Arrhythmogenic right ventricular cardiomyopathy in Boxer dogs: the diagnosis as a link to the human disease.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a myocardial disease with an increased risk for ventricular arrhythmias. The condition, which occurs in Boxer dogs, shares phenotypic features with the human disease arrhythmogenic cardiomyopathy (ACM) suggesting its potential as a natural animal model. However, there are currently no universally accepted clinical criteria to diagnose ARVC in Boxer dogs. We aimed to identify diagnostic criteria for ARVC in Boxer dogs defining a more uniform and consistent phenotype. METHODS AND RESULTS: Clinical records from 264 Boxer dogs from a referral veterinary hospital were retrospectively analysed. ARVC was initially diagnosed according to the number of ventricular premature complexes (VPCs) in the 24-hour-Holter-ECG in the absence of another obvious cause. Dogs diagnosed this way had more VPCs, polymorphic VPCs, couplets, triplets, VTs and R-on-T-phenomenon and syncope, decreased right ventricular function and dilatation in comparison to a control group of all other Boxer dogs seen by the Cardiology Service over the same period. Presence of couplets and R-on-T-phenomenon on a 24h-ECG were identified as independent predictors of the diagnosis. A diagnosis based on ≥100 VPCs in 24 hours, presence of couplets and R-on-T phenomenon on a 24h-ECG was able to select Boxer dogs with a phenotype most similar to human ACM. CONCLUSION: We suggest the diagnosis of ARVC in Boxer dogs requires two out of the three following criteria: presence of ≥ 100 VPCs, presence of couplets or R-on-T-phenomenon on a 24 h-ECG. This results in a uniform phenotype similar to that described in human ACM and may result in the adoption of the term ACM for this analogous condition in Boxer dogs.

Left ventricular noncompaction.

PURPOSE OF REVIEW: Isolated left ventricular noncompaction (LVNC) is a myocardial disorder characterized by excessive and prominent trabeculations of the left ventricle, associated with progressive systolic failure, stroke and arrhythmia. Until quite recently, LVNC was thought to be extremely rare, but, with greater awareness of the disease and improvements in echocardiographic technology, there has been a dramatic increase in the frequency of diagnosis. Recent studies suggest that the frequency of LVNC is determined in part by the diagnostic criteria used. RECENT FINDINGS: Up to 50% of adult patients with LVNC have mutations in genes encoding proteins of the cardiac sarcomere, suggesting that LVNC might represent a new disease paradigm in which mutations that more typically cause dilated and hypertrophic cardiomyopathies result in abnormal ventricular morphogenesis. SUMMARY: In this review, we briefly summarize current clinical literature on LVNC, with a particular focus on the limitations of current diagnostic criteria and emerging data on the genetics of the disorder.

The binary endocardial appearance is a poor discriminator of Anderson-Fabry disease from familial hypertrophic cardiomyopathy.

OBJECTIVES: We compared the frequency of a binary endocardial appearance in patients with hypertrophic cardiomyopathy (HCM) and Anderson-Fabry disease (AFD). BACKGROUND: A recent study suggested that a binary endocardial appearance is a highly sensitive and specific discriminator of AFD from other causes of hypertrophic cardiomyopathy (HCM). METHODS: Fourteen patients with AFD (55.4 +/- 9.9 years, 9 men) and 14 patients with HCM (57.2 +/- 10.9 years, 9 men) were randomly selected from a dedicated patient database. Two-dimensional echo images were blindly reviewed by 2 experienced echocardiographers. RESULTS: Maximum left ventricular (LV) wall thickness, LV end-systolic dimension, fractional shortening, and left atrial size were similar in the 2 patient groups. The LV end-diastolic dimension was smaller in patients with HCM (p = 0.04). A binary sign was present in 8 of 28 patients (29%). The sensitivity and specificity of the binary sign as a discriminator of AFD from HCM were 35% and 79%, respectively. A binary sign was present in only 1 patient with LV wall thickness <15 mm. CONCLUSIONS: The binary endocardial appearance lacks sufficient sensitivity and specificity to be used as an echocardiographic screening tool.

Diagnosis of left-ventricular non-compaction in patients with left-ventricular systolic dysfunction: time for a reappraisal of diagnostic criteria?

AIMS: Left-ventricular non-compaction (LVNC) is characterized by excessive and prominent left-ventricular (LV) trabeculations and may be associated with systolic dysfunction in advanced disease. We sought to determine the proportion of patients fulfilling LVNC criteria in an adult population referred to a heart failure clinic using current diagnostic criteria. METHODS AND RESULTS: One hundred and ninety-nine patients [age 63.5 +/- 15.9 years, 124 (62.3%) males] with LV systolic impairment were studied. All underwent clinical examination, electrocardiography, and 2-D echocardiography. The number of patients fulfilling diagnostic criteria for LVNC was retrospectively determined using three published definitions. Results were compared with 60 prospectively evaluated normal controls (age 35.7 +/- 13.5 years; 31 males, 30 blacks). Forty-seven patients (23.6%) fulfilled one or more echocardiographic definitions for LVNC. Patients fulfilling LVNC criteria were younger (P = 0.002), had larger LV end-diastolic dimension (P < 0.001), and smaller left atrial size (P = 0.01). LVNC was more common in black individuals (35.5 vs. 16.2%, P = 0.003). Five controls (four blacks) fulfilled one or more LVNC criteria. CONCLUSIONS: This study demonstrates an unexpectedly high percentage of patients with heart failure fulfilling current echocardiographic criteria for LVNC. This might be explained by a hitherto underestimated cause of heart failure, but the comparison with controls suggests that current diagnostic criteria are too sensitive, particularly in black individuals.