Mr Joseph Selvanayagam,
I had the great pleasure of co-chairing this session on the value of imaging in the assessment of sudden death risk in the setting of cardiomyopathy. This proved to be a very stimulating and active session with the various speakers addressing the value of cardiovascular magnetic resonance, echocardiography and nuclear imaging to this topic.
The first speaker addressed the great strides made in late enhancement imaging in the assessment of scar in the setting of ischaemic cardiomyopathy and fibrosis assessment in the setting of various non ischaemic cardiomyopathies. Late Gadolinium (LG) imaging, which is simple and easy to use, has proven valuable for diagnosis and potentially prognosis in ischaemic and non ischaemic cardiomyopathy. Comment was made on the value of this technique in hypertrophic cardiomyopathy (HCM) with recent research highlighting the value of LG positivity in predicting the occurrence of non-sustained ventricular arrhythmia. However, it is too early to say whether Late Gadolinium is an independent marker of sudden death in HCM patients over and above traditional risk factors. It most probably has an adjunctive, rather than independent, role in risk stratification in HCM. The second speaker addressed the value of nuclear imaging in cardiomyopathy risk assessment. He particularly highlighted the value of MIBG imaging to enhance restratification in the setting of heart failure. MIBGs’ mechanism of action involves the sympathetic innovation of the heart; the degree of uptake of the agent has been found in the recent ADMIRE – HF (AdreView myocardial imaging for risk evaluation in heart failure) trial to predict adverse cardiac events such as arrhythmia or sudden cardiac death. Whilst preliminary, this imaging option may help clarify clinical decision making in the setting of heart failure by potentially segmenting patients who would benefit most from an implantable defibrillator from those who should be treated with other measures. However, as was pointed out during the session, the incremental value of this over and above traditional clinical and functional parameters for risk prediction is still unclear. The third speaker spoke about the role of echocardiography for risk stratification.It was highlighted that echo forms the basis of baseline testing in virtually all patients, and affords a diagnosis into broad categories of hypertrophic or dilated cardiomyopathy. In addition, in the case of hypertrophic cardiomyopathy, it is often able to highlight recognised risk factors such as left ventricular flow tract gradient or extreme left ventricular hypertrophy. On the other hand, in the case of dilated cardiomyopathy, it is often unable to further stratify patients into the specific aetiologies such as idiopathic dilated cardiomyopathy of an idiopathic type or that arising from myocarditis. The fourth speaker commented on the difficult area of diagnosis and prognosis of arrhythmogenic right ventricular cardiomyopathy (ARVC).It was highlighted that this condition has a feature of isproportionate “arrhythmogenicity“ (arrhythmic risk out of proportion to ventricular function) and hence no single imaging or clinical parameter is able to predict high risk for sudden death with any degree of certainty. The speaker highlighted the value of composite clinical and imaging tools for risk prediction. It was recognised that early ARVC phenotype recognition can be subtle on CMR imaging and requires expert readers.
In conclusion, the impression I have from these excellent talks is that imaging will continue to play a key role in mechanistic assessment of sudden death in various cardiomyopathies and may also potentially add incremental value to already existing risk stratifying tools. Especially in the areas of cardiovascular magnetic resonance and nuclear imaging, more light will be shed from prospective large scale studies that are currently underway.
Arrhythmias management and sudden death. The value of imaging
This congress report accompanies a presentation given at the ESC Congress 2009. Written by the author himself/herself, this report does not necessarily reflect the opinion of the European Society of Cardiology.
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