Management of atrial arrhythmias identified by cardiac devices.

Implantable cardiac devices have shown that atrial fibrillation (AF) is more frequent than previously assumed, with subclinical, asymptomatic, self-limiting manifestations called atrial high-rate events (AHREs) or subclinical AF. The clinical significance and correct therapeutic management of these episodes of subclinical AF is less well defined than in the case of clinically manifest AF. Two important randomized studies on the topic have recently been published, NOAH-AFNET 6 and ARTESIA, which, however, have not definitively clarified the topic. In patients with AHRE or subclinical AF, the average thrombo-embolic risk is lower than that in patients with clinically manifest AF and is ∼1%. For this reason, in these patients, the possibility that the benefit of anticoagulant therapy is overshadowed by the risk of bleeding is very high. Therefore, while waiting for new tools that allow a better stratification of low-risk patients, we must rely on individual clinical evaluation and overcome the qualitative dichotomy (AHRE yes vs. AHRE no), preferring instead an approach that is as quantitative as possible and takes into account the number of episodes, their duration, and the patient's CHADSVASC score, before deciding, in each individual case, whether or not to use anticoagulant therapy.

Dilemmas in cardiology: when to recanalize a chronic total occlusion.

The decision whether or not to recanalize a chronic total occlusion (CTO) of a coronary artery is truly a dilemma for the cardiologist. The procedure is in fact complex, with a non-negligible rate of complications and with a probability of success lower than that of non-obstructive lesions. The analysis of the data available in the literature, with the significant discrepancy between the results of the randomized studies and the observational studies, does not currently allow conclusive statements on the role of the percutaneous coronary interventions in CTO. It is therefore essential to incorporate clinical, anatomical and procedural elements into the decision-making algorithm. While awaiting new randomized clinical trials of greater dimensions and better methodology, a careful selection of patients is certainly essential, limiting the procedure to those who are symptomatic or who have a high ischaemic burden and excluding those who have no evidence of vitality, without which it is not legitimate to expect any benefit from the intervention. Finally, the presence of the collateral circulation does not in itself appear to be an element that should have a significant decision-making role.

When Brugada syndrome is at risk of sudden death: clinical and anatomical aspects.

The current prognostic stratification of asymptomatic patients with Brugada syndrome is suboptimal. The so-called 'Brugada burden' concept is certainly emerging: the more extensive are the electrocardiographic alterations of the syndrome in space (peripheral as well as precordial derivations) and in time (persistence in the follow-up of electrocardiographic alterations), the greater the probability of arrhythmic events. Numerous clinical and electrocardiographic markers have been considered risk factors, but none of them alone is able to guide the choice of whether or not to implant a defibrillator, the only therapy so far proved effective in preventing SD (sudden death) in these patients. The prognostic value of the electrophysiology study also gradually decreased over time. Therapeutic decisions must therefore be taken, at the moment, considering a large number of variables, possibly included in risk scores to be validated prospectively and in large series. Magnetic resonance and the study of electro-anatomical alterations of the right ventricular outflow tract will most likely improve our prognostic stratification capacity in the future.

The wireless pacemaker is on again; from electro-stimulation to synchronization.

Leadless stimulation of the right ventricle is now a reality, especially in patients with very specific indications and clinical characteristics, even in the absence of randomized studies to support its use. The reduction of device costs and the refinement of atrioventricular synchronization algorithms will sanction its greater diffusion in the future. The possibility of using leadless technology also for resynchronization therapy, on the other hand, is currently a promising option but, pending randomized studies with robust case histories and adequate follow-ups, it should still be considered as a niche therapy, to be limited to centres highly specialized and in patients in whom conventional resynchronization has been impossible or ineffective.

Knots to untie: anticoagulant and antiarrhythmic therapy after ablation for atrial fibrillation.

The continuation or otherwise of anticoagulant and antiarrhythmic therapy after ablation of atrial fibrillation (AF) is one of the main aspects still to be defined in the electrophysiological field. The currently available data do not allow the assumption of certain positions due to the lack of randomized studies on the subject. With regard to anticoagulant therapy, however, the suggestion of the guidelines to assess more the risk profile than the result of the ablation and consequently to prescribe anticoagulant treatment to all patients with CHADSVASc ≥2 seems acceptable. Its use in the first two or three months after the procedure appears reasonable; however, keeping in mind that the objective of this strategy is limited to the prevention of early recurrences only. More prolonged use of antiarrhythmics seems to be more promising, but further data are necessary before it can be recommended routinely. The ablation of AF is a therapy that is widely spreading and its use is continuously growing. Since it is a recently introduced method, not everything is still clear about it. The continuation or not of anticoagulant and antiarrhythmic therapy after ablation for AF is one of the main aspects yet to be defined.

Implant and long-term evaluation of atrial signal amplification in a single-lead ICD.

