1,721,176 research outputs found
Pharmacological cardioversion of atrial fibrillation : current management and treatment options.
No full textAtrial fibrillation (AF) is the most common form of arrhythmia, carrying high social costs. It is usually first seen by general practitioners or in emergency departments. Despite the availability of consensus guidelines, considerable variations exist in treatment practice, especially outside specialised cardiological settings. Cardioversion to sinus rhythm aims to: (i) restore the atrial contribution to ventricular filling/output; (ii) regularise ventricular rate; and (iii) interrupt atrial remodelling. Cardioversion always requires careful assessment of potential proarrhythmic and thromboembolic risks, and this translates into the need to personalise treatment decisions. Among the many clinical variables that affect strategy selection, time from onset is crucial. In selected patients, pharmacological cardioversion of recent-onset AF can be a safely used, feasible and effective approach, even in internal medicine and emergency departments. In most cases of recent-onset AF, pharmacological cardioversion provides an important--and probably more cost effective--alternative to electrical cardioversion, which can then be employed as a second-line therapy for nonresponders. Class IC agents (flecainide or propafenone), which can be safely used in hospitalised patients with recent-onset AF without left ventricular dysfunction, can provide rapid conversion to sinus rhythm after either intravenous administration or oral loading. Although intravenous amiodarone requires longer conversion times, it is still the standard treatment for patients with heart failure. Ibutilide also provides good conversion rates and could be used for AF patients with left ventricular dysfunction (were it not for high costs). For long-lasting AF most pharmacological treatments have only limited efficacy and electrical cardioversion remains the gold standard in this setting. However, a widely used strategy involves pretreatment with amiodarone in the weeks before planned electrical cardioversion: this provides optimal prophylaxis and can sometimes even restore sinus rhythm. Dofetilide may also be capable of restoring sinus rhythm in up to 25-30% of patients and can be used in patients with heart failure. The potential risk of proarrhythmia increases the need for careful therapeutic decision making and management of pharmacological cardioversion. The results of recent trials (AFFIRM [Atrial Fibrillation Follow-up Investigation of Rhythm Management] and RACE [Rate Control versus Electrical Cardioversion for Persistent Atrial Fibrillation]) on rate versus rhythm control strategies in the long term have led to a generalised shift in interest towards rate control. Although carefully designed studies are required to better define the role of pharmacological rhythm control in specific AF settings, this alternative option remains a recommendable strategy for many patients, especially those in acute care
Left ventricular lead stabilization to retain cardiac resynchronization therapy at long term: When is it advisable?
No full textAimsLeft ventricular (LV) lead dislodgement occurs in about 10.6% of patients in the first 12 months after cardiac resynchronization therapy defibrillator implantation, and causes lack of clinical improvement, repeated surgery, and predisposes to infective complications and death. To understand the factors predictive of lead dislodgement, and to investigate whether bipolar LV lead stabilization can reduce the dislodgement rate and improve the clinical outcome.Methods and resultsPredisposing coronary vein anatomy was identified on a retrospective series of 218 patients implanted before August 2009. Lead stabilization guided by vein anatomy was prospectively tested on consecutive patients from October 2009 to December 2010. Among 84 patients, lead stabilization based on vein anatomy was recommended in 19 patients, of which 16 agreed and 3 refused. Two of these latter had lead dislodgement within 1 month, whereas none of the former had adverse events during 23.8 ± 3.1 months follow-up. Only 1 of 58 patients deemed at low risk had lead dislodgement. Seven patients required lead stabilization for severe phrenic stimulation issues that dictated lead placement at specific sites. Patients with stabilized LV leads were more likely to be cardiac resynchronization therapy (CRT) responders than the others: 19 of 26 (73%) vs. 34 of 58 (59%, P= NS), and had a significantly higher proportion of super-responders: 12 of 26 (46%) vs. 12 of 58 (21%, P< 0.005).ConclusionCoronary vein anatomy may assist decision making about the need for LV lead stabilization, and the choice of tools during the implanting procedure to ensure effective CRT delivery at long term. © The Author 2013
New left ventricular active fixation lead: The experience of lead extraction
Full text linkAbstractLeft ventricular active fixation lead is fundamental for targeted pacing site. The challenge is the extraction but in our experience Attain® Stability™ was removed without any problem. As usual the lead can cause a thrombosis of the coronary vein but we performed a venoplasty in order to place again a lead in the target site and maintain the CRT response
Asymptomatic lone atrial fibrillation - how can we detect the arrhythmia?
