Abstract 16852: A Simple Voltage/Mass Index Improves Diagnosis of Cardiac Amyloidosis in Patients With Unexplained Left Ventricular “Hypertrophy”: An Electrocardiographic and Echocardiographic Study of More Than 500 Patients
Introduction: Cardiac amyloidosis can mimic other diseases with increased left ventricular (LV) wall thickness, including hypertrophic cardiomyopathy (HCM) and hypertensive heart disease (HHD). Although low QRS voltage is considered the most useful electrocardiographic tool for differential diagnosis, its sensitivity is limited and its diagnostic accuracy has been tested mainly in primary (AL) amyloidosis.
Hypothesis: We assessed the diagnostic accuracy of low QRS voltage and of two other criteria based on ECG voltage/echocardiographic mass indexes in a large cohort of patients affected by cardiac amyloidosis of different etiologies, HCM or HHD.
Methods: We studied 529 patients: 233 with biopsy proven amyloidotic cardiomyopathy (AC) (151 with AL; 82 with transthyretin-related amyloidosis [63 mutant, 19 wild-type]), 207 with HCM, 89 with HHD. Three diagnostic criteria were compared: 1) low QRS voltage (QRS amplitude ≤0.5 mV in all limb leads); 2) peripheral QRS score (sum of QRS voltages in the limb leads) divided by LV mass (indexed to body surface area), here named V/M1; 3) Sokolow index (sum of S wave in lead V1 plus R wave in lead V5 or V6) divided by cross-sectional area of the LV wall (calculated according to the formula of Carroll JD, 1982), here named V/M2. ROC curves were constructed to identify the best cut off values for V/M1 and V/M2. In order to reproduce the most frequent clinical needs and scenarios, we tested all the criteria in the following groups: all the AC vs HCM+HHD; all the AC vs HCM; AL vs HCM+HHD; AL vs HCM.
Results: are reported in the Table.
Conclusions: In patients with increased LV wall thickness, AC can be accurately, non invasively, identified by combining ECG/echocardiographic findings. Peripheral QRS score/LV mass (V/M1) provides the best diagnostic performance (definitely superior to low QRS voltage alone), particularly when AC is not only related to AL etiology.
- © 2010 by American Heart Association, Inc.