OUR PROCEDURES
Non Invasive Cardiology
- ECG / Electrocardiogram
- Ambulatory Blood Pressure Monitor
- Ambulatory ECG / Holter Monitor
- Echocardiogram / Echo
- Treadmill Stress Tests
- Stress Echocardiogram
- Echo / Contrast Echo Study
- Dobutamine Stress Echo
- 'Reveal' device interrogation
- Single and dual chamber pacemaker checks
- Biventricular pacemaker checks (CRT)
- Implantable defibrillator (ICD) checks
- External counter pulsation therapy
ECG / Electrocardiogram
This is a simple procedure that involves the application of electrodes to the chest to measure tiny electrical impulses generated by the heart to ensure it contracts and relaxes in an organised manner. It's considered the gold standard for cardiac arrhythmia diagnosis. Applications include a guide for risk stratification for patients with recent myocardial infarctions. The ECG is used as a screening tool for ischaemic heart disease and prior to operative procedures. It may also identify conduction disturbances, electrolyte imbalances, information on the hearts position, chamber sizes, pericardial compliance, lung disease and central nervous system depression. There is no risk associated with the procedure. No preparation by the patient is required.
Ambulatory Blood Pressure Monitor
This procedure involves the application of a blood pressure cuff to the non-dominant arm with BP recordings made at regular intervals. The monitor will indicate to the patient when it is about to inflate and has an override button if inflation of the cuff becomes uncomfortable. The cuff can also be easily repositioned by the patient if required. A patient dairy is issued to document daily activities for greater understanding of BP trends. The monitor's applications include an early diagnosis of hypertension and to ensure normal BP trends through the day and night. This may be used to prevent a patient progressing towards hypertensive heart disease and associated problems, or to assist better management of medication therapy. There is no risk associated with the procedure. No preparation by the patient is required.
Ambulatory ECG / Holter Monitor
This involves the application of three ECG electrodes and a monitor to capture every single electrical impulse whilst the device is worn. A patient dairy is issued to document daily activities for greater understanding of heart rate response. Any 'event key' can be pressed by the patient to mark a symptom on the recorded ECG. The monitor has greatest application in identifying arrhythmias as most patients will present with palpitations or syncope (black-outs). Appropriate pacemaker use and atrial fibrillation rate control are other examples of ECG monitor application. Depending on the frequency of the patient's symptoms, monitors can be applied for 24, 48, 72 hrs or a week. There is no risk associated with the procedure. No preparation by the patient is required.
Echocardiogram / Echo
Involves the application of an ultrasound probe with coupling gel to gather diagnostic information on the heart. Sound waves sent through the probe bounce off the structures within the body and return for the machine to generate a moving image. The applications of echo are vast and include evaluation of murmurs, investigation for congenital heart disease, valvular pathologies, heart failure, peripheral oedema (swelling of ankles), shortness of breath (with or without exertion) and risk stratification of ongoing management of patients with heart disease. Studies can also be tailored to view the effect of pacemakers and determining whether a biventricular pacemaker insertion (a pacemaker with three leads) will improve heart failure. There is no risk associated with the procedure. No preparation by the patient is required.
Treadmill Stress Tests
This procedure involves the application of electrodes similar to a standard ECG with the added component of physical exercise. This test is used as a screening tool for ischaemic heart disease, exercise induced arrhythmias, determining appropriate behaviour of a pacemaker or heart rate response of a patient with atrial fibrillation. Blood pressure is recorded at regular intervals to assess the response to exertion. The patient is normally required to fast three hours prior to minimise airway hazards.
Stress Echocardiogram
To further enhance the accuracy of treadmill testing incorporation of echo is applied directly to view the heart after exercise. Set images are taken prior and post exercise and compared, to view heart function. Identification of cardiomoypathies (heart muscle disease) or ischaemia can be made. If a patient experiences shortness of breath on exertion, pulmonary pressures can also be assessed post exercise to exclude a cardiac component. The patient is normally required to fast three hours prior to minimise airway hazards.
Echo Bubble / Contrast Study
A link has been documented that a 'hole in the heart' can be a potential cause of small strokes or nasty migranes. A patent foramen ovale can be difficult to distinguish by echo alone, but administering of agitated saline solution can easily identify this. If indicated the patient can undergo a simple procedure to close the defect. These tests are non-invasive but involve a needle to administer fluids for the procedure.
