Prognostic value of fragmented QRS in cardiac AL amyloidosis

Background: In light-chain (AL) cardiac amyloidosis, the 12-lead electrocardiogram (ECG) reflects myocardial amyloid infiltration with low limb voltages, pseudoinfarction patterns, and conduction abnormalities. Moreover, it is not unusual to see "aspecific" QRS complex abnormalities, such as notches and RsR' pattern in the absence of QRS prolongation, i.e. a fragmentation of QRS complexes (fQRS), that has been associated with myocardial scars and prognosis. Since cardiomyocyte damage and interstitial fibrosis are associated with cardiac amyloid deposition, aim of the present study was to analyze the prevalence and the potential prognostic value of fQRS in patients with cardiac amyloidosis.

Methods: We enrolled 375 consecutive untreated patients in whom a first AL amyloidosis diagnosis was concluded between 2008 and 2010, 264 with and 111 without heart involvement. Patients with a positive history of coronary disease were excluded from the analysis.

Results: The prevalence of fQRS was significantly higher in patients with cardiac AL amyloidosis (28.5% vs. 11.7%; p=0.0008). After a median follow-up of 561 days, Kaplan-Meier survival analysis revealed a significantly higher mortality in the fQRS group when compared with the "normal" QRS group (p=0.0008). No association was found between the presence of fQRS and the duration of PQ, QRS, and QTc intervals, the presence of peripheral low voltages or pseudonecrosis, NT-proBNP serum levels or cardiac wall thickness.

Conclusions: In patients with cardiac AL amyloidosis, the presence of fQRS at diagnosis has an independent prognostic value. Such a simple and cheap analysis in patients' diagnostic work-up may improve diagnosis and prognostic stratification.