Adrenergic Nervous System Influences on the Induction of Ventricular Tachycardia

Abstract

Among patients preselected for exercise-induced ventricular tachycardia, almost half could be induced into ventricular tachycardia by isoproterenol infusion. Mental stress was a less powerful inducer of ventricular arrhythmias in this study group.

Cardiac Arrhythmias Triggered by Sudden and Dynamic Efforts

“…Several studies 6,19,21,22 have suggested that changes in adrenergic tone are involved in the genesis and maintenance of cardiac arrhythmias, including potentially life‐threatening arrhythmias, and that the use of beta‐blocking medication plays an important role as an anti‐arrhythmic 23 . However, our results showed that most arrhythmias observed during CPET occurred in the group already using beta‐blockers.…”

I Diretriz Latino-Americana para o Diagnóstico e Tratamento da Cardiopatia Chagásica

“…In addition, SVT can have multiple sites of origin, making the task of eliminating all circuits a challenge 201,207,213,229,230 . In general, the site of origin of well-tolerated recurring SVT can be identified and the SVT interrupted in 60%-80% of the patients, but rapid and poorly tolerated SVT are frequently induced in the final assessment of the procedure 201,213,[227][228][229] . During long-term follow-up, at least 50% of the patients undergoing conventional ablation have clinical relapse, justifying the maintenance of antiarrhythmic drugs or ICD implantation 230 .…”

“…Most arrhythmias and conduction disorders occur during the chronic phase, being direct consequences of the chronic fibrosing myocarditis triggered by T. cruzi 28,198 , with formation of scars and aneurysms 24,28,198 . Those myocardial scars, focal or scattered spread across the ventricles, contribute to the genesis of reentry ventricular arrhythmias [199][200][201] . In addition, the cardiac excito-conduction tissue is frequently damaged, leading to sinus node dysfunction and disorders of the atrioventricular and intraventricular conduction 28,198 .…”

“…Ventricular function assessment on ECHO allows therapeutic and prognostic guidance 198,201 . Chagasic patients with ventricular arrhythmias can have ventricular aneurysms as follows: in the left ventricle, 80%; in the right ventricle, 10%; and in both ventricles, 10%.…”

“…The SVT is the most common potentially fatal reentry arrhythmia in patients with CCC and segmentary contractile changes, even when the global systolic function is preserved 24,28,[198][199][200] . The arrhythmogenic substrate of that disease is complex, with LV subendocardial, transmural and epicardial scars, which can also affect the right ventricle 200,[201][202][203][204][205][206][207] . Because of that anatomical complexity, the subendocardium or subepicardium (approximately 55% of ventricular tachycardias), or both (transmural circuits), can participate in the reentry circuits of CCC, explaining the presence of episodes of SVT with multiple morphologies 200,201,207 .…”