Left ventricular dysfunction in sickle cell disease: the value of an electrocardiographic marker of increased risk of arrhythmia

Editorial left ventricular dysfunction in sickle cell disease: the value of an electrocardiographic marker of increased risk of arrhythmia Sickle cell disease is one of the most prevalent genetic diseases worldwide; affecting 1/400 individuals of African descent as well as people of Arab, Indian and Hispanic descents. Abnormalities of cardiovascular function have increasingly been documented in sickle cell disease patients. Reports from several clinical studies in recent times have drawn attention to some 'emerging' cardiac pathologies in sickle cell disease and their potentially negative impact on cardiovascular function in these patients. Among these include myocardial infarction without coronary artery disease, pulmonary hypertension and cor pulmonale. 4-7 Moreover, sudden unexpected death has become increasingly recognised as an important clinical feature of both the homozygous and heterozy-gous sickling syndromes; although the exact nature and its cause has remained unexplained. The emergence of cardiac complications in sickle cell disease patients could be attributed to the increasing life expectancy observed in these patients. Recent data indicates that 86 to 90% of patients survive to beyond 20 years of age. 11 With the continued development of improved management and supportive care for patients with sickle cell anaemia and the resultant increase in life span, the spectrum of cardiac dysfunction is likely to enlarge in the future. The mechanism underlying cardiac dysfunction in sickle cell anaemia has been extensively studied and multiple mechanisms have been proposed. In addition to the impaired microvascular circulation from intravascular plugs of sickled erythrocytes, other contributory factors include: extensive fibromuscular dysplastic narrowing of small cardiac arteries, non-inflammatory focal degeneration and apoptosis, platelet abnormalities or similar stimuli for endothelial and smooth muscle proliferation. The hyperkinetic circulation as a result of chronic anaemia contributes to eccentric ventricular hypertrophy and cardio-megaly, and the severity of cardiac chamber dilatation progresses with increasing anaemia. Despite myocardial remodelling/ hypertrophy, the patients have increased myocardial wall stress as well as impaired ventricular relaxation. 16 Data from clinical studies evaluating left ventricular systolic function using load-independent measures of myocardial contrac-tility have revealed significant systolic dysfunction in sickle cell anaemia patients. The development of left ventricular systolic and/or diastolic dysfunction in sickle cell anaemia is associated with increased morbidity and mortality. 19 There is a large body of evidence showing that diastolic dysfunction in sickle cell disease contributes to pulmonary hypertension and represents an independent predictor of mortality in these patients. 19 It has been recognised that ischaemic phenomena associated …