Efectos de los cambios bruscos en la longitud del ciclo en la refractariedad del sistema de His-Purkinje en el hombre
Circulation
|January 1, 1983
Resumen
Los cambios bruscos en la longitud del ciclo auricular tienen un impacto significativo en el sistema His-Purkinje.
Área de la Ciencia:
- Electrofisiología y electrofisiología.
- Conducción cardíaca La conducción cardíaca es la conducción cardíaca.
- Mecanismos de las arritmias.
Sus antecedentes:
- La fibrilación auricular con frecuencia implica cambios abruptos en la longitud del ciclo auricular.
- El impacto de estas variaciones de la longitud del ciclo en el sistema de His-Purkinje (HPS) durante la conducción ventricular aberrante (VAb) no se entiende bien.
Objetivo del estudio:
- Investigar los efectos de los cambios bruscos en la longitud del ciclo auricular en el período refractario relativo (PRR) del sistema His-Purkinje (HPS).
- Para determinar cómo estos cambios influyen en la aparición de conducción ventricular aberrante (VAb).
Principales métodos:
- Evaluó el RRP del HPS en 12 pacientes con VAb durante el ritmo sinusal.
- Se utilizaron tres métodos: longitud constante del ciclo auricular (método I), cambios bruscos en la longitud del ciclo (método IIA: ciclos anteriores más largos, método IIB: ciclos anteriores más cortos) y una longitud constante del ciclo derivada del método II (método III).
Principales resultados:
- El método IIA (ciclos anteriores más largos) acortó el RRP-HPS en 8/12 pacientes, a pesar de un intervalo HH anterior más largo.
- Método IIB (ciclos anteriores más cortos) prolongó el RRP-HPS en 10/12 pacientes, y VAb se produjo sólo en esta condición en 2 pacientes.
- El Método III confirmó que los cambios bruscos en la longitud del ciclo, no solo la longitud del ciclo final, influyeron en la refractariedad de HPS y VAb.
Conclusiones:
- Las alteraciones bruscas en la longitud del ciclo auricular modifican de manera impredecible las propiedades funcionales del sistema His-Purkinje.
- Estos hallazgos sugieren que los cambios dinámicos en el ritmo auricular juegan un papel crucial en el desarrollo de la conducción ventricular aberrante durante la fibrilación auricular.
Videos de Conceptos Relacionados
01:13The Cardiac Cycle
The heart beats rhythmically in a sequence called the cardiac cycle—a rapid coordination of contraction (systole) and relaxation (diastole).
The Process
Electrical signals—sent from the sinoatrial (SA) node in the right atrial wall to the atrioventricular (AV) node between the right atrium and right ventricle—cause both atria to simultaneously contract. When the signal reaches the AV node, it pauses for approximately a tenth of a second, allowing the atria to contract and empty blood into the...
The Process
Electrical signals—sent from the sinoatrial (SA) node in the right atrial wall to the atrioventricular (AV) node between the right atrium and right ventricle—cause both atria to simultaneously contract. When the signal reaches the AV node, it pauses for approximately a tenth of a second, allowing the atria to contract and empty blood into the...
00:56Doppler Effect - I
The Doppler effect and Doppler shift were named after the Austrian physicist and mathematician Christian Johann Doppler in 1842, who conducted experiments with both moving sources and moving observers. Consider an observer standing on a street corner, observing an ambulance with a siren sound passing by at a constant speed. The observer experiences two characteristic changes in the sound of the siren. Initially, the sound increases in loudness as the ambulance approaches and decreases in...
01:19Electrophysiology of Normal Cardiac Rhythm
The normal cardiac rhythm is a synchronized electrical activity that facilitates the regular and coordinated contraction of the heart muscle. This process is essential for efficient blood circulation throughout the body. The fundamental elements involved in establishing and maintaining this rhythm include the unique electrical properties of cardiac muscle cells, the sinoatrial (SA) node's pacemaker function, the specialized conducting system, and the ionic mechanisms underlying each phase of...
01:28Mechanism of Cardiac Arrhythmias
Arrhythmias are irregular heart rhythms occurring when the heart's electrical impulses become abnormal. These disturbances can lead to various symptoms, depending on their severity and the underlying cause. Some common factors contributing to arrhythmias include hypoxia, ischemia, electrolyte imbalances, excessive catecholamine exposure, drug toxicity, and muscle overstretching. Arrhythmias can be classified into two main types based on the rate and site of origin of abnormal heart rhythms.
01:29Disturbances in Heart Rhythm
Arrhythmia or dysrhythmia refers to an abnormal heart rhythm caused by a defect in the heart's conduction system. It can cause the heart to beat irregularly, too quickly, or too slowly, leading to symptoms like chest pain, shortness of breath, and fainting. Factors such as stress, caffeine, alcohol, nicotine, cocaine, certain drugs, congenital defects, diseases, and electrolyte abnormalities can trigger arrhythmias.
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
01:29Dysrhythmias III: Characteristics of Dysrhythmias
Dysrhythmias, also known as arrhythmias, are irregular heart rhythms that result from abnormal electrical activity in the heart, affecting its ability to circulate blood efficiently. Tachyarrhythmias, a subset of dysrhythmias, are characterized by abnormally fast heart rates exceeding 100 beats per minute. Here are some types of tachyarrhythmias with their distinct ECG features:Sinus Tachycardia:Sinus tachycardia presents a regular heart rhythm with an increased rate of 101-180 beats per minute.