Different types of fibrosis and gap junction remodeling result in different fibrillation patterns and different mechanisms for sustaining VF

Meandering path of rotor activity / trajectory of phase singularities

"Most cases of ventricular fibrillation after cardiac pacing in acute myocardial infarction occur during manipulation of the temporary pacing electrode into the right ventricle, particularly after inferior or right ventricular myocardial infarction."

Current leakage from pacemaker caused very high electrical stimuli to be delivered, resulting in VF

Pacemaker induced VF caused by ICD, which then also terminated the VF

"The presence of right ventricular infarctlon seems to be a contributing mechanism involved in the induction of ventricular fibrillation during temporary pacing for bradyarrhythmia complicating acute myo- cardial infarction."

The probability of a pace- maker beat falling into a vulnerable period is further increased when two pacemakers are im- planted.

precipitation of ventricular fibrillation by
a stimulus from a cardiac pacemaker, although with surgical atrioventricular block and im- an interesting theoretic possibility, has never planted cardiac pacemakers. Intravenous iso- been reported clinically.

"S-L-S sequences are an important onset pattern for VT/VF"

"Cells with spontaneous impulse generation may be silenced when tightly coupled to surrounding myocardial cells, having membrane potentials that are more negative. The strong electrical coupling may clamp the membrane potential of the pacemaker cell to such a negative value that pacemaker activity is suppressed."

"Clamping of the pacemaker cells can be reduced or prevented by uncoupling them from the surrounding nonpacemaker cells. This can be achieved by decreasing connexin expression and/or increasing collagen deposition, which also tends to separate the cells electrically."

"Fibrosis may also play a role in arrhythmias based on abnormal impulse initiation such as automaticity and triggered activity."

"Studies with rotigaptide that enhances gap junction conductance and con- duction velocity have shown that the increase in cell-to-cell coupling does not affect the refractory period"

"Ventricular tachycardia (VT) was defined as a run of four or more consecutive premature ventricular beats (including torsades de pointes) and ventricular fibrillation (VF) as when it was unable to distinguish individual QRS complex or to measure the beating rate."

"Monomorphic ventricular tachycardia demonstrates a stable QRS morphology from beat to beat while polymorphic ventricular tachycardia has changing or multiform QRS variance from beat to beat.[1] Torsades de pointes is a polymorphic ventricular tachycardia that occurs in the setting of a long QT interval and appears as waxing and waxing QRS amplitude on ECG.[1]"

"Nerve remodeling as a result of MI is known to be an important genesis of life-threatening arrhythmias. It is hypothesized that neural modulation might serve as a therapeutic option of malignant arrhythmias"

"injected 50μg aconitine directly into the LVmuscle at a lateral LV site"

Wall motion assessed by echo is a good indicator of infarction size

"a form of VT in which there are multiple ventricular foci with the resultant QRS complex varying in amplitude, axis, and duration. The most common cause of PVT is myocardial ischaemia/infarction"

"Torsades de pointes (TdP) is a specific form of PVT occurring in the context of QT prolongation — it has a characteristic morphology in which the QRS complexes “twist” around the isoelectric line."