Non Interventional Cardiology

The Non-Interventional Cardiology is diagnostic testing for patients with suspected cardiac problems.

There are a variety of different tests that the cardiac physiologists can carry out to evaluate the condition of your heart and diagnose any problems. None of them involve incisions to your body.

Tests include ECGs, exercise tolerance testing, tilt table testing, Holter monitoring and echocardiography.

We also follow up patients who have been fitted with devices such as pacemakers and inplantable cardioverter defibrillators (ICDs).

The Non-Invasive Cardiology unit has some of the most advanced diagnostic equipment in the country and is renowned for its work alongside Southampton's other Cardiothoracic departments, such as Interventional Cardiology, Cardiac Surgery and Cardiac Rhythm Managements


The purpose of this study is to determine the size of your heart, to evaluate how well your heart is functioning or pumping and to assess the structure and function of the valves within the heart. A 2-D (or two-dimensional) echocardiogram is capable of displaying a cross-sectional "slice" of the beating heart, including the chambers, valves and the major blood vessels that exit from the left and right ventricle.

A Doppler echocardiogram measures the speed and direction of the blood flow within the heart. It screens the four valves for leaks and other abnormalities. By assigning color to the direction of blood flow, (Color Flow Mapping), large areas of blood flow may be studied. These color flow mappings allow abnormal blood flow characteristics to be interpreted by the cardiologist.

What will happen during the test

The test will take about 45 minutes. You will be asked to remove your shirt or blouse and put on a gown or a sheet to keep you comfortable and maintain privacy. After lying on an examination table, the technician will apply a colorless gel to your chest. The transducer will be moved back and forth across your chest to obtain several views of your heart.

You may be asked to move from your back and to the side. Instructions may also be given for you to breathe slowly or to hold your breath. This helps in obtaining higher quality pictures. With Doppler echocardiograms, as the transducer moves over your heart, you will hear a "whooshing" sound, much like that of a washing machine. This sound relates to the movement of blood within your heart chambers.

The images are constantly viewed on the monitor and recorded for a permanent record of the examination. This is reviewed by the physician prior to completion of the final report.

What is the preparation for the test?

Other than wearing loose-fitting clothing, there are no special restrictions or preparation prior to a 2D Doppler echocardiogram. Although the gel is water soluble and should not stain; it is messy and could get on your clothing so please be aware and dress appropriately.


A Stress Echo is a test that allows the physician to evaluate your heart under stress conditions with the use of a treadmill and ultrasound. This test will produce images that are very helpful in detecting a variety of heart problems, especially coronary artery disease. This test is also called an Exercise Echocardiogram.

An Exercise Echocardiogram test is divided into 3 parts.

Before the test begins, you will have several electrodes (small, sticky patches) placed on your chest and a baseline electrocardiogram (ECG) will be done. The Echocardiography Technologist will first perform an echocardiogram at rest.

To do this, a small device called a transducer is held against your chest with ultrasound gel while you lie on your left side with your left arm up. To improve the quality of the pictures, you may be asked to hold your breath in or out and not to speak at certain times.

The procedure is not painful, but the transducer may cause an uncomfortable feeling of pressure as it is positioned on your chest. The room will be darkened during the echocardiogram.

Next, you will be asked to walk on a treadmill. The average walking time is 6 to 10 minutes. Your blood pressure and ECG will be recorded several times throughout this test. The treadmill will start slowly and then gradually increase speed and incline. You will continue walking until you are either too tired to continue, you have reached your target heart rate or the Cardiologist or his/her designee has obtained adequate information. You will be asked to report any symptoms such as chest pain or shortness of breath. The test may be stopped if you experience these symptoms.

Immediately after you have finished walking on the treadmill, the final echocardiogram will be done.

Again, you will lie on your left side while the transducer is placed on your chest to record pictures. When the procedure is complete, the gel and sticky patches will be removed. During the exercise portion of your test, the Cardiologist, or Exercise Physiologist, Nurse Practitioner or Physician Assistant will be present. At the completion of the test, the Cardiologist will evaluate all the pictures and information.


An electrocardiogram (ECG) is a medical test that detects cardiac (heart) abnormalities by measuring the electrical activity generated by the heart as it contracts. The machine that records the patient’s ECG is called an electrocardiograph.

