Systemic Hypertension

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Hypertensive heart disease is characterized by cardiac hypertrophy in response to increased cardiac afterload. This results in systolic and diastolic dysfunction as well as other structural abnormalities. These in turn manifests clinically as arrhythmias and symptomatic heart failure.[1] Echocardiography can demonstrate many of the effects of hypertension on cardiac function and structure.

Left Ventricular Hypertrophy

Left ventricular hypertrophy (LVH) is recognised as an independent predictor of morbidity and mortality. [2] [3] [4] The prevalence in hypertensive patients ranges from 36% to 41%.[5] LVH is essentially an increase in left ventricular (LV) mass. Methods to measure LV mass include Devereux’s Formula[6] and the Area Length Method.[7]

Inter-ventricular septal thickness and posterior wall thickness as well as the end-diastolic diameter can be measured using m-mode or 2D echocardiography. Devereux’s formula can then be used to estimate left ventricular mass:

LV mass(g) = 0.80 [1.04 {(PWT+LVID+SWT)3 - LVID3}] + 0.6

The Area Length Method can be used for both 2D and 3D echocardiography to estimate left ventricular mass:

LV mass(g) =1.05 X {5/6 (AEpi X LEpi) - (AEndo X LEndo)}

Indexing for body size by dividing LV mass by body surface area should be carried out for both methods.

Relative wall thickness (RWT) allows further classification of LV mass[8] [9]increase as either concentric hypertrophy (RWT >0.42) or eccentric hypertrophy (RWT ≤0.42):


Estimation of left ventricular mass by m-mode echocardiography Parasternal long and short axis views demonstrating severe left ventricular hypertrophy in a young man presenting with secondary hypertension

Diastolic Dysfunction

Hypertension can lead to diastolic dysfunction which can occur in the presence or absence of LVH. Diastolic dysfunction leads to elevated filling pressures.[10] There is no single measure of diastolic dysfunction. The different techniques need to be considered together to make an overall integrated assessment.

Pulsed-wave doppler assessment of transmitral flow should form the basis of assessment. From this peak early diastolic filling velocity (E) and peak late diastolic filling velocity (A), can be obtained as well as E:A ratio. Other important information available from this technique is the E wave deceleration time and the isovolumetric relaxation time.[11]

E wave deceleration time reflects LV compliance. In early diastolic dysfunction it increases. However, as progression of diastolic dysfunction occurs and filling pressures rise there is a decrease in the deceleration time. Isovolumetric relaxation time (IVRT) is the time from closure of the aortic valve to opening of the mitral valve. It is measured from a modified apical 4 chamber view which includes the outflow tract and aortic valve. A pulsed- wave doppler signal that simultaneously demonstrates aortic outflow and mitral inflow should be obtained. IVRT is the time interval between the two signals. It is prolonged in early diastolic dysfunction but like the E wave deceleration time becomes shorter as disease progresses.

Tissue Doppler myocardial imaging is the next step and is carried out at the ventricular basal wall at or within 1 cm of the mitral valve leaflet insertion point. Signals should be recorded from lateral and septal walls. This allows assessment of peak early diastolic myocardial velocity (e’) and peak late diastolic myocardial velocity (a’). The E/e’ ratio can then also be calculated from which an estimation of filling pressure can be made.[12]

Left atrial (LA) filling can also be assessed using pulsed-wave doppler interrogation of pulmonary venous flow. This should be looked at in conjunction with the other parameters of diastolic function. Peak systolic pulmonary vein flow velocity (S), peak diastolic pulmonary vein flow velocity (D), peak pulmonary vein atrial reversal velocity (AR) and AR duration (ARdur) can be obtained.

Diastolic dysfunction is classified into stages using the various echocardiographic parameters.

  1. Stage I - Impaired relaxation
  2. Stage II - Pseudo-normalisation
  3. Stage III - Restrictive which can be reversible or fixed

In any assessment of diastolic function the volume status of the patient must be taken into consideration as it influences the findings. Heart rate and rhythm also have an impact. Age is important - it is normal to see some degree of diastolic dysfunction in older patients. A valsalva manoeuvre should be used in order to distinguish the different stages.

Mitral inflow demonstrating E:A ratio of 0.8 with prolonged E wave deceleration of 257 msec in keeping with stage I diastolic dysfunction
Mitral inflow demonstrating E:A ratio of 1.3 and prolonged E wave deceleration time of 218 msec. For tissure doppler see next image.
Tissue doppler related to previous image demonstrating reduced e' to a' ratio in keeping with stage II diastolic dysfunction
Mitral inflow demonstrating E:A ratio of 1.8 and E wave deceleration time of 92 msec in keeping with stage III diastolic dysfunction

Left Atrial Size

As LV pressure rises so too will LA pressure to maintain diastolic filling of the LV. This increases wall tension and leads to chamber dilatation. LA size can therefore be considered a chronic reflection of filling pressures. LA size can be measured by diameter from the parasternal long axis view or alternatively by area or volume from apical views. However, indexed LA volume has been demonstrated to be a more sensitive marker of future cardiovascular events than LA diameter or area.[13] Left atrial volume has also been shown to be a marker for diastolic dysfunction severity.[14] Left atrial enlargement was correlated to blood pressure in the Framingham Heart study.[15] Left atrial volume has been shown to be increased even in those with mild hypertension.[16] Of course the size of the left atrium is of particular clinical relevance with respect to atrial fibrillation and stroke.

Enlarged left atrium by diameter measured from parasternal long axis view
Enlarged left atrium measured by area and volume measured from apical view

Speckle Tracking Echocardiography

Speckle tracking echocardiography (STE) is a means of assessing myocardial function which is largely angle independent and can be done offline after image acquisition. The myocardium scatters the sound waves which generate speckles specific for an area of myocardium. These speckles can be tracked from frame to frame and provide displacement information. Parameters of myocardial function such as velocity, strain and strain rate can then be derived.[17] STE allows the detection of subtle myocardial dysfunction and may be an appropriate tool to assess hypertensive patients who have subclinical disease but are at risk of progression to overt heart failure or even coronary artery disease.

Aortic Disease

Aortic dilatation is frequently seen in hypertensive patients. Studies have demonstrated prevalence rates above 10%.[18] [19] Hypertension is an important risk factor for aortic dissection.[20]

Dilated ascending aorta in an elderly lady with longstanding hypertension

Related Disorders

Finally to mention manifestations of disorders related to hypertension. Echocardiography may detect regional wall motion abnormalities in keeping with coronary artery disease. Systolic function may be depressed as a result. Atrial fibrillation may cause further dilatation of the left atrium. Slow flow may result in increased echogenicity or ‘smoke’, or even a left atrial thrombus particularly in the left atrial appendage.


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