Bhavesh Sachdev

Prevalence of Anderson-Fabry Disease in Male Patients With Late Onset Hypertrophic Cardiomyopathy

Background—Although studies have suggested that “late-onset” hypertrophic cardiomyopathy (HCM) may be caused by sarcomeric protein gene mutations, the cause of HCM in the majority of patients is unknown. This study determined the prevalence of a potentially treatable cause of hypertrophy, Anderson-Fabry disease, in a HCM referral population. Methods and Results—Plasma &agr;-galactosidase A (&agr;-Gal) was measured in 79 men with HCM who were diagnosed at ≥40 years of age (52.9±7.7 years; range, 40–71 years) and in 74 men who were diagnosed at <40 years (25.9±9.2 years; range, 8–39 years). Five patients (6.3%) with late-onset disease and 1 patient (1.4%) diagnosed at <40 years had low &agr;-Gal activity. Of these 6 patients, 3 had angina, 4 were in New York Heart Association class 2, 5 had palpitations, and 2 had a history of syncope. Hypertrophy was concentric in 5 patients and asymmetric in 1 patient. One patient had left ventricular outflow tract obstruction. All patients with low &agr;-Gal activity had &agr;-Gal gene mutations. Conclusion—Anderson-Fabry disease should be considered in all cases of unexplained hypertrophy. Its recognition is important given the advent of specific replacement enzyme therapy.

Prospective evaluation of relatives for familial arrhythmogenic right ventricular cardiomyopathy/dysplasia reveals a need to broaden diagnostic criteria.

OBJECTIVES We sought to ascertain the prevalence and mode of expression of familial disease in a consecutive series of patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). BACKGROUND Autosomal-dominant inheritance is recognized in ARVC. The prevalence and mode of expression of familial disease in consecutive, unselected families is uncertain. METHODS First- and second-degree relatives of 67 ARVC index patients underwent cardiac evaluation with history and examination, 12-lead and signal-averaged electrocardiogram (ECG), two-dimensional and Doppler echocardiography, metabolic exercise testing and Holter monitoring. Diagnoses were made in accordance with published criteria. RESULTS Of 298 relatives, 29 (10%; mean age 37.4 +/- 16.4 years) had ARVC. These were from 19 of the 67 families, representing familial involvement in 28%. Of these affected relatives, 72% were asymptomatic, 17% had ventricular tachycardia (sustained VT 10%, nonsustained VT 7%) and 21% had left ventricular involvement. A further 32 relatives (11%; 37.7 +/- 12.4 years) exhibited nondiagnostic ECG, echocardiographic or Holter abnormalities. Fifteen of these relatives were from families with only the proband affected, and inclusion of this subset of relatives would have resulted in familial ARVC in 48% of index cases. Four additional relatives (1% to 3%) fulfilled diagnostic criteria for dilated cardiomyopathy without any features of right ventricular disease. CONCLUSIONS By using current diagnostic criteria, familial disease was present in 28% of index patients. A further 11% of their relatives had minor cardiac abnormalities, which, in the context of a disease whose mode of inheritance is autosomal dominant, are likely to represent early or mild disease expression. We advocate that the current ARVC diagnostic criteria are modified to reflect the broader spectrum of disease that is observed in family members.

Coronary microvascular dysfunction in male patients with Anderson-Fabry disease and the effect of treatment with α galactosidase A

Objective: To measure coronary flow reserve (CFR), an index of microvascular function, in Anderson-Fabry disease (AFD) at baseline and after enzyme replacement therapy (ERT). Methods and results: Mean (SD) myocardial blood flow (MBF) at rest and during hyperaemia (adenosine 140 μg/kg/min) was measured in 10 male, non-smoking patients (53.8 (10.9) years, cholesterol 5.5 (1.3) mmol/l) and in 24 age matched male, non-smoking controls (52.0 (7.6) years, cholesterol 4.5 (0.6) mmol/l) by positron emission tomography (PET). Resting and hyperaemic MBF and CFR (hyperaemic/resting MBF) were reduced in patients compared with controls (0.99 (0.17) v 1.17 (0.25) ml/g/min, p < 0.05; 1.37 (0.32) v 3.44 (0.78) ml/g/min, p < 0.0001; and 1.41 (0.39) v 3.03 (0.85), p < 0.0001, respectively). This coronary microvascular dysfunction was independent of cholesterol concentrations. PET was repeated in five patients after 10.1 (2.3) months of ERT; resting and hyperaemic MBF and CFR were unchanged after ERT (0.99 (0.16) v 0.99 (0.16) ml/g/min; 1.56 (0.29) v 1.71 (0.3) ml/g/min; and 1.6 (0.37) v 1.74 (0.28), respectively; all not significant). Conclusions: The results of the present study show that patients with AFD have very abnormal coronary microvascular function. These preliminary data suggest that ERT has no effect on coronary microvascular dysfunction. Further work is necessary to determine whether treatment at an earlier stage in the course of the disease may improve coronary microvascular function in patients with AFD.

