Cardiovascular Medicine - Education Center

Heart sounds:


Auscultation of the normal heart reveals 2 sounds which are known as the 1st (S1) and 2nd (S2) heart sounds respectively. These sounds probably originate from vibrations caused by the closing of the heart valves in combination with the quick variations in blood flow and the changes in tension within cardiac structures as the valves close.

Normal heart sounds
First and Second heart sounds

Mitral valve abnormalities
Mitral Stenosis
Mitral Regurgitation
Mitral Valve Prolapse alone
Mitral Valve Prolapse and Mitral Regurgitation

Aortic valve and vessel abnormalities
Aortic Stenosis
Aortic Regurgitation
Coarctation of the Aorta

Murmurs associated with arterio-venous (left-right) shunts
Patent Ductus Arteriosus
Atrial Septal Defect
Ventricular Septal Defect

Pulmonary valve abnormalities
Pulmonary Stenosis

Tricuspid valve abnormalities
Ebstein's Anomaly

The raw data behind the heart sounds on this page was provided by Synapse Publishing Incorporated. Then these sounds underwent extensive audio enhancements eg noise reduction, frequency enhancement etc at IMC. Finally, the phonocardiographic correlations were produced at IMC.

The Synapse-IMC Heart Sounds Joint Venture - yet another education service for you.

Electrocardiograms (ECGs):


These electrocardiograms are recorded on standard paper where the small squares are 1 mm in size and the large squares are 5 mm in size and the paper speed is 25 mm/s (5 large squares represent 1 s). The leads consist of the 3 standard leads I, II and III, the 3 unipolar limb leads AVR, AVL and AVF and the 6 precordial leads V1, V2, V3, V4, V5 and V6. Although much can be said about ECGs (several textbooks have been written about the topic), we shall stop this introduction here to examine some ECGs. The ECG files are rather large and will take some time to appear. We apologize for this although it is beyond our control and hope that your wait will be worthwhile.

Normal Sinus Rhythm

Sinus Bradycardia

Sinus Tachycardia

Atrial Fibrillation with Premature Ventricular Complexes

These electrocardiograms were provided by Dr Tan Huay Cheem, Senior Registrar, Cardiac Department, National University Hospital, Singapore. These ECGs were then scanned and the images were enhanced at IMC.

Chest X-rays:


These chest x-rays display the heart in various pathological states. Again, many complete books have been written on the interpretation of chest x-rays. However, a few points must be remembered - the correct patient must be matched to the correct x-ray on the correct day, the x-ray must be centered and interpreted correctly, the size of the normal heart must be less that half of the transthoracic diameter and the apex of the heart points to the left (except in dextrocardia). The x-ray images are large files and will take some time to appear. We thank you for your patience.

Mitral Stenosis

Multiple Valvular Abnormalities

These chest x-rays were provided by the Department of Diagnostic Imaging, Tan Tock Seng Hospital, Singapore. The x-ray films were then digitalized and enhanced at IMC.

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