EKG or electrocardiography is the recording of the graphics of electrical potential variations caused by the heart's muscular electrical activity and detected on the surface of the body. EKG's work principles are recording electrical signals related to the heart's activity and resulting a graph of recorded voltages to time.

EKG is a method to learn the performance of cardiac muscles that it may support the diagnosis of the heart's abnormality and the heart's functionality tendency or change.

Electrocardiograph is a tool to perform electrocardiography, while electrocardiogram is the paper on which the graphic of electrical potential variations due to cardiac muscles excitation detected on the surface of the body are recorded.

Normal electrocardiogram suggests the deflection resulted by atrial and ventricular activities as the change of voltage and polarity (positive and negative) tendencies to time. The first deflection or P wave is the result of atrial excitation QRS complex deflection is the result of ventricular excitation (depolarization) T wave is the result of ventricular recovery (repolarization).

Critical factors affecting EKG test are:

1. Incorrect placing of electrode or electrode's not being firmly attached to the skin may affect the accuracy of EKG record.
2. The temperature around the test area must be maintained in the range of 20-25oC and the humidity must be low.
3. EKG test must be performed away from tools producing noise such as equipments of ultrasonography, X-ray, mobile phone or other electrical tools.
4. The patient must be calm, unmoved and quiet during the test. The patient's legs and arms are ascertained not to be in contact with any metal.
5. The data of patient's age and sex have to be correct since several kinds of EKG tools interpret the result under the consideration of age and sex.
6. Put away any stuff containing metal such as watch, mobile phone, key, etc.
7. The patient is not allowed to do exercise preceding the test.

Treadmill is a nonstop EKG recording. The function is to assess the heart's condition by recording it while doing physical exercise. Apart from detecting arrhythmia, treadmill can also be used as a screening test capable of detecting whether there is a narrowed coronary artery resulting in limited oxygen supply to the heart muscles.

Patient's preparation prior to doing treadmill:

1. Skipping meal and drink (except snack and plain water) at least 4 hours before the test to reduce nausea and vomiting.
2. Wearing loose and comfortable clothes and shoes.
3. The patient is suggested to drink specific heart medicines 1-2 days before the test.

The test is not allowed in the following conditions:

1. Acute myocardial infarction or myocardial infarction complication
2. Significant EKG result change showing infarct condition or acute heart condition
3. Unstable angina
4. Congestive heart failure
5. Ventricular or atrial dysrhythmia
6. Having a history of using drugs such as digoxin, diuretic, sedative, psychotropic
7. Aortic stenosis or left ventricular hypertrophy
8. Suspected aneurism
9. Myocarditis or myocardiopathy
10. Active thrombophlebitis
11. Systemic or lung embolism in the past 3 months
12. Currently suffering from infection disease

Thoracic imaging, or what is often called as chest X-ray (CXR) is a radiographic projection of the thorax intended to diagnose the conditions affecting the thorax, its contents and the nearby structures. CXR uses ionized radiation in the form of X-ray. In order to form a radiograph, the dosage of radiation for adults is around 0.06 mSv.

CXR is used to diagnose numerous conditions involving thoracic wall, thoracic vertebrae, and the structures within the thoracic cavity, including the lung, heart and great vessels. Pneumonia and congestive heart failure are often diagnosed by CXR. CXR is often used for the screenings of pulmonary diseases related to industrial works such as mining where the workers are exposed to dust.

In general, the functions of CXR are:
- to observe congenital abnormalities (the heart, vascular)
- to observe the presence of trauma (pneumothorax, hemothorax)
- to observe the presence of infection (generally tuberculosis/TB)
- to check the heart' s condition
- to check the lung' s condition

In some conditions, CXR is suitable for screening, but not for diagnosing. At times when, based on the CXR, abnormalities are suspected, additional thoracic imaging test can be performed to obtain a surer diagnosis or evidences supporting the CXR diagnosis.

Different images of the thorax can be obtained by altering the body' s relative orientation and the direction of X-ray. The most common images are posteroanterior (PA), anteroposterior (AP) and lateral.

1. Posteroanterior (PA)

In PA, X-ray source is positioned so as to it comes in from the posterior (back) part of the thorax and comes out from the anterior (front) part where it will be detected. To get this image, an individual stands facing a flat surface that functions as X-ray detector. Radiation source is placed behind the patient at a standard distance, and the X-ray is then transmitted to the patient.

2. Anteroposterior (AP)

In AP, the position of X-ray and detector is the opposite of PA. AP chest X-ray is harder to interpret than PA, and therefore it is used in a situation where it is difficult to get a normal chest X-ray due to the patient' s inability to get up from the bed. In such situation, mobile X-ray is used to get a lying down CXR ("supine film"). As a result, most supine films are also AP.

3. Lateral

Lateral image can be obtained using similar methods employed in PA, but in lateral the patient stands with both arms raised and the left side of the thorax being pressed against a flat surface.

Abnormalities usually spotted through CXR are:

1. Nodule (a distinct spot on the lung)

It is usually caused by benign/malignant neoplasm, granuloma (tuberculosis), infection (pneumoniae), vascular infarction, varix, Wegener' s granulomatosis and rheumatoid arthritis. The growth speed, classification, shape and location of a nodule can assist in the diagnosis. The nodule can be many.

2. Cavity

Cavity is a walled hollow structure within the lung. It is usually caused by cancer, pulmonary embolism, Staphylococcus aureus infection, tuberculosis, Klebsiella pneumoniae, anaerobic bacteria and fungi, and Wegener' s granulomatosis.

3. Pleural abnormality

Pleural fluid is a fluid existing between the lung and the thoracic wall. Pleural effusion can occur on cancer, sarcoid, connective tissue disease and lymphangioleiomyomatosis.

