We present an update on clinical and electrophysiological criteria used for the differential diagnosis of regular supraventricular tachycardias. Although several electrocardiographic clues may assist ...in the differential diagnosis, this is usually accomplished at electrophysiology study, and most often, the differential diagnosis is between atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia due to a concealed accessory pathway, and atrial tachycardia. Atrial and ventricular pacing maneuvers during sinus rhythm or tachycardia have been used with various success rates. In clinical practice, these techniques cannot be applied to all cases, and multiple criteria must be used for the differential diagnosis of narrow-complex tachycardias with atypical characteristics.
Nonsustained Ventricular Tachycardia Katritsis, Demosthenes G., MD, PhD; Zareba, Wojciech, MD, PhD; Camm, A. John, MD
Journal of the American College of Cardiology,
11/2012, Letnik:
60, Številka:
20
Journal Article
Recenzirano
Odprti dostop
Nonsustained ventricular tachycardia (NSVT) has been recorded in a wide range of conditions, from apparently healthy individuals to patients with significant heart disease. In the absence of heart ...disease, the prognostic significance of NSVT is debatable. When detected during exercise, and especially at recovery, NSVT indicates increased cardiovascular mortality within the next decades. In trained athletes, NSVT is considered benign when suppressed by exercise. In patients with non–ST-segment elevation acute coronary syndrome, NSVT occurring beyond 48 h after admission indicates an increased risk of cardiac and sudden death, especially when associated with myocardial ischemia. In acute myocardial infarction, in-hospital NSVT has an adverse prognostic significance when detected beyond the first 13 to 24 h. In patients with prior myocardial infarction treated with reperfusion and beta-blockers, NSVT is not an independent predictor of long-term mortality when other covariates such as left ventricular ejection fraction are taken into account. In patients with hypertrophic cardiomyopathy, and most probably genetic channelopathies, NSVT carries prognostic significance, whereas its independent prognostic ability in ischemic heart failure and dilated cardiomyopathy has not been established. The management of patients with NSVT is aimed at treating the underlying heart disease.
There is now emerging evidence that AI may support diagnostics in electrophysiology by automating common clinical tasks or aiding complex tasks using deep neural networks that are superior to ...currently implemented computerised algorithms.4 Soon, AI simulations of the circuit of monomorphic ventricular tachycardia may be used to guide catheter ablation, or even stereotactic radioablation for a vast number of patients.5 Combining data obtained from several diagnostic modalities using AI might elucidate pathophysiological mechanisms of new, rare, or idiopathic cardiac diseases, aid the early detection or targeted treatment of cardiovascular diseases or allow for screening of disorders currently not associated with the ECG.4 Is all this the future or just wishful thinking? Rebecca Goldin, writing for the Genetic Literacy Project in response to President Obama’s 2013 announcement of a broad new research initiative to understand the human brain, provides perspective:7 “The human brain is estimated to have approximately 86 billion neurons (8.6 x 1010), each neuron with possibly tens of thousands of synaptic connections; these little conversation sites are where neurons exchange information. Personalized virtual-heart technology for guiding the ablation of infarct-related ventricular tachycardia.
The aim of this study was to investigate whether the combination of conventional pulmonary vein isolation (PVI) by circumferential antral ablation with ganglionated plexi (GP) modification in a ...single ablation procedure, yields higher success rates than PVI or GP ablation alone, in patients with paroxysmal atrial fibrillation (PAF).
Conventional PVI transects the major left atrial GP, and it is possible that autonomic denervation by inadvertent GP ablation plays a central role in the efficacy of PVI.
A total of 242 patients with symptomatic PAF were recruited and randomized as follows: 1) circumferential PVI (n = 78); 2) anatomic ablation of the main left atrial GP (n = 82); or 3) circumferential PVI followed by anatomic ablation of the main left atrial GP (n = 82). The primary endpoint was freedom from atrial fibrillation (AF) or other sustained atrial tachycardia (AT), verified by monthly visits, ambulatory electrocardiographic monitoring, and implantable loop recorders, during a 2-year follow-up period.
