmogenic cardiomyopathy is facilitated by appropriate patient selection and preparation, experienced readers and operators, and a dedicated, comprehensive protocol. Indications for magnetic resonance assessment include proven arrhythmogenic cardiomyopathy in the family, unexplained ventricular arrhythmia, inverted T-waves in the right precordial or lateral leads, and/or family history of sudden cardiac death. Arrhythmia suppression is essential for optimal electrocardiographic triggering and image acquisition.