Pressure overload

Pressure overload of the right ventricle leads to right ventricular hypertrophy; right image.

Pressure overload refers to the pathological state of cardiac muscle in which it has to contract while experiencing an excessive afterload. Pressure overload may affect any of the four chambers of the heart, though the term is most commonly applied to one of the two ventricles. Chronic pressure overload leads to concentric hypertrophy of the cardiac muscle, which can in turn lead to heart failure, myocardial ischaemia or, in extreme cases, outflow obstruction.^[1]

Causes

Any obstruction to the outflow of one of the chambers of the heart can lead to pressure overload.

Left ventricular pressure overload

Right ventricular pressure overload

Signs and symptoms

A forceful apex beat indicates left ventricular pressure overload, while a right ventricular heave suggests right ventricular pressure overload. Other signs provide evidence for specific causes of pressure overload. Hypertension is diagnosed by sphygmomanometry. A narrow pulse pressure is a sign of aortic stenosis. The chest x-ray may show pulmonary hyperaemia in the case of pulmonary hypertension, and pulmonary oligaemia in pulmonary stenosis. Pulmonary hypertension is also associated with chronic lung disease. Coarctation of the aorta presents with a significant difference in blood pressure between the upper and lower limbs.

Treatment

Treatment will depend on the underlying cause. However, in general, symptomatic relief from pressure overload will not be achieved immediately, but will involve a delayed response following the atrophy of the hypertrophied heart muscle.

References

↑ Graham, T. P.; Lewis, B. W.; Jarmakani, M. M. (1970). "Left Heart Volume and Mass Quantification in Children with Left Ventricular Pressure Overload". Circulation 41: 203–12. doi:10.1161/01.cir.41.2.203.

Physiology of the cardiovascular system

Heart

Cardiac output	Cardiac cycle Cardiac output Heart rate Stroke volume Stroke volume End-diastolic volume End-systolic volume Afterload Preload Frank–Starling law of the heart Cardiac function curve Venous return curve Wiggers diagram Pressure volume diagram

Ultrasound	Fractional shortening = (End-diastolic dimension End-systolic dimension) / End-diastolic dimension Aortic valve area calculation Ejection fraction Cardiac index

Heart rate	Cardiac pacemaker Chronotropic (Heart rate) Dromotropic (Conduction velocity) Inotropic (Contractility) Bathmotropic (Excitability) Lusitropic (Relaxation)

Conduction	Conduction system Cardiac electrophysiology Action potential cardiac atrial ventricular Effective refractory period Pacemaker potential Electrocardiography P wave PR interval QRS complex QT interval ST segment T wave U wave Hexaxial reference system

Chamber pressure	Central venous Right atrial ventricular pulmonary artery wedge Left atrial ventricular Aortic

Other	Ventricular remodeling

Vascular system/
Hemodynamics

Blood flow	Compliance Vascular resistance Pulse Perfusion

Blood pressure	Pulse pressure Systolic Diastolic Mean arterial pressure Jugular venous pressure Portal venous pressure

Regulation of BP	Baroreflex Kinin–kallikrein system Renin–angiotensin system Vasoconstrictors Vasodilators Autoregulation Myogenic mechanism Tubuloglomerular feedback Cerebral autoregulation Paraganglia Aortic body Carotid body Glomus cell

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