Though CXR is a cheap and relatively safe method, there are several severe thoracic conditions that may give a normal CXR result, such as the result of a patient with acute myocardial infarction.

Audiometry is a test aiming at knowing the level/threshold of one's hearing and its disorder if any. This test is performed by using a pure tone audiometer inside a sound-proof room.

The principle is that various sound frequencies and intensities (dB) are transferred through headset or bone conduction to one's ear or mastoid, and then the threshold of sound intensity (dB) which is unable to be heard by the patient is recorded, through computer program or being plotted manually on graphic paper.

Benefits of audiometry:

• to figure out the degree of hearing loss: mild, moderate or severe
• to figure out the type of hearing loss: conductive, sensorineural or mixed

Test indications:

1. Hearing degradation
2. Ringing in the ear (tinnitus)
3. Sensation of repletion in the ear
4. Record of ear drainage
5. Record of exposure to noise
6. Record of trauma
7. Record of ototoxic medication
8. Record of hearing disorders within family
9. Balance disorders

Degree of hearing loss parameter:

• Mild hearing loss: 26-40 dB
• Moderate hearing loss: 41-60 dB
• Severe hearing loss: 61-90 dB
• Profound hearing loss: > 90 dB

The reports of the result are normal hearing threshold, hearing threshold with conductive loss, hearing threshold with sensorineural loss, hearing threshold with mixed loss.

Spirometry is a test performed to objectively measure lung capacity/function (ventilation) on the patients with medical indications. The tool used in this test is called a spirometer.

Objective

1. to statistically and dynamically measure the lung volume
2. to assess the change or abnormality in pulmonary function

Basically, spirometry measures the speed of air volume change within the lung during forced respiration which is known as forced volume capacity (FVC). The most common procedure used is the one where the subject performs maximum inspiration and exhales as fast and as whole as possible. FVC value is compared to normal value and prediction valued based on age, body height and sex.

Prior to doing spirometry, anamnesis, as well as body height and weight measurement are performed with the patient. In spirometer, there is a prediction value for Asians based on age and body height. If the prediction value does not conform with Indonesian standard, adjustment will be done using the Indonesian standard. The resulting air volume will be calculated as a percentage of prediction value achievement.

Spirometry can be done in the form of social vital capacity (SVC) or forced vital capacity (FVC). In SVC, the patient will be asked to breathe normally for 3 times (mouthpiece is already put in mouth) before taking a deep breath and exhale to the fullest extent. In FVC, the patient is asked to take a deep breath before the mouthpiece is put into the mouth and the air is exhaled maximally.

Reported lung function measurement:

1. Forced vital capacity (FVC) is the amount of air that can be forcefully exhaled after maximum inspiration. It is measured in liter.
2. Forced expiratory volume in one second (FEV1) is the amount of air that can be exhaled in 1 second. It is measured in liter. Together with FVC, this is the main indicator of the lung function.
3. FEV1/FVC is the ratio of FEV1/FVC. In healthy adults, the value is around 75% - 80%.
4. Forced expiratory flow (FEF) 25-75%, optional
5. Peak expiratory flow (PEF), is the speed of air movement when it comes out of the lung at the beginning of expiration, measured in liter/second.
6. FEF 50% and FEF 75%, optional, is the average flow (speed) of air coming out of the lung in the middle of breathing process (often called as maximal mid-expiratory flow [MMEF]).

Classification of ventilatory defect (% predictive value):

Restrictive defect: Vital capacity (VC) < 80% predictive value FVC < 80% predictive value
Obstructive defect: FEV1 < 80% predictive value FEV1/FVC < 75% predictive value
Restrictive and obstructive defect: FVC < 80% predictive value FEV1/FVC < 75% predictive value

Spirogram is the result of spirometry. Several factors causing a spirogram to not qualify are:

1. Using the wrong method in taking a breath, or exhaling too fast
2. Coughing
3. Early termination
4. The closure of glottis
5. Varied expiration
6. Leak

Each measurement should be done at least 3 times. The criteria for a reproducible spirogram (after 3 times of expiration) is the two values of FVC and FEV1 from 3 expiration performed having minimum variation/difference (the difference is less than 5% or 100 mL).

Ultrasonography (USG) is a diagnostic technique of imaging by the means of ultrasonic, which is a sound wave with a frequency higher than human hearing ability. This technique is used to image internal organs and muscles, their sizes and structures. Generally, the purpose of USG is to help enforcing the diagnosis in various disorders of body organs.

USG test uses the sound waves with the frequencies of 1-10 MHz. The choice of frequency determines image resolution and penetration into the patient's body. The high frequency sound wave is generated from the crystals inside a tool called transducer/probe. The transformation resulted from mechanical force toward the crystals will generate electrical voltage this phenomenon is called Piezoelectric effect. The form of the crystals will also transform if it is affected by electrical field. The crystals will inflate and deflate according to the pattern of electrical field which goes through them so that a high frequency sound wave is generated.

One of the examples of ultrasonography is obstetric sonography used by obstetrician to predict the age of pregnancy, to estimate the date of confinement and to help finding disorders in the fetus.

Before performing USG test, the preparation steps the patient has to take are as follows:

1. People suffering from obstipation should better be medicated by laxative in the previous evening.
2. Test upon organs of upper abdominal cavity should be performed in the condition of fasting besides, in the morning, the patient is prohibited to eat and drink substances that may cause gas in stomach since the image of the organs being checked may be blurred.
3. For gallbladder test, the patient is suggested to do fasting at least 6 hours before the test, thus maximal passive dilatation can be obtained.
4. Obstetric and pelvic tests require the bladder to be full.