Page 371 - fbkCardioDiabetes_2017

Cardio Diabetes Medicine 2017 347

Pitfalls in Computer ECG Interpretations

Dr.V.BALCHANDRAN
MD,MNAMS, FRCP, FACC, FCSI, FISC, Dip.Diab,

Chief Physician-Cardio-Diabetology,
Dr.Nairs Hospital, Kollam ,Kerala,

Introduction
Since the introduction of the string galvanometer by an accuracy of only 54% with a sensitivity of 72%,
Willem Einthoven more than a century ago, the ECG a specificity of 93%, and a positive predictive value
has become the most commonly performed cardio- of 59.3%. The clinical impact of the ECG-C misinter-
vascular test and an essential diagnostic tool in clini- pretation was evaluated by other investigators who
cal cardiology. The transition from analogue to digital demonstrated that 19% of ECG-C had the rhythm
ECGs resulted in automated computer analysis of the misinterpreted as atrial fibrillation (3). Failure of the
ECG (ECG-C) assuming a larger role in the diagnos- physician ordering the ECG to correct the inaccurate
tic interpretation. Yet, as the ECG-C has evolved into interpretation resulted in change in management and
a necessary tool of modern medical practice, many initiation of inappropriate treatment, including antiar-
physicians remain unaware of the hazards of relying rhytmic medications and anticoagulation, in 10% of
on these preliminary diagnostic interpretations. The patients. Additional unnecessary diagnostic testing

ECG-C clinical use should always be with the un- was performed based on the misinterpreted ECGs in
derstanding that they are preliminary interpretations 24% of patients. The ECG-C failed to identify many
and require reading and confirmation by qualified at-risk family members when used as a screening
electrocardiographer. With an increased reliance on tool for long QT syndrome (LQTS). The ECG-C erro-
these readings for point-of-care decision making, neously classified 6 of 23 family members known to
clinicians must remain mindful of many limitations have LQTS as normal
of the ECG-C. (1)
What is the reason that the most sophisticated com-
puter ECG interpreting software makes so many mis-
Pitfalls in interpretations. takes? The answer lies in the remarkable and exten-
Multiple prior investigations on the ECG-C interpre- sive capacity of the human brain to recognize visual
tation have demonstrated erroneous interpretation, patterns highly complex visual pattern recognition
resulting in unnecessary, potentially harmful medical system of our central nervous system. The skill in
treatment, and inappropriate use of medical resourc- pattern recognition would be a carefully preserved

es. A large international study compared the perfor- component of our brains that remains one of our
mance of 9 ECG-C programs with that of cardiologists species greatest assets. The computer that is read-
in interpreting ECGs in clinically validated cases of ing an ECG does not have pattern recognition skills
various cardiac disorders (2). The percentage of ECGs as yet, although this may well be developed in the
correctly classified by the ECG-C was lower than that future. Presently, computers read ECGs by making
for the cardiologists. More contemporary analysis of frequent determinations of the direction, positive or
the accuracy of ECG-C similarly concluded that there negative, that the ECG tracing is taking. By using this
are frequent errors in the interpretation of the cardiac information, the computer calculates whether a “q”
rhythm. In evaluating the ECG-C interpretation of the wave or ST-segment elevation or depression is pres-
cardiac rhythm, the ECG-C demonstrated an overall ent. This form of ECG interpretation is clearly not as
accuracy of 88.0%. Sinus rhythm was correctly inter- accurate as the process of pattern recognition built

preted in 95.0% of the ECGs with this rhythm. Howev- into the human central nervous system (4). Two ECGs
er, non sinus rhythms were correctly interpreted with

Cardio Diabetes Medicine