Left Ventricular Hypertrophy Detection significance and treatment Pathophysiology

Left Ventricular Hypertrophy Detection, significance and treatment

Pathophysiology of LVH l l l High BP LV wall stress Wall stress 1/ wall thickness LV wall thickening wall stress Myocyte hypertrophy and collagen matrix Mediators: l l Mechanical: preload & afterload Neurohormonal: angiotensin II, sympathetic NS

Methods of detecting LVH l l l Clinical examination Chest radiography Electrocardiography Echocardiography (CT, MRI)

Definition of LVH l l l Healthy cohort of subjects No high BP, diabetes, CV disease, obesity LVH defined as LVMI > mean + 2 SD l l Framingham Study LVMI > 131 g/m 2 males; > 100 g/m 2 females Cornell, New York LVMI > 134 g/m 2 males; > 110 g/m 2 females Levy et al. Am J Cardiol 1987; 59: 956 -60. Devereux et al. JACC 1984; 4: 1222 -30.

Risk factors for LVH l l l l Age Gender Race Genetic factors Blood pressure Obesity Physical activity

Clinic versus mean 24 hour systolic BP and LVMI Mayet al et. J Cardiovasc Risk 1995; 2: 255 -61.

12 -lead ECG showing LVH and strain

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)

Determinants of specificity of ECG criteria for LVH l l l Age Race Sex Smoking Obesity

Cardiothoracic ratio and CHD mortality: Whitehall study *Adjusted for age, BP, HR, cholesterol, smoking, angina and ECG ischaemia Hemingway et al. BMJ 1998; 316: 1353 -4.

Cardiovascular risk in subjects with ECG-LVH: Framingham Age-adjusted risk-ratio *P<0. 0001 Kannel. Eur Heart J 1992; 13 (suppl D): 82 -88

Risks of X-ray and ECG LVH: Framingham Age-adjusted biennial rate per 1000 Data include men and women, aged 35 -94 Kannel. Eur Heart J 1992; 13 (suppl D): 82 -88

Echocardiography l Advantages l l l sensitivity improved correlation with morbidity & mortality assessment of function (systolic and diastolic) addition to individual’s risk profile Disadvantages l l l skilled operator time cost

Echocardiographic LVH and prognosis Sheps and Frohlich. Hypertension 1997; 29: 560 -563.

M-mode echocardiograms LVH Normal

Penn convention for M-mode measurements l Septum (SWT) l l Peak of QRS Endocardium excluded from SWT and PWT Endocardium included in LVID LV cavity (LVID) LV mass = 1. 04[(SWT+LVID+PWT)3 - (LVID)3 - 14 g Posterior wall (PWT) Divide by body surface area to get LV mass index Devereux & Reichek Circulation 1977; 55: 613 -8

ASE guidelines for M-mode measurements l Septum (SWT) l l LV cavity (LVID) Start of QRS Endocardium included in SWT and PWT Endocardium excluded from LVID LVM = 0. 8{1. 04[ (SWT+LVID+PWT)3 - (LVID)3]} + 0. 6 g Posterior wall (PWT) Divide by body surface area to get LV mass index Devereux et al. Am J Cardiol 1986; 57: 450 -8

Area-length method for calculation of LV mass LVmass=1. 05[5/6(A 1 x. L 1)-5/6(A 2 x. L 2)] Divide by body surface area to get LV mass index Reichek et al. Circulation 1983; 67: 348 -52

Age-adjusted incidence/ 100 subjects 4 -year age-adjusted incidence of cardiovascular disease according to LVMI (g/m 2) Redrawn from Levy et al; NEJM 1990; 322: 1561 -6.

4 -year age-adjusted cardiovascular mortality Incidence of cardiovascular mortality according to presence or absence of LVH P<0. 001 P=ns Redrawn from Levy et al, NEJM 1990; 322: 1561 -6.

Echocardiographic LVH and prognosis Sheps and Frohlich. Hypertension 1997; 29: 560 -563.

Risks associated with LVM and geometry Cardiovascular events† % patients Total mortality* RWT LVMI (g/m 2) *P<0. 001, †P=0. 03 LVMI (g/m 2) Koren et al. Ann Int Med 1991; 114: 345 -352.

Mean % in LVMI Regression of LVH by drug treatment: meta-analysis of RCTs Between treatment P<0. 01 Schmieder et al. JAMA 1996; 275: 1507 -1513

% from baseline LVH regression: LIVE study * *P<0. 05 for LVMI Sheridan and Gosse 1998

Events/ 100 patient years Prognostic significance of Echo LVM regression † * *P=0. 04, †P=0. 0004 after adjustment for age. Verdecchia et al. Circulation 1998; 97: 48 -54

OR for CV events (2 years) Prognostic significance of ECG voltage changes: Framingham * * *P<0. 05 Levy et al. Circulation 1994; 90: 1786 -1793

Who to refer for echocardiography? l Patients with borderline BP: l l Patient with multiple risk factors: l l l LVH may influence decision to treat 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)