No full textAtrial fibrillation (AF) may occur in the absence of identifiable causes, co-morbidities or structural cardiac disease (lone AF). Silent AF is common and patients may have a completely asymptomatic arrhythmia or may experience both symptomatic and asymptomatic AF episodes. It has been estimated that among patients with recognized AF, one third has no appreciable symptoms. In contemporary clinical practice, AF remains largely underdiagnosed and 25% of patients with AF-associated cardioembolic stroke have not been previously diagnosed with AF. The strategies for AF screening include opportunistic and systematic screening. Several methods for AF detection are nowadays available: from very simple (pulse palpation) to more advanced technologies proposed for ambulatory external monitoring of variable time duration. In patients previously implanted with cardiac electrical devices with an atrial lead, according to current clinical indications, the ability to continuously detect AF and to monitor its evolution is magnified, and AF burden can be precisely measured and monitored along with time. Similar information on AF burden can be also obtained by implantation of subcutaneous cardiac monitors that rely on the analysis of consecutive RR intervals for the diagnosis of AF. The prognosis is generally favorable for patients presenting with lone AF, but adverse outcomes, including stroke and thromboembolic events may occur at long term, in association with aging, or the development of underlying heart disease, or progression from paroxysmal to permanent AF. In this respect, the role of new technologies and diagnostic tools for AF detection and monitoring should be fully defined
BLOCK HF: How far does it extend indications for cardiac resynchronization therapy?
No full textThe Biventricular versus Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block (BLOCK HF) trial, published in April 2013 [Curtis AB, Worley SJ, Adamson PB, et al; Biventricular versus Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block (BLOCK HF) Trial Investigators. Biventricular pacing for atrioventricular block and systolic dysfunction. N Engl J Med 2013; 368:1585-1593], explored whether cardiac resynchronization therapy (CRT) was superior to conventional pacing in patients with conventional indications for pacing, left ventricular dysfunction and NYHA (New York Heart Association) class I-III. The trial took 8 years and a source of concern is selection bias, because participating centers had an average of two patients enrolled per center, per year. Both the internal and external validity of the trial merit some comments. BLOCK HF showed a relatively low treatment effect of CRT as compared with other CRT trials. As a matter of fact, the absolute risk reduction for death or hospitalization because of heart failure was 4.8%, in a relatively long follow-up, with a number needed to treat (NNT) of 21, much higher than the NNT of other CRT trials. We estimate that at least one third of patients in BLOCK HF could meet current indications for CRT. Moreover, the study did not consider the additional risks and costs of CRT versus conventional pacing, both having important implications for cost-effectiveness estimates. For these and other reasons, uncertainties arise as to how far BLOCK HF extends current recommendations for CRT and how much it should be implemented in daily clinical practice
Atrial Fibrillation in Patients with Cardiac Resynchronization Therapy: Clinical Management and Outcome
No full textAtrial fibrillation (AF) and heart failure (HF) are two emerging epidemics in the cardiovascular field and are strictly inter-related since may directly predispose to each other. Cardiac resynchronization therapy (CRT) has emerged as an important therapeutic option for selected HF patients with LV dysfunction and ventricular dyssynchrony. However almost all RCTs demonstrated the CRT effectiveness in patients in sinus rhythm (SR), including permanent AF among the exclusion criteria. In patients with paroxysmal or persistent AF strategies for rhythm control can be applied, but usually with limited efficacy. Furthermore, rhythm control strategy did not result superior to rate-control in patients with heart failure. AF ablation in HF patients is usually performed only in selected centres. In patients with permanent or long-standing AF and a CRT device the option of AVN ablation offers the advantage of allowing >95% biventricular pacing. AF implies a harmful increase in thromboembolic risk. Detection of AF in patients treated with a CRT device is enhanced by device diagnostic capabilities, that allow detection of episodes of atrial tachyarrythmias, including silent AF. In these cases decision making on appropriate antithrombotic prophy/laxis has to consider clinical risk stratification, usually applying CHADS2 and CHA2DS2VASc scores. In summary, in order to maximise outcome, AF in patients with CRT prompts the need to appropriately decide on antithromboembolic prophylaxis (according to risk stratifications), as well as on rate and/or rhythm control strategies, with the aim to allow constant biventricular pacing. In this perspective, AVN ablation has an important role since by inducing pace-maker dependency guarantees continuous biventricular pacing
Cardiac resynchronization therapy: The conundrum of predicting response in the individual patient
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