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Heart sounds are the noises generated by the beating heart and the resultant flow of blood through it. Specifically, the sounds reflect the turbulence created when the heart valves snap shut. In cardiac auscultation, an examiner may use a stethoscope to listen for these unique and distinct sounds that provide important auditory data regarding the condition of the heart.
The mitral valve, also known as the bicuspid valve or left atrioventricular valve, is one of the four heart valves. It has two cusps or flaps and lies between the left atrium and the left ventricle of the heart. The heart valves are all one-way valves allowing blood flow in just one direction. The mitral valve and the tricuspid valve are known as the atrioventricular valves because they lie between the atria and the ventricles.
The systole is the part of the cardiac cycle during which some chambers of the heart muscle contract after refilling with blood. The term originates, via New Latin, from Ancient Greek συστολή (sustolē), from συστέλλειν, and is similar to the use of the English term to squeeze.
A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood received from an atrium towards the peripheral beds within the body and lungs. The atrium primes the pump.
The papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves via the chordae tendineae and contract to prevent inversion or prolapse of these valves on systole. The papillary muscles constitute about 10% of the total heart mass.
Afterload is the pressure that the heart must work against to eject blood during systole. Afterload is proportional to the average arterial pressure. As aortic and pulmonary pressures increase, the afterload increases on the left and right ventricles respectively. Afterload changes to adapt to the continually changing demands on an animal's cardiovascular system. Afterload is proportional to mean systolic blood pressure and is measured in millimeters of mercury.
A ventricular septal defect (VSD) is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart. The extent of the opening may vary from pin size to complete absence of the ventricular septum, creating one common ventricle. The ventricular septum consists of an inferior muscular and superior membranous portion and is extensively innervated with conducting cardiomyocytes.
Ebstein's anomaly is a congenital heart defect in which the septal and posterior leaflets of the tricuspid valve are displaced towards the apex of the right ventricle of the heart. It is classified as a critical congenital heart defect accounting for <1% of all congenital heart defects presenting in ≈1 per 200,000 live births. Ebstein anomaly is the congenital heart lesion most commonly associated with supraventricular tachycardia.
The Rastelli procedure is an open heart surgical procedure developed by Italian physician and cardiac surgery researcher, Giancarlo Rastelli in 1967 at the Mayo Clinic, Ajmer and involves using a pulmonary or aortic homograft conduit to relieve pulmonary obstruction in double outlet right ventricle with pulmonary stenosis.
In electrocardiography, the T wave represents the repolarization of the ventricles. The interval from the beginning of the QRS complex to the apex of the T wave is referred to as the absolute refractory period. The last half of the T wave is referred to as the relative refractory period or vulnerable period. The T wave contains more information than the QT interval. The T wave can be described by its symmetry, skewness, slope of ascending and descending limbs, amplitude and subintervals like the Tpeak–Tend interval.
The cardiac cycle is the performance of the human heart from the beginning of one heartbeat to the beginning of the next. It consists of two periods: one during which the heart muscle relaxes and refills with blood, called diastole, following a period of robust contraction and pumping of blood, called systole. After emptying, the heart immediately relaxes and expands to receive another influx of blood returning from the lungs and other systems of the body, before again contracting to pump blood to the lungs and those systems. A normally performing heart must be fully expanded before it can efficiently pump again. Assuming a healthy heart and a typical rate of 70 to 75 beats per minute, each cardiac cycle, or heartbeat, takes about 0.8 seconds to complete the cycle. There are two atrial and two ventricle chambers of the heart; they are paired as the left heart and the right heart—that is, the left atrium with the left ventricle, the right atrium with the right ventricle—and they work in concert to repeat the cardiac cycle continuously,. At the start of the cycle, during ventricular diastole–early, the heart relaxes and expands while receiving blood into both ventricles through both atria; then, near the end of ventricular diastole–late, the two atria begin to contract, and each atrium pumps blood into the ventricle below it. During ventricular systole the ventricles are contracting and vigorously pulsing two separated blood supplies from the heart—one to the lungs and one to all other body organs and systems—while the two atria are relaxed. This precise coordination ensures that blood is efficiently collected and circulated throughout the body.
