Hypertension & LVH

• LVH-Echo
  • Assessment
  • Example
  • LV Geometric Patterns
  • LV Geometric Patterns in the HOT Study
  • Impact on Prognosis
  • Impact of drugs on LVH

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• LVH-ECG
• Which ECG Criterion?
• Impact on Prognosis

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Hypertension and Left Ventricular Hypertrophy

Asssessed with Echocardiography

Left ventricular hypertrophy (LVH) or increased LV mass in patients with hypertension predicts increased risk of future cardiac events.

There are numerous different formulae for the diagnosis of LVH from the standard ECG. However, the ECG is relatively insensitive for the diagnosis of LVH.

Echocardiography is more sensitive for diagnosis of LVH. However, it is important to emphasise that this refers to criteria based on calculated left ventricular mass indexed for height or body surface area; and with different cut-off points used for men and women.

Those with relatively thick left ventricular walls (thick in relation the the size of the left ventricular end-diastolic dimension) are classified as having concentric left ventricular hypertrophy, and in a simplistic scheme, the remaining patients may be classified as having eccentric LVH.

Thus, one might identify four groups of patients, using this scheme:

• Concentric LV remodelling- those without LVH but with relatively thick walls.
• No LVH or concentric LV remodelling.
• Concentric LVH- those with LVH and with relatively thick walls.
• Eccentric LVH- those with LVH but without relatively thick walls.

One of the problems with incorporating echo assessment of LVH into routine practice relates to the difficulty in obtaining reproducible calculations of LV mass. If LV mass is assessed by this technique, it becomes important to measure wall thickness and LV size with M-mode Doppler on at least three occasions to improve accuracy.

Due to difficulties obtaining reproducible measurements, most would not recommend tailoring anti-hypertensive therapy based on serial assessments of LV mass. However, there may be a role for the single measurement of LV mass for the purposes of risk stratification. Other echo findings, such as assessment of diastolic function and left atrial size may also be useful in guiding patient management.

It is this difficulty with obtaining reproducible calculations of LV mass that seems to have resulted in failure to routinely use this technique but to simply rely on subjective assessments combined with absolute wall thickness measurements. This conventional approach which does not estimate LV mass disadvantages females and those of short stature the most by under-reporting left ventricular hypertrophy.

We should estimate LV mass more often in selected patients with hypertension, and not rely on simple measurements of wall thickness applying the same cut-off points for all patients regardless of height and gender.

Of note, is that guidelines do not recommend routine use of echocardiography in all hypertensive patients to assess for left ventricular hypertrophy, but recommend it as an option for some patients.

I suspect a single assessment for LVH with echocardiography may be valuable in some patients.

• Echo may help in confirming the need to initiate treatment for hypertension or emphasising the need to ensure good control of hypertension. This might particularly apply to patients that do not exceed the "treatment threshold" recommended by the NZ guidelines on prevention of cardiovascular disease. In other words, even though a particular patient may have a risk below the treatment threshold, we might decide that echo evidence of LVH should not be ignored and anti-hypertensive treatment started.
• There will be other patients in whom we may decide to try to ensure "optimal control of hypertension" rather than just try to reduce the calculated risk below 15% as recommended by the NZ guidelines.