Dobutaimine Stress Echo
If a patient is unable to walk or if viability of heart muscle (after a heart attack) wishes to be determined, this procedure uses the increasing administration of Dobutmaine to mimic the effect of exercise. It is very similar to Adrenaline which is what the body normally produces during exercise to stimulate the heart. The drug is very short acting and side effects are quite rare and mild. These tests are non-invasive but involve a needle to administer fluids for the procedure. The patient is normally required to fast three hours prior as a precautionary measure.
'Reveal' device interrogation
These small, implantable ECG recorders are used for patients experiencing problematic symptoms but which occur so intermittently that conventional Holter monitoring for 24, 48 or even 72 hours, does not capture the events. The 'reveal' continuously monitors the heart rhythm and automatically stores events which it considers unusual. It can also be activated by the patient during an attack of symptoms by holding an activation device over the area where the reveal is implanted and clicking a button. The reveal can be quickly read or downloaded at the out patient clinic by the cardiac physiologist. Any unusual cardiac rhythms which the reveal may have recorded are then correlated to the patients' account of any symptoms and then given to the Cardiologist. The appointment will take about 15 - 20 minutes.
Single and dual chamber pacemaker checks
Pacemakers are implanted into patients who have heart rhythms which are different from healthy functioning hearts, either too slow or too irregularly. An implanted pacemaker can be either single or dual chamber depending on the underlying cardiac rhythm of the patient.
A pacemaker check is carried out at the time of implantation and also needs to be checked at regular intervals thereafter. The test is performed by a Cardiac Physiologist who analyses the data collected by the pacemaker in between checkups and uses the data to improve the efficiency of the pacemaker or to adjust the programmed settings according to the patients changing needs. Most pacemaker batteries last between 5 and 10 years, at the check the Physiologist will also be able to assess the battery status of the pacemaker and advise the Cardiologist when a new battery is required. A battery change involves changing the pacemaker box, but leaving the leads in the heart. The check takes about 15 - 30 minutes depending on the type of device. It is a quick and painless procedure which involves lying on a couch with ECG electrodes connected to the patients' wrists and ankles and having a small communication device placed over the pacemaker site. Following the check the physiologist will make a further outpatient appointment and send the results of the test to the Cardiologist
Biventricular pacemaker checks (CRT)
Pacemakers which are implanted in some patients with heart failure, a Bivent check is similar to a pacemaker check, it may take slightly longer as there is often a third electrode in the heart which needs to be checked. Again the check allows us to analyze many types of data that the device has collected in between visits and can give us information about, for example, whether particular drugs are effective and allows us to reprogram the settings according to the patients needs.
Implantable defibrillator (ICD) checks
ICD's are extremely effective at treating 2 potentially lethal rhythm abnormalities (Arrhythmias), VT and VF. When fully operational, ICD's monitor the heart rate and rhythm. When it detects an abnormality, it will initiate pacing if the rhythm is VT, or it will deliver a small electric shock if the rhythm is VF. This is because in VF, the heart rhythm is completely chaotic and it can no longer pump blood effectively around the body. An ICD check is similar for the patient to a pacemaker check, it may however take slightly longer as there is often a lot more data which needs to be analysed by the physiologist. Most importantly, ICD checks allow us to see whether the patient has received any shocks, therapy for VT or VF, to provide reassurance to the patient that the device is functioning as it should be and to make any adjustments to improve the efficiency of the device.
External counter pulsation therapy
ECP stands for External Counter Pulsation. It is an effective treatment for a form of angina called Chronic Refractory angina. This means that despite optimum medication and surgical intervention, a patient may still suffer from angina pain.
ECP works in a number of different ways. It reduces the resistance that the heart has to overcome before being able to pump blood to the body. This is known as afterload. It increases the amount of blood flowing through the coronary arteries during its resting phase (diastole), and increases the amount of blood returning to the right side of the heart. ECP appears to exert its coronary artery effects by increasing the amount of pressure in a narrowed artery, thereby opening up collateral channels around a blockage such as atheroma in heart disease. It also has a mild exercise effect on the heart. Athletes have well established collaterals, due to the amount of exercise that they have to undertake and their general level of fitness.
Inflatable cuffs are placed around the calves, thighs and buttocks. A continuous ECG is taken of the heart and analysed. Inflation and deflation of the cuffs is rapid and timed precisely to the ECG or heart rhythm. Treatment consists of 35 one hour sessions. Research conducted at a leading American university hospital has established that 35 hours is the optimum treatment time for this therapy. During its inception at the Wellington hospital, a research study was undertaken which also corroborated the previous findings. Most patients find that following completion of ECP, the amount of medication they need to take to control the angina pain is reduced significantly, with some able to cease nitrate spray completely. Exercise tolerance is also increased, with many patients reporting being able to resume activities that they previously had been unable to participate in.