The electrocardiograph records the electrical activity of the heart muscle and displays this data as a trace on a screen or on paper. This data is then interpreted by a medical practitioner.

ECGs from normal, healthy hearts have a characteristic shape. Any irregularity in the heart rhythm or damage to the heart muscle can change the electrical activity of the heart so that the shape of the ECG is changed. A doctor may recommend an ECG for patients who may be at risk of heart disease because there is a family history of heart disease, or because they smoke, are overweight, or have diabetes, high cholesterol or high blood pressure

Heart Problems diagnosed by ECG

  • Enlargement of the heart
  • Congenital heart defects involving the conducting (electrical) system
  • Abnormal rhythm (arrhythmia) – rapid, slow or irregular heart beats
  • Damage to the heart such as when one of the heart’s arteries is blocked (coronary occlusion)
  • Poor blood supply to the heart
  • Abnormal position of the heart
  • Heart inflammation – pericarditis or myocarditis
  • Cardiac arrest during emergency room or intensive care monitoring
  • Disturbances of the heart’s conducting system
  • Imbalances in the blood chemicals (electrolytes) that control heart activity.


It is common to find heart patients who have normal ECG. One must remember that the ECGs are taken at rest when the heart is beating at its lowest rate. Even with 90% blocks the patients can have a normal ECG. In such cases the patient would also agree that at rest there is no pain in the chest, the angina symptoms would only come when they increase the heart rate, while doing some physical exertion like walking.

This is the condition where we need a TMT test. The patients are to gradually increase their heart rate, thus increasing the blood requirement of the heart muscles. Simultaneously ECG records are taken. If there is a blockage of approximately more than 70% ECG shows changes, suggestive of Angina.

Patients have to physically exert for this test which uses a computerised machine. The level of the exercise is gradually increased according to a standard protocol called the Bruce's Protocol. The continuous ECG monitoring during the exercise would reflect any blood and oxygen deficit in the muscles of the heart during exercise. The patient is asked to stop exercising as soon as ECG changes appear or any symptoms of chest pain or discomfort or breathlessness are felt.

TMT test is also called Exercise Stress Test, Computerised Stress Test or simply Stress test. This is the most easy, popular and common test performed on heart patients to determine the severity of the heart disease. Taken at an interval, this test can also show the improvement or deterioration of patient's angina.

A negative TMT or Stress Test is declared when the patient can reach a certain heart rate without showing any ECG changes. This rate is called a target heart rate and is calculated by a formula (Target Heart Rate = 220 - age of patient). If this rate is reached by the patient without producing any ECG changes, though the TMT can be called negative, but it would not mean that the blockage is zero. It will only mean that the person performing the test probably has a blockage less than 70%


A Holter monitor is a battery-operated portable device that measures and tape records your heart’s activity ECG continuously for 24 to 48 hours or longer depending on the monitor used. The device is the size of a small camera. It has wires with silver dollar-sized electrodes that attach to your skin. The Holter monitor and other devices that record your ECG as you go about your daily activities are called ambulatory electrocardiograms.

The Holter's most common use is for monitoring heart activity ECG, but it can also be used for monitoring brain activity EEG. Its extended recording period is sometimes useful for observing occasional cardiac arrhythmias or epileptic events which would be difficult to identify in a shorter period of time. For patients having more transient symptoms, a cardiac event monitor which can be worn for a month or more can be used.When used for the heart, (much like standard electrocardiography) the Holter monitor records electrical signals from the heart via a series of electrodes attached to the chest. Electrodes are placed over bones to minimize artifacts from muscular activity. The number and position of electrodes varies by model, but most Holter monitors employ between three and eight. These electrodes are connected to a small piece of equipment that is attached to the patient's belt or hung around the neck, and is responsible for keeping a log of the heart's electrical activity throughout the recording period.

Quick facts:

  • You may be asked to wear a Holter monitor to see if you have a slow, fast or irregular (uneven) heartbeat. Or, your doctor may use it to see how well your medicines are working to treat these problems. If you have a pacemaker and feel dizzy, your doctor may use a Holter monitor to find out if your pacemaker is working properly.
  • This monitor has no risks and wearing it isn’t painful.
  • The results of wearing a Holter monitor will help you and your doctor decide if you need more tests or medicines for your heart, or if you need a pacemaker or Cardioversion procedure to restore a regular heart rhythm.


