What Is a Precordial Lead?

TOF is an abbreviation for tetralogy of fallot. TOF is a combined congenital cardiac vascular malformation, including pulmonary artery stenosis, ventricular septal defect, right aortic position (riding on the ventricular septum across the defect), Right ventricular hypertrophy and other four cases, the main ones are ventricular septal defect and pulmonary artery stenosis. This disease is the most common cyanotic congenital cardiovascular disease. Patients with only ventricular septal defect, pulmonary artery stenosis, and right ventricular hypertrophy without aortic stride are referred to as atypical tetralogy of Fallot.

TOF

(Farlow tetralogy)

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TOF is

(A) symptoms are mainly progressive from childhood

(A) X-ray inspection

The most common complication is cerebral thrombosis.

1.

The clinical manifestations of tetralogy of Fallot are more characteristic and generally not difficult to diagnose, but it needs to be distinguished from other congenital cardiovascular diseases with cyanosis.

(1) Pulmonary arterial stenosis with atrial septal defect accompanied by right-to-left shunt (Trilogy of Fallot). The disease appears later. The systolic murmur in the second intercostal space of the left margin of the sternum is louder and takes longer, and the second heart sound in the pulmonary valve area is reduced and split. On the X-ray film, the heart shadow increased significantly, and the main trunk arc of the pulmonary artery was prominent. The performance of right ventricular strain in ECG is more obvious. Examination of the right heart catheter, selective indicator dilution curve determination, or selective cardiovascular angiography revealed that the pulmonary artery stenosis was valvular and the right-to-left shunt level was in the atrium, and the diagnosis could be established.

(B) Eisenmenger syndrome. Ventricular septal defect, atrial septal defect, aortic-pulmonary septal defect, or arterial duct failure in patients with severe pulmonary hypertension, the left-to-right shunt is converted to right-to-left shunt, forming Eisenmenger syndrome. The cyanosis of this syndrome appears late; there are systolic jet sounds and systolic whistle-like murmurs in the pulmonary valve area; the second heart sound is hyperactive and can be split; whistle-like diastolic murmurs can be seen; X-ray examination shows that the main trunk arc of the pulmonary artery is prominent and The portal blood vessel shadow is large and the pulmonary field blood vessel shadow is small. Examination of the right heart catheter reveals significant pulmonary hypertension, which can be identified.

(3) Ebbstein deformity and tricuspid atresia. In Ebbstein's malformation, the septal and posterior leaflets of the tricuspid valve are moved down to the ventricle, the right atrium is enlarged, and the right ventricle is relatively small, often accompanied by atrial septal defects that cause right-to-left shunts. Four heart sounds can often be heard in the anterior region of the heart; X-rays show increased heart shadow, often spherical, and the right atrium can be very large; ECG shows right atrial hypertrophy and right bundle branch block; selective right atrial angiography shows increased right Atrial and malformed tricuspid valves can establish a diagnosis. When the tricuspid valve is blocked, the tricuspid valve is completely blocked, and the blood in the right atrium enters the left atrium through an unobstructed oval foramen or atrial septal defect, enters the left ventricle through the mitral valve, and then passes through a ventricular septal defect or an unoccluded arterial catheter to the pulmonary circulation. . X-ray examination showed that the right ventricle was not obvious and the lung field was clear. ECG showed left ventricular hypertrophy. Selective right atrial angiography can establish a diagnosis.

(D) Dislocation of large blood vessels. Pulmonary arteries originate from the left ventricle and complete aorta originate from the right ventricle, often accompanied by atrial or ventricular septal defects or open arterial ducts. The heart is often significantly enlarged. X-rays show pulmonary congestion. Selective right ventricular angiography can establish a diagnosis. In incomplete large vessel dislocations, the aorta and pulmonary arteries of patients with double-ventricular outlets from the right ventricle are emitted from the right ventricle, often accompanied by ventricular septal defects. X-ray films show significant increase in heart shadow, pulmonary congestion, and selective right ventricular angiography diagnosis. Differential diagnosis will be difficult if there is pulmonary stenosis at the same time.

(5) Arterial trunk is permanent. When the arterial trunk is permanent, there is only one set of semilunar valves that span the two ventricles. Both the pulmonary artery and the brachiocephalic artery originate from this arterial trunk, often accompanied by ventricular septal defects. In patients with tetralogy of Fallot, if the pulmonary artery is severely diseased, when the pulmonary artery and pulmonary valve atresia are formed, its performance is similar to that of the permanent arterial trunk, which is called pseudoarterial permanent. Pay attention to the identification of the two. For this, selective right ventricular angiography is helpful.

TOF: time-of-flight, the principle of time flight. The principle of time flight refers to various methods of measuring time of flight, more precisely the time it takes an object or particle or other waves such as sound waves or radio waves to travel a certain distance in a certain medium.

TOF: turn overfrequency. Catalytic term refers to the amount of conversion of the reaction substrate per mole of catalyst per unit time.