Reported by Mid-day
A normal ECG may look reassuring, but it does not always mean the heart is safe. According to senior consultant cardiologist Dr Siddharth V Dagli, "up to 10 per cent of patients experiencing an active heart attack will have a completely normal ECG." He explains, "The heart is divided into regions - front, sides, and back. The ECG is excellent at detecting damage to the front and sides of the heart, but it's remarkably blind to damage at the back and right side.
In the very earliest phase of a heart attack, sometimes the first few minutes to hours, the ECG looks completely normal. A patient arriving at the emergency room during this window has a normal ECG despite active, ongoing heart muscle death."
Dr Dagli says this is why a single ECG should not be treated as enough to rule out a heart attack. Troponin I, a blood test that detects damage to heart muscle, is another crucial part of the diagnosis. However, even that test can be normal during the first few hours.
The proper way to diagnose a heart attack is through serial testing," he says, "An immediate troponin test, a repeat ECG after 15 minutes and another troponin measurement after three hours."
He also flags women, younger patients, diabetics, and people with previous heart attacks as groups in whom diagnosis can be more easily missed. "A normal ECG that sends a patient home is not reassuring; it's dangerous," he says.
