Left Ventricular Hypertrophy

1
Left Ventricular Hypertrophy

• Detection, significance and treatment

2
Pathophysiology of LVH

• High BP ? ? LV wall stress
• Wall stress ? 1/ wall thickness
• LV wall thickening ? ? wall stress
• Myocyte hypertrophy and ? collagen matrix
• Mediators
• Mechanical preload afterload
• Neurohormonal angiotensin II, sympathetic NS

3
Methods of detecting LVH

• Clinical examination
• Chest radiography
• Electrocardiography
• Echocardiography
• (CT, MRI)

4
Definition of LVH

• Healthy cohort of subjects
• No high BP, diabetes, CV disease, obesity
• LVH defined as LVMI gt mean 2SD
• Framingham Study
• LVMI gt 131g/m2 males gt 100g/m2 females
• Cornell, New York
• LVMI gt 134g/m2 males gt 110g/m2 females

Levy et al. Am J Cardiol 198759956-60.
Devereux et al. JACC 198441222-30.
5
Risk factors for LVH

• Age
• Gender
• Race
• Genetic factors
• Blood pressure
• Obesity
• Physical activity

6
Clinic versus mean 24 hour systolic BP and LVMI
Mayet al et. J Cardiovasc Risk 19952255-61.
7
12-lead ECG showing LVH and strain
8
Sensitivity and specificity of ECG criteria for
LVH
Devereux et al 1983, Murphy et al 1985, Levy et
al 1990, Lee et al 1992, Devereux et al
1993, Schillaci et al 1994, Crow et al 1995,
Norman et al 1995, Chapman et al (in press)
9
Determinants of specificity of ECG criteria for
LVH

• Age
• Race
• Sex
• Smoking
• Obesity

10
Cardiothoracic ratio and CHD mortalityWhitehall
study
Adjusted for age, BP, HR, cholesterol, smoking,
angina and ECG ischaemia
Hemingway et al. BMJ 1998 316 1353-4.
11
Cardiovascular risk in subjects with ECG-LVH
Framingham
Age-adjusted risk-ratio
Plt0.0001
Kannel. Eur Heart J 1992 13 (suppl D) 82-88
12
Risks of X-ray and ECG LVHFramingham
Age-adjusted biennial rate per 1000
Data include men and women, aged 35-94
Kannel. Eur Heart J 1992 13 (suppl D) 82-88
13
Echocardiography

• Advantages
• sensitivity
• improved correlation with morbidity mortality
• assessment of function (systolic and diastolic)
• addition to individuals risk profile
• Disadvantages
• skilled operator
• time
• cost

14
Echocardiographic LVH and prognosis
Sheps and Frohlich. Hypertension 1997 29
560-563.
15
M-mode echocardiograms
LVH
Normal
16
Penn convention for M-mode measurements

• Peak of QRS
• Endocardium excluded from SWT and PWT
• Endocardium included in LVID
• LV mass 1.04(SWTLVIDPWT)3 - (LVID)3 - 14g
• Divide by body surface area to get LV mass index

Septum (SWT)
LV cavity (LVID)
Posterior wall (PWT)
Devereux Reichek Circulation 197755613-8
17
ASE guidelines for M-mode measurements

• Start of QRS
• Endocardium included in SWT and PWT
• Endocardium excluded from LVID
• LVM 0.81.04 (SWTLVIDPWT)3 - (LVID)3 0.6
  g
• Divide by body surface area to get LV mass index

Septum (SWT)
LV cavity (LVID)
Posterior wall (PWT)
Devereux et al. Am J Cardiol 198657450-8
18
Area-length method for calculation of LV mass

• LVmass1.055/6(A1xL1)-5/6(A2xL2)
• Divide by body surface area to get LV mass index
• Reichek et al. Circulation 198367348-52

19
4-year age-adjusted incidence of cardiovascular
disease according to LVMI
Age-adjusted incidence/ 100 subjects
LVMI (g/m2)
Redrawn from Levy et al NEJM 1990 322 1561-6.
20
Incidence of cardiovascular mortality according
to presence or absence of LVH
Pns
Plt0.001
Redrawn from Levy et al, NEJM 1990 322 1561-6.
21
Echocardiographic LVH and prognosis
Sheps and Frohlich. Hypertension 1997 29
560-563.
22
Risks associated with LVM and geometry
Cardiovascular events
Total mortality
patients
RWT
LVMI (g/m2)
LVMI (g/m2)
Plt0.001, P0.03
Koren et al. Ann Int Med 1991 114 345-352.
23
Regression of LVH by drug treatmentmeta-analysis
of RCTs
Mean ? in LVMI
Between treatment Plt0.01
Schmieder et al. JAMA 1996 275 1507-1513
24
LVH regression LIVE study
? from baseline

Plt0.05 for LVMI
Sheridan and Gosse 1998
25
Prognostic significance of Echo LVM regression

Events/ 100 patient years

P0.04, P0.0004 after adjustment for age.
Verdecchia et al. Circulation 1998 97 48-54
26
Prognostic significance of ECG voltage changes
Framingham

OR for CV events (2 years)

Plt0.05
Levy et al. Circulation 1994 90 1786-1793
27
Who to refer for echocardiography?

• Patients with borderline BP
• LVH may influence decision to treat
• Patient with multiple risk factors
• LVH may lead to other interventions e.g. lipid
  lowering therapy
• Possible white coat hypertension
• ? To stratify class of antihypertensive agent to
  be used (increasing data suggesting LVH
  regression should be a goal of treatment)