Palpation of Cardiac Thrills — Systolic & Diastolic

General Technique for Palpating Thrills

• Patient supine initially; then rolled to the left lateral decubitus position (left side down) to bring the apex closer to the chest wall — essential for detecting diastolic thrills at the apex.
• For aortic/pulmonary area: patient may lean forward in expiration.

• Use the flat of the palm (metacarpophalangeal area) first to localize, then use fingertips to characterize.
• Press gently but firmly — excessive pressure dampens the vibration.

Systolic Thrills

1. Place the patient supine or leaning forward.
2. Palpate the aortic area (2nd right ICS) — a systolic thrill here strongly suggests aortic stenosis (AS). It may also radiate to the carotid arteries in the neck.
3. Palpate the pulmonary area (2nd left ICS) — a systolic thrill here suggests pulmonary stenosis or a large VSD.
4. Palpate the lower left sternal border (3rd–4th ICS) — systolic thrill here is characteristic of VSD.
5. Palpate the apex — a systolic thrill at the apex suggests mitral regurgitation (MR).
6. To time the thrill: simultaneously palpate the carotid pulse with one hand — a systolic thrill occurs at the same time as the carotid pulsation.

Braunwald's Heart Disease notes that palpation of the carotid pulses simultaneously with the precordium helps differentiate systolic murmurs and confirms the systolic thrill of AS.

Diastolic Thrills

1. Roll the patient into the left lateral decubitus position (right shoulder off the table, left shoulder down).
2. Palpate the cardiac apex (5th ICS, midclavicular line) with the fingertips.
3. A diastolic thrill at the apex (rare) indicates severe mitral stenosis (MS). Harrison's notes: "A diastolic thrill may very rarely be present at the cardiac apex, with the patient in the left lateral recumbent position."
4. Fuster and Hurst's confirms: "Palpation may reveal a diastolic thrill in the left lateral decubitus position" in mitral stenosis.
5. To time it: the diastolic thrill is felt after the carotid pulsation fades — in the interval between beats.
6. Palpate the left sternal border (2nd–3rd ICS) in expiration (patient leaning forward) — a rare diastolic thrill here may suggest severe aortic regurgitation or pulmonary regurgitation.

Summary Table

Key Tips

• Diastolic thrills are far less common than systolic thrills and require optimal positioning.
• Always compare timing with the carotid pulse: systolic = coincides; diastolic = follows.
• A thrill always implies a murmur of at least grade 4/6 intensity.
• Light, methodical palpation with the metacarpal heads (not fingertips) is most sensitive for initial detection.

Differentiating Systolic vs. Diastolic Thrills — Where and When to Palpate

The Core Principle: Timing with the Carotid Pulse

How to Use the Carotid to Time the Thrill

1. Place your right hand flat on the precordium over the area of interest.
2. Simultaneously place your left index + middle finger lightly over the right carotid artery (between larynx and sternomastoid).
3. Feel the carotid pulse — it rises and falls once per beat.
4. Correlate:
   • Thrill felt at the same moment the carotid rises → Systolic
   • Thrill felt after the carotid peak fades (in the quiet gap) → Diastolic

Braunwald's Heart Disease emphasizes that "palpation of the carotid pulses will elucidate the cause of the systolic murmur" and is the key timing reference in precordial examination.

Where to Palpate — Area by Area

1. Aortic Area — 2nd Right ICS, Right Sternal Border

• What to feel: Systolic thrill
• Cause: Aortic stenosis (AS) — radiation may extend to the carotid arteries as a carotid shudder
• When: Patient supine or leaning forward in expiration
• Braunwald's notes: "radiation of the murmur to the carotid arteries may result in a palpable thrill or carotid shudder" in severe AS

2. Pulmonary Area — 2nd Left ICS, Left Sternal Border

• What to feel: Systolic thrill
• Cause: Pulmonary stenosis, large ASD with pulmonary flow murmur
• When: Patient supine; lean forward slightly to bring RV closer to chest wall

3. Lower Left Sternal Border — 3rd–4th Left ICS

• What to feel: Systolic thrill
• Cause: Ventricular septal defect (VSD), LVOTO
• When: Patient supine; also in congenital heart disease with cyanosis (e.g., d-TGA + VSD)
• Fuster and Hurst's: "a systolic thrill may be felt when a VSD or severe left ventricular outflow tract obstruction are present"

4. Mitral Area (Apex) — 5th Left ICS, Midclavicular Line

• What to feel:
  • Systolic thrill → Mitral regurgitation (MR)
  • Diastolic thrill (rare) → Mitral stenosis (MS)
• When for systolic: Patient supine
• When for diastolic: Patient in left lateral decubitus position — this is mandatory; the apex rotates forward making the thrill palpable
• Harrison's: "A diastolic thrill may very rarely be present at the cardiac apex, with the patient in the left lateral recumbent position"
• Goldman-Cecil: Palpation in MS finds a "quiet apical impulse" with a parasternal lift if pulmonary hypertension develops; the diastolic thrill is felt at the apex with the patient turned left

5. Carotid Arteries (Neck)

• What to feel: Systolic thrill ("carotid shudder")
• Cause: Severe AS with radiation
• When: Lightly palpate both carotids during systole

Summary: When to Use Which Position

Quick Memory Aid

"Systolic = same as the carotid; Diastolic = delayed after the carotid" "Diastolic thrill = turn the patient left, feel the apex"