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[18] [20] Since its first discovery, there have been many definitions of pacemaker syndrome, and the understanding of the cause of pacemaker syndrome is still under investigation. In a general sense, pacemaker syndrome can be defined as the symptoms associated with right ventricular pacing relieved with the return of A-V and V-V synchrony. [17]
This form of ventricular tachycardia occurs relatively infrequently, but if seen is suggestive of an underlying diagnosis of CPVT or the related condition Andersen-Tawil syndrome. [ 8 ] [ 9 ] These ventricular arrhythmias in some cases terminate by themselves, causing a blackout from which the person then recovers.
Ventricular escape beats occur when the rate of electrical discharge reaching the ventricles (normally initiated by the heart's sinoatrial node (SA node), transmitted to the atrioventricular node (AV node), and then further transmitted to the ventricles) falls below the base rate determined by the rate of Phase 4 spontaneous depolarisation of ventricular pacemaker cells. [1]
The physiological pacemaker of the heart is the sinoatrial node. [3] If the sinoatrial node is rendered dysfunctional, the AV node may act as the pacemaker. [4] If both of these fail, the ventricles begin to act as the dominant pacemaker in the heart. [1] The ventricles acting as their own pacemaker gives rise to an idioventricular rhythm.
Since pacemaker correction of the third-degree block requires full-time pacing of the ventricles, a potential side effect is pacemaker syndrome, and may necessitate the use of a biventricular pacemaker, which has an additional 3rd lead placed in a vein in the left ventricle, providing more coordinated pacing of both ventricles. [citation needed]
Causes of pacemaker failure include lead related failure, unit malfunction, problems at the insertion site, failures related to exposure to high voltage electricity or high intensity microwaves, and a miscellaneous category (one patient had ventricular tachycardia when using his electric razor and another patient had persistent pacing of the ...
Junctional rhythm is seen equally in men and women, and can be seen intermittently in young children and athletes, especially during sleep. It occurs commonly in patients with sinus node dysfunction. 1/600 cardiology patients over the age of 65 have sinus node dysfunction.
Ventricular tachycardia (V-tach or VT) is a cardiovascular disorder in which fast heart rate occurs in the ventricles of the heart. [3] Although a few seconds of VT may not result in permanent problems, longer periods are dangerous; and multiple episodes over a short period of time are referred to as an electrical storm.