Ambulatory blood pressure monitoring (ABPM) is a non invasive method of obtaining BP readings over twenty-four hours, whilst the patient is in their own environment, representing a true reflection of their blood pressure.

Many studies have now confirmed that blood pressure measured over a 24-hour period is superior to clinic blood pressure in predicting future cardiovascular events and target organ damage. Blood pressure is measured over twenty-four hours using auscultatory or oscillometry and requires use of a cuff. The monitor takes blood pressures every 20 minutes (less frequently overnight, eg 1-hourly).

What are the uses of ambulatory blood pressure monitoring?

  • To obtain a twenty-four hour record - more reliable than one-off measurements. Studies have shown that increased blood pressure readings on ABPM are more strongly correlated to end-organ damage than one-off measurements, eg LVH
  • To detect white coat hypertension.
  • It has use in hypertension research, eg reviewing 24-hour profile of antihypertensive medication.
  • It may have prognostic use - higher readings on ABPM are associated with increased mortality.
  • Response to treatment.
  • Masked hypertension.
  • Episodic dysfunction.
  • Autonomic dysfunction.
  • Hypotensive symptoms whilst on antihypertensive medications.
  • It may be more cost-effective in the long-term.


Signal-averaged electrocardiography (SAECG) is a technique involving computerized analysis of segments of a standard electrocardiogram that allows the detection of ventricular late potentials. Ventricular late potentials in patients with cardiac abnormalities, especially coronary artery disease or following an acute myocardial infarction (MI), have been associated with an increased risk of ventricular tachyarrhythmias and sudden cardiac death. Proponents of SAECG claim that it can obviate the need for invasive techniques commonly used to identify high-risk patients for interventions that treat or prevent ventricular tachyarrhythmia and sudden death.


A specialized clinic to install pacemaker. A pacemaker is a small device that's placed in the chest or abdomen to help control abnormal heart rhythms. This device uses electrical pulses to prompt the heart to beat at a normal rate. Pacemakers are used to treat arrhythmia.

Arrhythmias are problems with the rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm. A heartbeat that's too fast is called tachycardia. A heartbeat that's too slow is called bradycardia .

During an arrhythmia, the heart may not be able to pump enough blood to the body. This can cause symptoms such as fatigue (tiredness), shortness of breath, or fainting. Severe arrhythmias can damage the body's vital organs and may even cause loss of consciousness or death.A pacemaker can relieve some arrhythmia symptoms, such as fatigue and fainting. A pacemaker also can help a person who has abnormal heart rhythms resume a more active lifestyle.

Your heart has its own internal electrical system that controls the rate and rhythm of your heartbeat. With each heartbeat, an electrical signal spreads from the top of your heart to the bottom. As the signal travels, it causes the heart to contract and pump blood.

Each electrical signal normally begins in a group of cells called the sinus node or sinoatrial (SA) node. As the signal spreads from the top of the heart to the bottom, it coordinates the timing of heart cell activity.

First, the heart's two upper chambers, the atria, contract. This contraction pumps blood into the heart's two lower chambers, the ventricles. The ventricles then contract and pump blood to the rest of the body. The combined contraction of the atria and ventricles is a heartbeat.


A Close check-up for the heartbeat. An irregular heartbeat is an arrhythmia (also called dysrhythmia). Heart rates can also be irregular. A normal heart rate is 50 to 100 beats per minute. Arrhythmias and abnormal heart rates don't necessarily occur together. Arrhythmias can occur with a normal heart rate, or with heart rates that are slow (called bradyarrhythmias -- less than 50 beats per minute). Arrhythmias can also occur with rapid heart rates (called tachyarrhythmias -- faster than 100 beats per minute).


Heart failure does not mean the heart has stopped working. Rather, it means that the heart's pumping power is weaker than normal. With heart failure, blood moves through the heart and body at a slower rate, and pressure in the heart increases. As a result, the heart cannot pump enough oxygen and nutrients to meet the body's needs. The chambers of the heart respond by stretching to hold more blood to pump through the body or by becoming more stiff and thickened. This helps to keep the blood moving for a short while, but in time, the heart muscle walls weaken and are unable to pump as strongly. As a result, the kidneys often respond by causing the body to retain fluid (water) and sodium. If fluid builds up in the arms, legs, ankles, feet, lungs or other organs, the body becomes congested, and CHF is the term used to describe the condition.