Pulsus paradoxus, also paradoxic pulse or paradoxical pulse, is an abnormally large decrease in stroke volume, systolic blood pressure and pulse wave amplitude during inspiration. The normal fall in pressure is less than 10 mmHg. When the drop is more than 10 mmHg, it is referred to as pulsus paradoxus. Pulsus paradoxus is not related to pulse rate or heart rate, and it is not a paradoxical rise in systolic pressure. The normal variation of blood pressure during breathing/respiration is a decline in blood pressure during inhalation and an increase during exhalation. Pulsus paradoxus is a sign that is indicative of several conditions, including cardiac tamponade, chronic sleep apnea, croup, and obstructive lung disease.
The apex beat, also called the apical impulse, is the pulse felt at the point of maximum impulse (PMI), which is the point on the precordium farthest outwards (laterally) and downwards (inferiorly) from the sternum at which the cardiac impulse can be felt. The cardiac impulse is the vibration resulting from the heart rotating, moving forward, and striking against the chest wall during systole. The PMI is not the apex of the heart but is on the precordium not far from it. Another theory for the occurrence of the PMI is the early systolic contraction of the longitudinal fibers of the left ventricle located on the endocardial surface of this chamber. This period of the cardiac cycle is called isovolumic contraction. Because the contraction starts near the base of the left ventricle and spreads toward the apex most of the longitudinal fibers of the left ventricle have shortened before the apex. The rapidly increasing pressure developed by the shortening of these fibers causes the aortic valve to open and the apex to move outward causing the PMI. Anatomical dissection of the musculature of the apex reveals that muscle fibers are no longer longitudinal oriented but form a spiral mass of muscular tissues which may also have an effect on the ability of the apex to contract longitudinally. After the longitudinal fibers contract, the ejection of blood out of the left ventricle is accomplished by the torsional action of the circumferential muscle fibers of the left ventricle that are in the mid-portion of the ventricle and contract after the longitudinal fibers. During the longitudinal fiber contraction, the volume of the left ventricle has not changed keeping the apex in intimate contact with the chest wall allowing the ability to feel the apex move outward before the heart empties greater than 55% of its volume and the apex falling away from the chest wall.
Levo-Transposition of the great arteries is an acyanotic congenital heart defect in which the primary arteries are transposed, with the aorta anterior and to the left of the pulmonary artery; the morphological left and right ventricles with their corresponding atrioventricular valves are also transposed.
Double outlet right ventricle (DORV) is a form of congenital heart disease where both of the great arteries connect to the right ventricle (RV). In some cases it is found that this occurs on the left side of the heart rather than the right side.
A ventricular outflow tract is a portion of either the left ventricle or right ventricle of the heart through which blood passes in order to enter the great arteries.
Right ventricular hypertrophy (RVH) is a condition defined by an abnormal enlargement of the cardiac muscle surrounding the right ventricle. The right ventricle is one of the four chambers of the heart. It is located towards the lower-end of the heart and it receives blood from the right atrium and pumps blood into the lungs.
Crisscross heart is a type of congenital heart defect where the right atrium is closely associated with the left ventricle in space, and the left atrium is closely associated with the right ventricle.
The Senning procedure is an atrial switch heart operation performed to treat transposition of the great arteries. It is named after its inventor, the Swedish cardiac surgeon Åke Senning (1915–2000), also known for implanting the first permanent cardiac pacemaker in 1958.
Bernheim Syndrome is a presumed disorder whereby the right ventricle is severely compressed due to a shift in the ventricular septal wall of the heart leading to heart failure. It was first described by Hippolyte Bernheim in 1910. Today it is questioned whether or not Bernheim Syndrome is its own syndrome or a side effect of other cardiac conditions such as left ventricular heart failure whereby the left ventricle is substantially enlarged which encroaches on the space of the right ventricle.
References
- ↑ "Ventricular Inversion: Background, Pathophysiology, Etiology". eMedicine. 15 June 2021. Retrieved 31 October 2021.