Freedom from AF or AT was achieved in 44 (56%), 39 (48%), and 61 (74%) patients in the PVI, GP, and PVI+GP groups, respectively (p = 0.004 by log-rank test). PVI+GP ablation strategy compared with PVI alone yielded a hazard ratio of 0.53 (95% confidence interval: 0.31 to 0.91; p = 0.022) for recurrence of AF or AT. Fluoroscopy duration was 16 ± 3 min, 20 ± 5 min, and 23 ± 5 min for PVI, GP, and PVI+GP groups, respectively (p < 0.001). Post-ablation atrial flutter did not differ between groups: 5.1% in PVI, 4.9% in GP, and 6.1% in PVI+GP. No serious adverse procedure-related events were encountered.
Addition of GP ablation to PVI confers a significantly higher success rate compared with either PVI or GP alone in patients with PAF.
Sequence of retrograde atrial activation is not a reliable criterion for the classification of atrioventricular nodal re-entrant tachycardia (AVNRT) into typical and atypical types. The conventional ...concept of a lower common pathway is not supported by current evidence and does not represent a reliable or reproducible criterion. The distinction between 'fast-slow' and 'slow-slow' forms is not unanimously defined, and probably of no practical significance. We suggest that AVNRT should be classified as typical or atypical according to the His-atrial interval or, when a His bundle electrogram is not reliably recorded, the ventriculo-atrial interval measured on the His bundle recording electrode.
Abstract
Aims
The exact circuit of atrioventricular nodal re-entrant tachycardia (AVNRT) remains elusive. To assess the location and dimensions of the AVNRT circuit.
Methods and results
Both typical ...and atypical AVNRT were induced at electrophysiology study of 14 patients. We calculated the activation time of the fast and slow pathways, and consequently, the length of the slow pathway, by assuming an average conduction velocity of 0.04 mm/ms in the nodal area. The distance between the compact atrioventricular node and the slow pathway ablating electrode was measured on three-dimensionally reconstructed fluoroscopic images obtained in diastole and systole. We also measured the length of the histologically discrete right inferior nodal extension in 31 human hearts. The length of the slow pathway was calculated to be 10.8 ± 1.3 mm (range 8.2–12.8 mm). The distance from the node to the ablating electrode was measured in five patients 17.0 ± 1.6 mm (range 14.9–19.2 mm) and was consistently longer than the estimated length of the slow pathway (P < 0.001). The length of the right nodal inferior extension in histologic specimens was 8.1 ± 2.3 mm (range 5.3–13.7 mm). There were no statistically significant differences between these values and the calculated slow pathway lengths.
Conclusion
Successful ablation affects the tachycardia circuit without necessarily abolishing slow conduction, probably by interrupting the circuit at the septal isthmus.
Graphical Abstract
Proposed model of the AVNRT circuit and site of successful ablation (RF lesions indicated by red arrow). The left inferior extension is derived from the atrioventricular canal myocardium and is low in connexin C43 expression, thus being capable of only slow conduction. The right inferior extension could either be slowly or rapidly conducting, since it incorporates both the primary ring and the atrioventricular canal myocardium, and is an area of higher C43 expression. CS, coronary sinus; FO, foramen ovale; LI, left inferior extension; RI, right inferior extension; S, superior ‘last’ input; TV, tricuspid valve. Figure modified from Katritsis.6
Immunohistochemistry studies suggest that the anatomic substrate of the slow pathway in atrioventricular nodal reentrant tachycardia (AVNRT) is the left inferior nodal extension. We hypothesized that ...slow pathway ablation from the left septum is an effective alternative to right-sided ablation.
