Noninvasive diagnosis of biopsy-proven cardiac amyloidosis.
OBJECTIVE
This study analyzed the utility of electrocardiographic (ECG) and echocardiographic findings in the diagnosis of amyloidosis proven by endomyocardial biopsy.


BACKGROUND
Cardiac amyloidosis is associated with characteristic ECG and echocardiographic changes, yet each finding alone is relatively nonspecific. A combination of noninvasive prognostic parameters would be desirable for this tissue-based diagnosis.


METHODS
We performed an analysis of 196 consecutive patients referred for endomyocardial biopsy because of clinical suspicion of cardiac amyloidosis. The diagnosis was confirmed in 58 patients (29%). The ECGs, echocardiograms, and right heart hemodynamic data were reviewed to determine which findings strongly correlate with the diagnosis. These findings were then used to build multivariate logistic regression models that predict the log-odds of having cardiac amyloidosis.


RESULTS
The univariate analysis showed that low-voltage and pseudo-infarction patterns on the ECG and increased myocardial thickness and speckled-appearing myocardium on the echocardiogram were associated with biopsy-proven cardiac amyloidosis (each p < 0.01). In multivariate logistic regression models, a combination of a low voltage and measures of myocardial thickness produced the most statistically useful models. For instance, one model showed that if a low voltage was present and interventricular septal thickness is >1.98 cm, the diagnosis of cardiac amyloidosis could be made with a sensitivity of 72% and a specificity of 91%. In this model, the positive predictive and negative predictive values were 79% and 88%, respectively.


CONCLUSIONS
In patients with suspected cardiac amyloidosis, a combination of noninvasive parameters-namely, a low voltage and increased intraventricular septal thickness-is a useful diagnostic tool.
Rahman
Joseph E
JE
Division of Cardiology, Department of Medicine, Johns Hopkins Bayview Medical Center, 4940 Eastern Avenue, Baltimore, MD 21224-2780, USA.
Helou
Emelie F
EF
Gelzer-Bell
Ramona
R
Thompson
Richard E
RE
Kuo
Chih
C
Rodriguez
E Rene
ER
Hare
Joshua M
JM
Baughman
Kenneth L
KL
Kasper
Edward K
EK
D000686:Amyloidosis / Q000150:complications / Q000175:diagnosis* / Q000473:pathology; D001706:Biopsy; D009202:Cardiomyopathies / Q000150:complications / Q000175:diagnosis* / Q000473:pathology; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D012189:Retrospective Studies