Cardiac thrill

What is Thrills?
Causes of thrill in different areas
How to determine the timing of a thrill ?

Causes of thrill in different areas

Causes of Aortic Thrills
Causes of Pulmonary Thrills
Causes of Left Lower Parasternal Thrills
Causes of Apical /mitral Thrills

What is Thrill

• Thrills are palpable vibrations in time with cardiac cycle.
• They are palpable equivalents of heart murmurs.
• The presence of a thrill indicates that the murmur is most of the time organic. 
• Low pitched murmurs of stenotic lesions will produce thrill better than the high pitched murmurs of incompetent lesions
• Stenotic murmurs produce low pitched thrills.
• Regurgitant murmurs produce high pitched thrills

As a general rule apical thrills are diastolic and basal thrills systolic.
However, apical thrill may be systolic (as in severe MR) and basal thrills may be diastolic (as in acute severe AR).
Carotid Thrill (Carotid Shudder)
In aortic stenosis, systolic thrill (Carotid shudder) is palpated over the carotids.
Two type of thrill 

• Systolic thrill are felt along with apical impulse
• Diastolic thrill  A thrill ending in apical impulse is called as diastolic thrill

Pericardial rub - can be palpated as leathery rub

Bruit over the carotid - can be felt in aortic Stenosis

Venous hum at the root of the neck in anemia

Bruit over the interscapular region is seen due to dilated  posterior intercostal artery - in coarctation of aorta.

Thrill in different area

Area            Systolic       Diastolic        Continuous
Apex            MR  MS
LLSB          VSD             RSOV
2nd LICS    ASD, PS       AR/PR             PDA
2nd RICS     AS

How to determine the timing of a thrill ?

While palpating for a thrill, you should always put your left thumb over the right carotid artery at the level of upper border of thyroid cartilage  to confirm the timing of thrill .
If the thrill is synchronous with carotid pulsation it is systolic
Thrill occuring before the carotid pulsation is diastolic
Timing can also be done comparing thrill with apex beat
Always remember :
In mitral or apical area — Diastolic thrill is very common.
In all other areas (base of the heart and tricuspid area) — Systolic thrill is more common.
In pulmonary area — Thrill may be continuous or systolo-diaslolic. eg. PDA.

Apical /mitral Thrills

Apical Diastolic thrill    

• Mitral stenosis
• Left atrial myxoma rare

Apical Systolic thrill  

• Mitral regurgitation 
• Aortic stenosis (as sometimes, aortic events are best appreciated in the mitral
• VSD
• ASD (ostium primum)

Carey  Coombs' murmur and Austin Flint murmur are not associated with a thrill.

Left Lower Parasternal Thrills

Left Lower Parasternal Thrills( Left sternal border/tricuspid)
Systolic thrill

• Ventricular  septal defect
• Tricuspid incompetence
• ASD (Ostium primum) 
• Pulmonary stenosis (infundibular type)

Causes of Pulmonary Thrills

Pulmonary Systolic thrill

• Pulmonary stenosis
• Atrial septal defect 
• Ventricular septal defect
•  Patent ductus arteriosus
•  Fallot’s tetralogy

Continuous thrill

•   Patent ductus arteriosus
•   Rupture of sinus of Valsalva.

Causes of Aortic Thrills

Systolic thrill    -   Aortic stenosis
Diastolic thrill   -   Acute severe AR  due to eversion, infection or perforation of the valve
                              Syphilitic aortic regurgitation.