The early diagnosis of cardiac amyloidosis (CA) is paramount, since there are effective
therapies that improve patient survival. The diagnostic accuracy of classical electrocardiographic
(ECG) signs, such as low voltage, pseudoinfarct pattern, and conduction disturbances
in the diagnosis of CA, is inferior to that of the echocardiographic myocardial deformation
criteria; therefore, our aim was to find more accurate novel ECG criteria for this
purpose.We tested the diagnostic value of five novel ECG criteria, two of them devised
by us, in 34 patients with confirmed CA (20 transthyretin amyloidosis and 14 AL amyloidosis)
and 45 control patients with left ventricular hypertrophy on echocardiography due
to hypertension, valvular aortic stenosis and hypertrophic cardiomyopathy. The following
novel ECG criteria, that suggested CA, were tested: QRS amplitude in lead I < 0.55
mV (I < 0.55); QRS amplitude in lead aVR < 0.5 mV (aVR < 0.5); average QRS amplitude
of leads I + aVR < 0.575 mV [(I + aVR) < 0.575]; average QRS amplitude of leads I
+ aVR/average QRS amplitude of leads V1-4 < 0.375 [(I + aVR)/(V1-4 ) < 0.375]; average
QRS amplitude of leads I + aVR/longest intrinsicoid deflection in leads I,aVL,V1-6
< 0.0115 [(I + aVR)/I,aVL,V1-6 ID < 0.0115].The I < 0.55, aVR < 0.5, (I + aVR) < 0.575,
(I + aVR)/(V1-4 ) < 0.375, (I + aVR)/I,aVL,V1-6 ID < 0.0115 test accuracy (TA) were
81%, 84.8%, 82.3%, 84.8%, and 83.3%, respectively; the sensitivity (SE): 76.5%, 82.4%,
85.3%, 82.4%, and 76.9%; specificity (SP): 84.4%, 86.7%, 80%, 86.7%, and 87.5%; positive
predictive values (PPV): 78.8%, 82.4%, 76.3%, 82.4%, and 80%; negative predictive
values (NPV): 82.6%, 86.7%, 87.8%, 86.7%, and 85.4%; area under curve (AUC) values:
0.8922, 0.8794, 09016, 0.8824, and 0.8462 were respectively. These parameters of the
novel ECG criteria were at least as good as those reported by other authors in the
literature of the qualitative (TA: 67%, SE: 80%, SP: 34%, PPV: 75%, NPV: 42%, AUC:
0.57) and quantitative apical sparing (TA: 64-80%, SE: 66-81.3%, SP: 55-78.3%, PPV:
33-83.9%, NPV: 41-75%, AUC: 0.62-0.68) and left ventricular ejection fraction/global
longitudinal strain >4.1 (TA: 77%, SE: 93%, SP: 38%, PPV: 79%, NPV: 69%, AUC: 0.65)
echocardiographic criteria. Among the classical criteria, the low voltage in limb
leads criterion was present most frequently (in 73.5%) in patients with CA, with slightly
worse diagnostic value than the novel ECG criteria (TA: 78.5%, SE: 73.5%, SP: 82.2%,
PPV: 75.8%, NPV: 80.4%).The novel ECG criteria [mostly the aVR < 0.5, (I + aVR)/(V1-4
) < 0.375] seem at least as reliable in the diagnosis of CA as the best echocardiographic
myocardial deformation criteria and might be used either together with the echocardiographic
criteria or as stand-alone criteria to diagnose CA in the future.
