Health Matters…Your cardiologist ordered what test?

by Dr. Max Hammonds

From the first classes in Physical Diagnosis, young medical students learn to listen to the heart by auscultation – that is, by listening to the heart with a stethoscope. Invented by Rene Laennec in 1816, the stethoscope allowed physicians – from that time on – to hear with clarity the sounds of the heart as it beats. These same medical students memorize the various normal sounds coming from the beating heart. They also learn to recognize a number of abnormal sounds from the heart, each correlated with a particular malfunction of the valves or the strength of the walls or the timing of the heart.

But this method of diagnosis is limited by the size of the patient, the skill of the physician, and the lack of certainty that all abnormal sounds necessarily indicate a diseased heart. By not being able to directly “see” the heart in action, auscultation remains somewhat limited in determining the health of the heart.

Today other modes of “seeing” the heart are available to the medical practitioner. When the primary care provider hears certain abnormal sounds, he/she can do further non-invasive testing, that is, not requiring physical invasion of the body.

The first test that a clinician might ask for is an electrocardiogram (ECG or EKG) which graphically displays the electrical activity of the heart over time. This graphic tracing specifically enables the clinician to “see” the timing of the heart function, especially specific abnormal beats. These “abnormal” beats can be heard and guessed at by auscultation. But the ECG can accurately differentiate one from the other, indicating from where in the heart they are coming. (A Holter Monitor is a small ECG device for extended recording to “catch” occasional irregular heartbeats.) The ECG can also give information about the position of the heart in the chest, the strength of the heart, some metabolic and electrolyte abnormalities, or information about some drug overdoses. All of this information helps the clinician know what treatment is appropriate – the treatment for one condition being highly inappropriate for another condition. They might sound similar in the stethoscope, but are definitely different on the ECG.

The second test a primary care clinician might ask for is an echocardiogram. This test uses ultrasound waves to literally “see” the heart in action. This test can visualize the shape, size, position, and motion of structures of the heart in real time. The test is specifically looking for abnormal heart valve structure and function, abnormal heart configuration (like “holes” in the heart or abnormal heart wall thickness or thinness), and abnormal blood flow patterns through the heart. All of these can help to definitively explain some of the abnormal sounds the clinician hears in his stethoscope or some of the symptoms a patient is having – like shortness of breath or chest pain which are alarming, but can be caused by several very different problems.

Finally, another non-invasive test the clinician might order is an exercise stress test – also known as a stress ECG. With an ECG machine attached to the patient, they are exercised at increasingly stressful levels. The test is specifically looking for abnormal changes in the ECG while the patient’s heart goes faster and faster. These changes could indicate that the blood vessels which feed the heart muscle – the coronary arteries – are able to deliver blood to the heart muscle under normal conditions, but cannot do so while working under faster heart rates and increased work load on the heart muscle – under stress. 

These changes would indicate a partial blockage in the coronary arteries and would indicate the need for a more invasive procedure – putting a catheter in the coronary arteries, injecting dye, and looking for the specific place where the partial blockage is located – a cardiac catheterization and angiogram. This is the gold standard test for diagnosing partial or complete blockage of a coronary artery and would allow for specific treatment – which might include placing a small tube – a stent – in the partial blockage to hold it open or might indicate the need for a coronary by-pass graft – a CABG (CAB-bage) – to by-pass the blockage and restore blood flow to the heart muscle.

Each level of testing described becomes more necessary as the need for definitive diagnosis and treatment becomes more critical. Some heart problems are genetic or are as the result of aging and cannot be avoided. But many heart problems, especially in young people (under 65), can be prevented. Popular magazines are replete with articles on how this prevention is achieved. The real question is – how badly would you like to avoid, if possible, the frightening symptoms and the tests required to diagnose something that could have been avoided? It happens to hundreds of people – every day of the year, including February, National Heart Month. But you don’t have to be one of them.

Dr. Max Hammonds, MC, MPH, MHA, DABA is a retired anesthesiologist and public health lecturer.

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