Ablação de Taquicardia Ventricular em Doentes Coronários: Para Além do Circuito [50] (original) (raw)
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Ablation of Polymorphic Ventricular Tachycardias in Patients with Structural Heart Disease
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Monomorphic ventricular premature beats (VPB) originating from the Purkinje network can induce polymorphic ventricular tachycardia (PMVT) and ventricular fibrillation (VF) storm. We hereby report the results of targeted ablation to treat PMVT/VF storms initiated by monomorphic VPB in seven patients with structural heart disease and left ventricular (LV)-dysfunction (n = 4 with coronary artery disease (CAD), n = 2 with chronic and remote myocarditis, n = 1 after aortic valve replacement).
Ablation of Ventricular Tachycardia in Patients with Structural Heart Disease
Pace-pacing and Clinical Electrophysiology, 2008
Catheter ablation is an important therapeutic option for controlling recurrent ventricular arrhythmias in patients with heart disease. Although implantable defibrillators are generally first line therapy in this patient population, a substantial number of patients require additional therapy with either antiarrhythmic drugs, ablation, or both. Studies of mapping and ablation have produced further insights into pathophysiologic mechanisms of these arrhythmias, which are now well characterized. The majority is due to reentry through regions of ventricular scar. Methods for identifying scar based on electrogram characteristics now allow arrhythmogenic areas to be targeted for ablation during stable sinus rhythm, such that ablation is often an option even when multiple and unstable ventricular tachycardia are present. Ablation failure can also be due to anatomical obstacles; however, methods for accessing the pericardial space for mapping and ablation and technological progress can be expected to further improve its efficacy.
Circulation. Arrhythmia and electrophysiology, 2016
The most common form of idiopathic Purkinje-related ventricular tachycardia (VT) is the reentrant type. We describe the clinical and electrophysiological characteristics of focal non-reentrant fascicular tachycardia. Among 530 idiopathic VT patients who were referred for ablation, we identified 15 (2.8%) with non-reentrant fascicular tachycardia (11 men, 45±21 years). Sinus rhythm ECG showed normal conduction intervals with a His-ventricular interval of 41±4 ms. All patients had monomorphic VT (cycle length: 337±88 ms) with a relatively narrow QRS (123±12 ms), and they did not respond to verapamil during the initial presentation. VT exhibited right bundle-branch block/superior axis configuration in 11 patients (73%) and inferior axis in 3 (20%). In 1 patient (7%), VT exhibited left bundle-branch block/superior axis configuration. During ablation, spontaneous VT occurred in 3 patients (20%) and nonentraintable VT or identical premature ventricular complex was induced in 9 (60%). A hi...
Journal of …, 1998
The possible contribution of localized conduction delay and abnormal action potentials to ventricular fibrillation (VF) was studied by applying an anisotropic cardiac computer model to clinical cases of the Brugada-type electrocardiogram (ECG), which shows right bundle branch block (RBBB), a normal QT interval, ST-segment elevation, and late r' in leads V I and V 2. The anisotropic heart model was composed of 50,000 discrete units with a spatial resolution of 1.5 mm and was mounted in a human torso model. The Iongitudinal/transverse conduction velocity ratio was 3:1. For the normal ECG, a conduction velocity of 0.75 m/s was required. In the abnormal area of the right anterior epicardial wall, the conduction velocity was set at 0.2 m/s, with decreasing action potential amplitude and 10% prolonged action potential duration. The ECG features of ST-segment elevation and Brugada-type right bundle branch block pattern were simulated. The action potential duration was able to change dynamically with coupling interval of stimulation, with a ratio of 9% for normal ventricu]ar muscle and 50% for Purkinje fibers. Five successive stimuli were applied to the left lateral epicardium 300 ms after the first sinus excitation, and sustained VF was induced with the transmural conduction delay at the right anterior ventricle as a block increasing the vulnerability. At the initiation of VE reentry circuits were shown around tee border zone of the right epicardium and were very heterogeneous around the conduction delayed area and septal area. In an area with the characteristics of nontransmural conduction delay, sustained VF was prevented, and the pattern of transient right bundle branch bIock appeared on the simulated ECG and body surface potential maps. The late r' wave was caiculated in the precordial leads and right anterior site on the body surface potential maps. These results suggest that increased multipolarity in the border zone between the Purkin]e fibers and delayed conduction area in the right ventricle might play an important role as a functional block for the persistence of VE