We analyzed our databases of AVNRT in search of cases that had used slow pathway ablation from the left septum because of failure of right septal ablation, and then prospectively subjected consenting patients to a left septal-only procedure. Of 1342 patients subjected to right septal slow pathway ablation for AVNRT, 15 patients, 11 with typical and 4 with atypical AVNRT, had a left septal approach after unsuccessful right-sided ablation (R+L group). Eleven patients were subjected to a left septal-only approach for slow pathway ablation without a previous right septal attempt (L group). Fluoroscopy times in the R+L and L groups were 30.5 (21.0-44.0) and 20.0 (17.0-25.0) minutes, respectively (
=0.061), and radiofrequency current delivery times were 11.3 (5.0-19.1) and 10.0 (7.0-12.0) minutes, respectively (
=0.897). There was no need for additional ablation lesions at other anatomic sites in either group, and no cases of atrioventricular block were encountered. Recurrence rates of the arrhythmia for the R+L and L groups were 6.7% and 0%, respectively, in the 3 months after ablation (
=1.000).
Left septal ablation at the anatomic site of the left inferior nodal extension is an alternative for ablation of both typical and atypical AVNRT when ablation at the right posterior septum is ineffective.
Simple is Complicated Katritsis, Demosthenes G
Arrhythmia & electrophysiology review,
10/2021, Letnik:
10, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Theoretically, a mid-septal position should also be an optimum pacing site in the normal ventricle, and simple septal pacing appears to be a user-friendly, widely applicable solution, as Heckman et ...al. claim in this issue of the journal.4–6 This could be the answer to the quest not only for cardiac resynchronisation, but also for ‘physiological’ pacing, especially in young patients with congenital heart block who may need lifelong pacing on the left ventricle. The differences between selective and non-selective His bundle pacing and the potential caveats of a non-selective approach have been well addressed by the pioneers of the technique and are also discussed by Heckman et al.6 Further, although theoretically a mid-septal position should be the optimum site in the normal ventricle, no benefit over apical pacing has been shown in randomised studies, but there has been no long-term follow-up, especially in the paediatric population.4,5,7,8 Last but not least, the effectiveness of a septal approach for patients with extensive septal scars post-infarct is questionable if not unattainable. Demosthenes G Katritsis Editor-in-Chief, Arrhythmia & Electrophysiology Review Hygeia Hospital, Athens, Greece Johns Hopkins School of Medicine, Baltimore, MD, US Arnold A, Whinnett ZI, Vijayaraman P. His–Purkinje conduction system pacing: state of the art in 2020.
Selective ganglionated plexi (GP) ablation guided by high-frequency stimulation has been proposed for the treatment of paroxysmal atrial fibrillation (AF), but the efficacy of the method is not ...established.
This study sought to compare selective ablation of GP identified by high-frequency stimulation with extensive regional ablation targeting the anatomic areas of GP in patients with paroxysmal AF.
Eighty patients with paroxysmal AF (age 53 +/- 9 years) were randomized to undergo selective GP ablation or regional left atrial ablation at the anatomic sites of GP. For selective GP ablation (n = 40), ablation targets were the sites where vagal reflexes were evoked by high-frequency stimulation. Vagal reflexes were defined as prolongation of the R-R interval by >50% and a concomitant decrease in blood pressure (>20 mm Hg) during AF. The end point of the procedure was failure to reproduce vagal reflexes with repeated high-frequency stimulation. For anatomic ablation, lesions were delivered at the sites of GP clustering.
At 13.1 +/- 1.9 months, 42.5% of patients with selective GP and 77.5% of patients with anatomic ablation were free of symptomatic paroxysmal AF (PAF) (P = .02). Parasympathetic denervation was more prominent in patients with anatomic than selective GP ablation, and in patients free of AF compared to these with AF recurrence immediately after ablation, but this trend was abolished at 6 months.
Selective GP ablation directed by high-frequency stimulation does not eliminate paroxysmal AF in the majority of patients. An anatomic approach for regional ablation at the sites of GP confers better results.
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