BACKGROUND: In patients without clinical indications for pacing the use of a single-lead implantable cardioverter defibrillator (ICD) implementing atrial sensing capability with proper signal amplification management may represent a useful therapeutic option, combining the positive features of both single and dual-chamber devices. The aim of the study was to evaluate the atrial signal amplification and its long-term stability in a single-lead ICD system adding atrial sensing to a standard single-chamber ICD. METHODS: P-wave amplitudes were collected and compared at implant both with a conventional external device ("unfiltered" P wave) and telemetrically with the implanted ICD ("filtered" P wave). Filtered/unfiltered P-wave ratio (amplification factor, AmF) was evaluated at implant and during follow-up. RESULTS: In 43 enrolled patients (38 men, age 64 ± 16 years), the mean filtered P wave at implant was significantly higher than the unfiltered P wave (3.85 ± 0.81 mV vs 2.0 ± 1.49 mV; P < 10(-11) ), with a mean AmF value of 2.77 ± 1.62. In seven patients with atrial fibrillation at implant, the AmF was higher (4.62 ± 1.94) than in patients in sinus rhythm (2.41 ± 1.30; P < 0.001). A significant linear correlation was found between the inverse of P wave and the AmF (R = 0.82, P < 0.00001). In 25 patients followed for 384 ± 244 days, atrial undersensing was never documented and AmF did not change from implant (3.19 ± 1.82; P = 0.24), also in different body position and breathing conditions. CONCLUSIONS: The single-lead ICD system evaluated reliably amplified P-wave amplitudes by a factor of about three, maintaining this performance during the observed follow-up.

Optical coherence tomography guided in-stent thrombus removal in patients with acute coronary syndromes.

The persistence of thrombus inside stent struts is a frequent event in patients with acute coronary syndromes (ACS) undergoing percutaneous coronary intervention (PCI), and this phenomenon might be associated with an increased risk of stent thrombosis. We sought to quantify by means of optical coherence tomography (OCT) the presence of in-stent thrombus after achievement of an optimal angiographic result in patients with ACS undergoing PCI. In addition, we evaluated the feasibility and safety of an OCT-guided strategy of in-stent thrombus removal. Eighty consecutive patients with ACS undergoing PCI were treated with two different strategies equally divided into two groups: angio-guided PCI, and OCT-guided PCI, in which additional OCT-driven in-stent balloon dilatation was adopted to reduce thrombus encroachment of the lumen. Overall in-stent thrombus area was 4.3 % with a maximal thrombus encroachment of 16.7 %. In the OCT-guided group, use of high pressure intra-stent dilatation led to a significant increase in stented area (9.6 ± 2.4 vs. 9.1 ± 2.49 mm(2), p = 0.002) and lumen area (9.2 ± 2.4 vs. 8.7 ± 2.3 mm(2), p < 0.001) and also significantly decreased in-stent thrombus area in absolute (0.35 ± 0.29 vs. 0.42 ± 0.30 mm(2), p = 0.001) and relative terms (3.58 ± 3.25 vs. 4.53 ± 3.01 %, p = 0.001). Values of TIMI flow, frame count and blush grade, as well as clinical outcomes were not detrimentally affected by such additional dilatations. The use of additional OCT-driven in-stent balloon dilatations is feasible, safe and might be effective in the treatment of in-stent thrombus for patients with ACS.

Detection of very early stent healing after primary angioplasty: an optical coherence tomographic observational study of chromium cobaltum and first-generation drug-eluting stents. The DETECTIVE study.

BACKGROUND: Lack of stent coverage appears to be associated with stent thrombosis, a problem of particular concern in patients with ST elevation myocardial infarction (STEMI). METHODS: The DETECTIVE European Multicenter Registry was set up to address the early modality of stent healing in the setting of STEMI. The Registry compared, with an early optical coherence tomography (OCT) evaluation performed at 3-7 days, the patterns of coverage and apposition of the first generation of drug-eluting stents (DESs) and cobalt chromium non-drug-eluting stents (CCSs) that were deployed in culprit lesions and in non-culprit segments. The Registry included only patients with a multi-vessel disease to allow, at 3-7 days from the first angioplasty, a deferred OCT examination and a staged intervention in another vessel. RESULTS: 28 stented lesions (15 patients) eventually entered the final OCT assessment. 13 stents were first-generation DESs, while the remaining 15 were CCSs. 18 stents (64%) were deployed at culprit STEMI lesions, and the remaining 10 (36%) were deployed at non-culprit sites. The distribution of clinical and procedural variables in DES and CCS as well as in culprit and non-culprit sites was not different. In total, 27,019 struts were analysed in 28 stents. The percentage of stent uncoverage in the overall analysis was 11.7%, while the percentage of malapposition and that of struts covered with thrombus were 4.8% and 2.2%, respectively. A low percentage of strut uncoverage was found in all the four studied subgroups: DES 12.8%, CCS 10.9%, stents deployed in culprit lesions 13.2% and stents deployed in non-culprit lesions 8.7%. CONCLUSIONS: In conclusion, our data show that in patients with STEMI, a very high percentage of stent struts is covered by an early thin rim of tissue within 7 days after stent positioning. The present data bring new insights in the mechanism and timing of strut coverage.