Catálogo de publicaciones - libros

The decision to implant a pacemaker needs to be kept in the clinical context of a benign condition which frequently affects young patients. Thus, cardiac pacing should be limited as the last-resort choice to a very selected small proportion of patients affected by severe vasovagal syncope. How to select these patients still remains partly uncertain.

It may be said that CRT has a role in improving functional capacity over conventional right ventricular pacing in patients with left ventricular failure who require permanent ventricular stimulation and/or in those with an indication for AV nodal ablation. As for the great majority of patients with advanced heart failure and AF without conventional indications for permanent cardiac pacing — a wide and progressively expanding population in the “border zone” of current indications for CRT — no definite data are available. Some promising results from ablated patients show a favourable trend in major cardiac event reduction after CRT. More controlled clinical data are required to achieve definite conclusions about the indications for CRT in heart failure patients with AF.

Cardiac resynchronisation therapy (CRT) is a non-pharmacological treatment for patients with severe congestive heart failure (CHF) due to systolic dysfunction who also present an intraventricular conduction abnormality and a QRS duration greater than 120 ms [1]. CRT has been shown to improve functional status, quality of life, and exercise tolerance and to decrease hospitalisation frequency in these patients: recent results of the MUSTIC [2] and MIRACLE [3] trials are consistent in showing an improvement in NYHA class, quality of life scores, and distance covered during a 6-min walking test. A decrease in dynamic mitral regurgitation, increase in left ventricular ejection fraction, and reverse remodelling effect on the left ventricle has also been noted. The COMPANION study has recently demonstrated that CRT provides significantly better results regarding a combined endpoint of mortality and heart failure hospitalisation [4].

Consequently, CRT has been included in the current American Heart Association/American College of Cardiology/North American Society of Pacing and Electrophysiology guidelines for the implantation of permanent pacemakers as a therapeutic option for patients with systolic heart failure, NYHA class ≥ 3, QRS duration ≥ 130 ms, left ventricular end-diastolic diameter ≥ 55 mm and ejection fraction < 35% [5]. According to these criteria, between 13% and 35% of patients with heart failure would be eligible for CRT [6, 7]. However, a growing body of evidence seems to suggest that a larger proportion of heart failure patients could benefit of CRT. Some of the ‘new’ indications for CRT are discussed in this paper.

Platelets play a pivotal role in the development and progress of atherosclerotic vascular disease, as well as in the pathogenesis of its unstable clinical manifestations (e.g., unstable angina, non-ST elevation myocardial infarction (MI), ST elevation MI, and stroke) [1].

Therefore, antiplatelet therapy is an integral component in the treatment of patients with atherosclerotic cardiovascular disease, which represents the leading cause of death and disability worldwide.

Aspirin is the cornerstone of oral antiplatelet therapy and is effective for the prevention and treatment of cardiovascular events [2].

The availability and cost-effectiveness of aspirin have made it the most widely employed antiplatelet agent for the prevention and treatment of vascular disease.

Effective haemodynamic sensing would open the way to the autoregulation of a number of pacemaker functions, which could thus be integrated into a single control system. The TVI sensor can be proposed to play this crucial role, allowing the assessment of systolic and diastolic modifications in ventricular volume by means of conventional pacing leads.

Evidence-based large clinical trials have undoubtedly demonstrated the benefits of ICD in specific populations. Guidelines are intended only as a tool to aid in the decision whether to implant an ICD or CRT device. The responsibility of physicians is primarily towards their patients, but judicious use of health care resources is critical to be able to provide a fair share to all the patients in need of these devices.

Either ventricular or atrial arrhythmias or conduction disturbances can be observed during PCI. Some of them occur as a complication of the procedure, but many of the arrhythmias are related to reperfusion injury. The patient’s characteristics, the type of the procedure, the features of the target vessel and the type of the lesion play an important role in the occurrence of arrhythmias. The majority of the arrhythmias tend to revert spontaneously, but when necessary, special treatment must be given promptly.

It may be said that CRT has a role in improving functional capacity over conventional right ventricular pacing in patients with left ventricular failure who require permanent ventricular stimulation and/or in those with an indication for AV nodal ablation. As for the great majority of patients with advanced heart failure and AF without conventional indications for permanent cardiac pacing — a wide and progressively expanding population in the “border zone” of current indications for CRT — no definite data are available. Some promising results from ablated patients show a favourable trend in major cardiac event reduction after CRT. More controlled clinical data are required to achieve definite conclusions about the indications for CRT in heart failure patients with AF.

The MADIT II study and the SCD-HeFT studies suggest that the ICD reduces total mortality in patients with patients with LV dysfunction. However, the cost-effectiveness of this treatment makes it far from affordable. Better selection of patients that could benefit from an ICD might increase the cost-effectiveness and decrease the percentage of patients in whom an ICD will only produce inappropriate discharges and other undesirable effects. Subgroup analysis has demonstrated a progressive increase in effectiveness of the ICD as QRS duration increases. Little benefit was derived in patients with a QRS of less than 0.12 s, whereas if a QRS duration of 0.15 s was used as a cut-off, a marked reduction in SCD was observed, comparable to that in MUSTT and MADIT I. Similarly, in the SCD-HeFT trial the relative benefits of ICD therapy appeared greater in patients with NYHA class II heart failure, the group in which sudden death is expected to predominate. There seemed to be no benefit in patients with NYHA class III heart failure.

L’angiografia coronarica costituisce ancora oggi la metodica diagnostica di riferimento nello studio del circolo coronarico nativo e dei controlli degli interventi di rivascolarizzazione coronarica, sia chirurgica (confezionamento di bypass) che tramite procedure interventistiche (angioplastica percutanea-PTCA e ).