Prevalence and clinical significance of systolic impairment in hypertrophic cardiomyopathy

Objectives: To determine the frequency of systolic impairment (SI) and its impact on the natural history of hypertrophic cardiomyopathy (HCM). Methods: 1080 patients (mean (SD) age 43 (15) years, 660 men) with HCM were evaluated. Initial assessment included history, examination, 48 hour Holter monitoring, cardiopulmonary exercise testing, and echocardiography; SI was defined as a fractional shortening (FS) ⩽ 25%. Survival data were collected at clinic visits or by direct communication with patients and their general practitioners. The results of serial echocardiography in 462 patients with normal FS at presentation are also reported. Results: 26 (2.4%) patients (49 (14) years, 18 men) had SI at the initial visit. During follow up (58 (49) months), nine (34.6%) died or underwent cardiac transplantation compared with 108 (10.2%) patients with normal FS (p  =  0.01). Five year survival from death (any cause) or transplantation was 90.1% (95% confidence interval (CI) 87.8 to 92.4) in patients with normal systolic function versus 52.4% (95% CI 25.2 to 79.6, p < 0.0001) in patients with SI. In patients who underwent serial echocardiography, 22 (4.8%, aged 41 (15) years) developed SI over 66 (40) months; the annual incidence of SI was 0.87% (95% CI 0.54 to 1.31). On initial evaluation patients who developed SI had a higher frequency of syncope (67 (15.2%) v 10 (45.5%) of those who did not develop SI, p  =  0.001), non-sustained ventricular tachycardia (91 (20.6%) v 11 (50%), p  =  0.002), and an abnormal blood pressure response on exercise (131 (29.7%) v 15 (68.2%), p  =  0.001). Patients with SI had greater wall thinning (p  =  0.001), left ventricular cavity enlargement (p < 0.0005), and deterioration in New York Heart Association functional class (p  =  0.001) during follow up. Thirteen (59.1%) patients who progressed to SI died or underwent transplantation compared with 38 (8.6%) patients who maintained normal systolic function. Conclusions: SI is an infrequent complication of HCM but, when present, is associated with a poor prognosis.

Pregnancy related complications in women with hypertrophic cardiomyopathy

Objectives: To determine whether pregnancy is well tolerated in hypertrophic cardiomyopathy. Setting: Referral clinic. Design: The study cohort comprised 127 consecutively referred women with hypertrophic cardiomyopathy. Forty (31.5%) underwent clinical evaluation before pregnancy. The remaining 87 (68.5%) were referred after their first pregnancy. All underwent history, examination, electrocardiography, and echocardiography. Pregnancy related symptoms and complications were determined by questionnaire and review of medical and obstetric records where available. Results: There were 271 pregnancies in total. Thirty six (28.3%) women reported cardiac symptoms in pregnancy. Over 90% of these women had been symptomatic before pregnancy. Symptoms deteriorated during pregnancy in fewer than 10%. Of the 36 women with symptoms during pregnancy, 30 had further pregnancies. Symptoms reoccurred in 18 (60%); symptomatic deterioration was not reported. Heart failure occurred postnatally in two women (1.6%). No complications were reported in 19 (15%) women who underwent general anaesthesia and in 22 (17.4%) women who received epidural anaesthesia, three of whom had a significant left ventricular outflow tract gradient at diagnosis after pregnancy. Three unexplained intrauterine deaths occurred in women taking cardiac medication throughout pregnancy. No echocardiographic or clinical feature was a useful indicator of pregnancy related complications. Conclusions: Most women with hypertrophic cardiomyopathy tolerate pregnancy well. However, rare complications can occur and therefore planned delivery and fetal monitoring are still required for some patients.

Isolated cardiac manifestations in Fabry disease: the UK experience

Cardiac abnormalities are common in patients with Fabry disease, and may be the only clinical manifestation of the disease in some patients. At St Georges Hospital Medical School, a national referral centre for hypertrophic cardiomyopathy in the UK, a study of 153 consecutively referred male patients revealed that 4% had Fabry disease. This increased to 6% in patients over 40 years of age. All these patients had electrocardiographic (ECG) abnormalities, most of which were consistent with those found in patients with classic Fabry disease: left ventricular hypertrophy, repolarization abnormalities and a prolonged QRS complex. A study of heterozygote females with Fabry disease also showed ECG and echocardiographic abnormalities in most patients.

The prevention of sudden death in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a familial myocardial disease caused by mutations in cardiac sarcomeric proteins. HCM is characterised by myocyte disarray and myocardial fibrosis. Most patients are largely asymptomatic but some are prone to a number of disease-related complications, the most problematic of which is sudden cardiac death. Diagnosing patients who are at risk has not been easy because of the clinical heterogeneity of the disease, the frequent absence of symptoms prior to sudden cardiac death and the relatively low disease prevalence and annual mortality rates. To date, both low-dose amiodarone and internal cardioverter/defibrillator inplantation have been advocated in high-risk individuals. Further improvements in clinical understanding and risk stratification are necessary to identify HCM patients who are at high risk of sudden death.