The electrocardiographic patterns recorded from seven patients with isorhythmic A-V dissociation fall into two distinct groups. In pattern I, the P wave fluctuates cyclically back and forth across the QRS complex. The mechanism responsible for this type of A-V synchronization represents a typical biologic feedback control system. The P-R interval is a determinant of stroke volume, which in turn influences the arterial blood pressure. The blood pressure has an inverse effect on the discharge frequency of the S-A node through the baroreceptor reflex. The S-A nodal frequency then affects the P-R interval, to close the feedback loop. In pattern II, the P wave is in a fairly constant position relative to the QRS complex. It is usually coincident with the QRS complex or appears on the ST segment or first half of the T wave. The mechanism producing synchronization in pattern II type of isorhythmic dissociation has not been established conclusively.
A comparison of the hemodynamic effects of ventricular and sequential A-V pacing in patients with heart block
The relationship between the timing of atrial systole and the useful work of the left ventricle in man
Radiofrequency ablation of a supraventricular tachycardia due to interatrial conduction from the recipient to donor atria in an orthotopic heart transplant recipient
Unusual atrial potentials in a cardiac transplant recipient. Possible synchronization between donor and recipient atria
Ventriculophasic arrhythmia and synchronization: clinical observations and study on an electrical analogue
Atrial and ventricular fetal heart rate patterns in isolated congenital complete heart block detected by magnetocardiography
Isorhythmic dissociation in a young flight candidate: cause for restriction, referral, or reassurance?
The effects of ageing and adrenergic challenge on electrocardiographic phenotypes in a murine model of long QT syndrome type 3
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