I

Fig. 16.8 • Right ventricular (RV) angiogram (30° RAO view) demonstrating a localized RV outflow tract aneurysm as well as inferobasal (subtricuspid) akinesia with mild tricuspid regurgitation in a patient with ARVC/D (arrows)

specificity of 96% for the correct diagnosis of ARVC/D [16] (Table 16.1).

No correlation was demonstrated between histology and specific wall motion abnormalities. In particular, aneurysms were associated with fibrous as well as adipose tissue. However, histological findings may be useful in confirming the diagnosis and assessing the activity of the cardiomyopathic process. In a stable phase of ARVC/D, fibrofatty replacement is the predominant finding, whereas in phases of active disease and progression, histological signs of (sub)acute necrosis, apoptosis, and inflammation, as well as electrical instability may be present [21].

Table 16.1 • Diagnostic accuracy of RV angiography in ARVC/D. Adapted from [16]

ARVC/D (n=32)

DCM (n=27)

ASD (n=28)

Control (n=18)

p-value

EDV-RV (ml/m2)

131

165

141

95

NS

ESV-RV (ml/m2)

62

104

66

38

NS

EF-RV (%)

53

38

54

60

NS

RVOT-diameter (cm)

5

6

5

2

NS

Long axis RV (cm)

12

14

12

5

NS

Dyskinesia RV-apex (%)

41

7

0

0

<0.0001

Dyskinesia RV-inferior (%)

28

7

0

0

<0.0001

Bulging RVOT (%)

75

11

18

11

<0.0001

Bulging inferobasal (%)

91

56

14

5

<0.0001

Tricuspid prolapse (%)

41

7

22

0

<0.001

ARVC/D, arrhythmogenic right ventricular cardiomyopathy/dysplasia; ASD, atrial septal defect; DCM,dilated cardiomyopathy; £DV,end diastolic volume; ££,ejection fraction; £SV,end systolic volume; RV,right ventricle; RVOT,right ventricular outflow tract

ARVC/D, arrhythmogenic right ventricular cardiomyopathy/dysplasia; ASD, atrial septal defect; DCM,dilated cardiomyopathy; £DV,end diastolic volume; ££,ejection fraction; £SV,end systolic volume; RV,right ventricle; RVOT,right ventricular outflow tract

Tricuspid Regurgitation

In ARVC/D, tricuspid regurgitation results from two mechanisms: a dilated tricuspid annulus secondary to RV enlargement, and fibrotic involvement of tricuspid papillary muscles. Therefore, clinically relevant tricuspid regurgitation mainly occurs in patients with advanced stages of ARVC/D (Fig. 16.9).

Left Ventricular Involvement

LV involvement of ARVC/D has been reported to be more frequently present than clinically diagnosed [3,10]. The main findings are localized abnormalities of wall motion (hypokinesia, localized dyskinesia) in the anterior, basal, and apical walls (Fig. 16.10). However, global LV function is rarely affected.

A review of LV cine angiograms performed by the group in Padua [22] showed unusual aspects of parietal motion in at least 60% of cases. LV end diastolic volumes (90±29 ml/m2) and ejection fractions (60±6%) as well as stress/end systolic volume ratios (5.4±2) and mass/volume ratios (0.8±0.1) were normal in a group of patients with ARVC/D less than 20 years old. In an older group (age 38±13 years), only the end diastolic volume was slightly increased (93±36 ml/m2). Statistical analysis showed overlapping of the functional indices in the young and adult groups [22]. However, an increase of dyskinetic areas was observed in the adult group. During a follow-up period of 11.5 years

Fig. 16.9 • Right ventricular (RV) angiogram (30° RAO view, systole) showing global RV enlargement and severe dysfunction in ARVC/D. There is pronounced dilatation of the RV outflow tract, akinesia of the inferior and subtricuspid walls and functional tricuspid regurgitation (grade 2) due to annulus dilatation

Fig. 16.10 • Left ventricular (LV) angiogram (30° RAO view, end systole) showing LV involvement with anteroapical akinesia (arrows) in a patient with a long history of progressive ARVC/D and severe global right ventricular enlargement and dysfunction

(range 4 to 17 years), RV and LV angiography was repeated in four patients and demonstrated deterioration of RV or LV function in two patients each.

These findings are consistent with the experience in Münster, where LV involvement of ARVC/D was mainly detected in patients with a long history of, and advanced stages of, RV dysfunction.

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