Cardiac magnetic resonance imaging provides more than a diagnosis

We thank Dr Assadi et al. for their valuable comments on the utility of cardiac magnetic resonance imaging (CMR) in patients with ventricular tachycardia of idiopathic origin.¹ Dr Assadi et al. points out that CMR is helpful when conventional tests do not provide sufficiently clear data on ventricular function or localized cardiac pathologies.

Though pathologies may reflect geography and socio-economic factors, we share the views of Dr Assadi and colleagues that CMR is a very valuable tool in the work-up of patients suffering from tachyarrhythmias. In fact, the data presented by Dr Assadis group and ourselves² suggest that the patients across regions share similar aetiologies. In detail, in 11/26 (42%) patients presented in the work by Dr Assadi, CMR provided diagnostic findings such as a cardiomyopathy whereas non-diagnostic but abnormal findings were present in 8/26 (31%) patients. Similarly, in our cohort, structural heart disease was confirmed by CMR in 32/79 (41%) patients with ventricular tachycardia.

CMR can change the diagnosis in patients suffering from malignant arrhythmias.³ We showed that CMR was the major determinant for revision of an initial diagnosis in 38/79 (48%) patients but CMR provides even more. To secure an optimal work-up, before initiating screening of first-degree relatives, a correct diagnosis in the proband is crucial, and our results show that the indication for family screening was affected by CMR findings in 17/79 (22%) cases. Importantly, CMR identified arrhythmic substrates, which did not warrant screening of relatives, and in 1/10, a suspected cardiomyopathy was ruled out by CMR.

Thus, improved imaging by CMR is clinically very useful, also in patients considered to suffer from a primary arrhythmia, as a supplement to conventional work-up programmes. We suggest that a prospective multinational registry on cardiac arrest survivors would enhance our basic insight into these serious cases.

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