212 | Chapter 10 While PVCs from the basal LV correspond with the anatomical location of MAD, this relation is less clear for PVCs from the RVOT. The latter were previously reported in MAD, but mainly with concurrent LVOT PVCs.9 Ventricular ectopy from areas in close proximity to the mitral annular region and papillary muscles has been attributed to mechanical traction in a subgroup of IVF patients with bi-leaflet MVP9 and the same mechanism of traction induced ectopy may be present in MAD.36 Bi-leaflet MVP was present in three female IVF patients in our cohort, in consistence with the previous description of the ‘malignant bi-leaflet MVP syndrome’, which was characterized by bi-leaflet MVP, frequent ventricular ectopy and female sex.9 Clinical implications A previous report demonstrated a case of unexplained cardiac arrest in an otherwise healthy patient, whereby clear MAD was found upon secondary evaluation of cardiac imaging data.37 We confirm that in 11% of our IVF cohort, MAD and/or MVP can be observed during focused analysis of CMR images, while it was previously left unrecognized in a thorough diagnostic process. In a matched cohort of healthy controls, MAD and MVP were rarely found. Overt MVP in combination with extensive myocardial fibrosis in the annular region and papillary muscles was not observed in our IVF cohort. These subjects were most likely already diagnosed with an arrhythmic mitral valve prolapse according to current clinical standards and did not end up in the IVF cohort.9,38 Our findings suggest that mitral valve disease may still contribute as pro-arrhythmic factor in a subset of IVF patients. However, one could still argue that minor degrees of MAD are a bystander in IVF. A future, larger prospective study is needed to further evaluate our findings. We advocate that evaluation of the mitral valve region deserves extra attention in the extensive screening of patients with unexplained sudden cardiac arrest. The direct therapeutic consequences for IVF patients may be limited as they generally have a clear indication for secondary prevention ICD implantation. However, knowledge about the correlation between MAD and arrhythmias may yield prognostic value for IVF patients and might especially be important to identify a possible arrhythmogenic risk in family members. Limitations Although this is one of the largest IVF cohorts worldwide, the number of patients included is relatively small due to the rarity of the disease. Due to the retrospective nature of this study, image plane acquisition was already performed. Therefore, MAD measurements were confined to available CMR views. In addition, LGE imaging was not standardly performed in the older CMRs and in some cases could not be interpreted due to artefacts. Other studies suggest that MAD is also easily detectable on echocardiography, but the quality and focus of the images acquired are of great importance.8,35 We did not use echocardiography because we concluded that measurement of MAD distance on retrospective exams without focused images was not feasible. Holter monitoring was not routinely performed due to the retrospective set-up of the study. In addition, the number of patients with MAD or MVP was relatively small, hampering strong conclusions on clinical follow-up data. Larger prospective follow-up studies are needed to determine the potential impact of MAD/MVP on the prognosis of IVF patients.
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