BEDSIDE DIAGNOSIS OF SYSTOLIC MURMURS


Blinded study of bedside maneuvers to diagnosis systolic murmurs in 50 pts aged 6-85, ALL WITH DOCUMENTED VALVULAR DISEASE; there was 87% concordance between examiners on whether maneuvers increased, decreased, or didn't change intensity of murmurs. Diagnosis made by cardiac cath or echo. (NEJM 318:1572, 1988)

MOST USEFUL:

I. Inspiration

  1. All murmurs from right-sided lesions increased in intensity with inspiration and decreased during expiration. These changes were 100% sensitive and 88% specific for right-sided as opposed to other lesions
  2. Most left-sided murmurs decreased or no change with inspiration and increased or no change with expiration
  3. Physiologic explanation: increased venous return with inspiration increases R-heart but has little effect on L-heart filling

II. Valsalva maneuver (hold for 20sec; listen just before end of the strain phase)

  1. Increases 65% of the time with hypertrophic cardiomyopathy; decreased 30% of the time; Increased intensity 65% sensitive and 96% specific for hypertrophic cardiomyopathy as opposed to other lesions
  2. Most other murmurs decreased intensity during Valsalva
  3. Physiologic explanation: murmur intensity increases with decreased LV volume because of increased proximity of septum and mitral valve; decreased venous return with Valsalva

III. Passive leg elevation (straight leg raise to 45 degrees; listen after 15-20sec)

  1. Decreases 85% of the time with hypertrophic cardiomyopathy; decrease with leg raise 85% sensitive and 91% specific for hypertrophic cardiomyopathy as opposed to other lesions
  2. Other lesions mostly no change or increase in intensity with leg elevation
  3. Physiologic explanation: see II. C.

IV. Squatting to standing (squat for > 30sec then rapidly stand; listen during 1st 15sec of standing)

  1. Increases 95% of the time with hypertrophic cardiomyopathy; increase with this maneuver is 95% sensitive and 84% specific for hypertrophic cardiomyopathy as opposed to other lesions
  2. Other lesions tended to decrease or not change with this maneuver
  3. Physiologic explanation: see II.C.

V. Transient arterial occlusion (BP cuff around both upper arms, simultaneously inflated to 20-400mm Hg above systolic BP; listen after 20sec)

  1. Increases 80% of the time (and never decreased) with mitral regurgitation and VSD; increase with this maneuver 78% sensitive and 100% specific for one of these lesions as opposed to the others
  2. With other lesions, mostly no change or decrease
  3. Physiologic explanation: increases afterload, causing greater flow to these alternate routes to LV outflow

 

LESS USEFUL:

VI. Inhalation of amyl nitrite (one 0.3ml ampule; pt takes 3 rapid, deep breaths; listen 15-30sec after inhalation; don't do with critical aortic stenosis & others who can't tolerate sudden drop in BP!)

  1. Decreases 77% of the time with mitral regurgitation and 90% of the time with VSD; decrease with this maneuver is 80% sensitive and 90% specific for one of these lesions as opposed to the others
  2. Augments murmurs due to other lesions
  3. Physiologic explanation: a rapid vasodilator; produces systemic hypotension, decreasing afterload (see V.C.)

VII. Isometric handgrip (listen after 1 min of maximal contraction)

  1. Increases about 70% of the time with mitral regurgitation and VSD; though decreases (1) in 20% of each
  2. Decreases 85% of the time with hypertrophic cardiomyopathy
  3. No consistent effect (mostly no change or decrease) with aortic stenosis or right-sided murmur
  4. Physiologic explanation: this maneuver has multiple effects, including increased venous return, heart rate, cardiac output, and arterial pressure.

VIII. Muller maneuver (making forceful effort to inhale with glottis closed; the opposite of Valsalva): no consistent difference among its effects on different types of murmurs; tended to decrease intensity of all.