RT-31
|
New noninvasive
electrocardiographic markers of sudden death risk in hypertrophic cardiomyopathy
|
|
|
Mustafa A. Murda'h, Gang Yi,
Perry Elliott, William J. McKenna.
Department of Cardiological Sciences, St. George's Hospital
Medical School, London, UK
|
|
Introduction
|
|
Hypertrophic cardiomyopathy (HCM) is a primary
myo-cardial disease characterised by myocardial hypertrophy and myocyte disorganisation.
The majority of cases are caused by mutations in one of seven different genes encoding
cardiac sarcomeric proteins. The disease prevalence in the general population, based on 2D
echocardiographic diagnostic criteria, is estimated to be 1 in 500. Premature sudden
cardiac death (SCD) is a critical feature of the natural history. The determinants of
sudden death include myofibrillar disarray, myocardial fibrosis and myocardial ischaemia.
Identification of the arrhythmogenic substrate continues to be a goal in patient
characterisation. The annual mortality reported from tertiary referral centres is
approximately 2.5% in adults and 2-4% in adolescents and children1.
Several risk factors have been shown to identify patients at high risk of SCD: family
history of premature SCD (FHSCD), recurrent unexplained syncope (SYN), non-sustained
ventricular tachycardia (NSVT) on 48hr. Holter and a flat or hypotensive blood pressure
(FBP) response during upright exercise test. Although the negative predictive accuracy of
these factors is high, individually they have a low positive predictive accuracy.
Therefore, there is a need for further refinement of the risk stratification algorithm in
HCM.
QT dispersion and microvolt T wave alternans have been identified as noninvasive
markers for electrical instability and increased risk of SCD in several clinical
conditions (prolonged QT interval, ischemic heart disease). This manuscript discusses the
value of these non-invasive markers as potential predictors of SCD in patients with
hypertrophic cardiomyopathy2,3.
|
Key Words
|
|
Hypertrophic cardiomyopathy
sudden death, risk factor stratification, T wave alternans, QT interval dispersion, R
|
