M.G. Bongiorni

Performance and clinical comparison between left ventricular quadripolar and bipolar leads in CRT: observational research

AIM To evaluate Attain Performa (Medtronic, Dublin, Ireland) quadripolar lead performance in clinical practice and, secondarily, to compare its long term clinical outcomes vs bipolar leads for left ventricular (LV) pacing. METHODS AND RESULTS We retrospectively analyzed clinical, procedural and follow-up data of 215 patients implanted with a quadripolar lead. One hundred and twenty one patients implanted with bipolar lead were selected to compare long-term clinical outcomes. The quadripolar lead was implanted in the target vein in 196 patients (91%) without acute dislodgements. In 50% of patients the chosen final pacing configuration at implant would not have been available with bipolar leads. A dedicated quadripolar pacing vector was chosen more frequently when the LV tip location was apical than otherwise (65.6% vs 42.7%, p=0.003). After a median follow-up of 14 months, the LV pacing threshold was less than 2.5V at 0.4ms in 98 patients (90%) with a safety margin between phrenic nerve and LV pacing threshold >3V in 97 patients (89%). We observed a slight trend toward a lower risk of heart failure worsening and a lower incidence of ventricular arrhythmias and pulmonary congestion in patients implanted with quadripolar leads compared with the control group. CONCLUSION Quadripolar leads improve the management of phrenic nerve stimulation at no trade-off with pacing threshold and lead stability. Quadripolar leads seems to be associated with a lower incidence of VT/VF and pulmonary congestion, when compared with bipolar leads, but further investigations are necessary to confirm that this positive effect is associated with better LV reverse remodeling.

The role of aortic valve anatomy in determining the site of origin of ventricular ectopic beats: correlation between echocardiographic and electrophysiologic data

Purpose: In presence of premature ventricular complexes (PVCs) arising from both Ventricular Outflow Tracts (RVOT and LVOT) its often difficult to determine the origin before intracardiac mapping, due to smooth different ECG features for adiacent sites (posteroseptal RVOT, anteroseptal LVOT, Aortic Cusps). The aim of our study was to determine if the aortic valve anatomy as assessed by transthoracic echocardiography (TTE) is correlated with the origin site of the PVCs in patients with no evidence of Structural Heart Disease (SHD) and uncertain ECG features who undergo ablation with Radio-Frequency (RF) of monomorphic PVCs. Methods and materials: Thirty-one consecutive patients (mean age 52.5±18 yrs, 19 males) with no evidence of SHD who underwent RF ablation of PVCs were enrolled in our study. In all patients the 24 h Holter monitoring showed that at least 20% of the total heart beats was represented by monomorphic PVCs arising from RVOT or LVOT. Ablation was performed using electro-anatomic mapping and image-integration provided by intracardiac echo. The site of origin of the PVCs was determined according to the site of effective ablation. A complete standard TTE was performed before the ablation procedure, including an emphasized study of the aortic valve; aortic valve sclerosis (AVS) was defined by the presence of enhanced echogenicity/thickness (>2mm) of the aortic cuspids or the presence of focal calcifications. Results: The systolic left ventricular function expressed as ejection fraction (%) was normal in all patients (58.5±7.2). AVS was found in 11 pts, in 10 being associated with trivial valvular regurgitation. The ablation procedure was acutely successful in all patients. PVCs were originating from the LVOT in 12 pts (38%). All patients with PVCs originating from RVOT had normal aortic valve, instead AVS was present in 92% of patients with PVCs from LVOT and all 3 patients with PVCs from the Aortic Cusps. Conclusions: The presence of the aortic valve sclerosis assessed by transthoracic echocardiography was correlated with the LVOT origin of the premature ventricular complexes and it could help the preoperative management of the patients without structural heart disease who undergo RF ablation of monomorphic PVCs in presence of ambiguous ECG features.

Sleep Apnea: New Insights

Sleep apnea is the most common disorder of breathing during sleep. It is defined as repeated episodes of obstructive apnea and hypopnea during sleep, together with daytime sleepiness or altered cardiopulmonary function [1]. There are three syndromes of upper airway closure during sleep: obstructive sleep apnea (OSA), obstructive sleep hypopnea, and upper airway resistance. These three syndromes share two features: excessive daytime sleepiness and arousal associated with increased ventilatory effort in response to upper airway closure. The specific sites of narrowing or closure and upper airway dysfunction are influenced by the underlying neuromuscular tone, upper airway muscle synchrony, and the stage of sleep. Sleep apnea may be classified as two major forms: obstructive sleep apnea and central sleep apnea (CSA). Heart failure (HF) affects about 5 million people in the USA [2], and the largest epidemiologic studies in patients with HF found rates of prevalence of OSA of 37% and 11% respectively [3, 4]. Thus, OSA and CSA have a heavy impact on the health of these patients and on public health resources.

How to Detect and Manage Pacemaker/ICD Failure and Infections

Device therapy involving pacemakers for bradyarrhythmias and implantable cardioverter defibrillators (ICDs) for tachyarrhythmias has undergone a surprising evolution. System failure and infection, however, are still possible complications. In contrast to the relative frequency of lead failure, either as a result of implantation error or of deterioration of the lead materials, primary malfunction of the pulse generator is rare. The key to diagnosing device failure lies in meticulous assessment of the integrity of the leads and an understanding of the timing cycles of the specific device, which is facilitated by access to bidirectional telemetry. Infection is another complication of implanted devices; it is reported to occur in 0–19% of patients with pacemakers [1, 2] and in 2%–7% of patients with ICDs.

Management of Atrial Fibrillation Suppression in AF-HF Comorbidity Therapy (MASCOT) Trial

Inter- [1,2], intra- [3,4], and atrioventricular [51(AV) dyssynchrony are not new concepts, but only recently have attempts been made to correct these disorders in an effort to treat heart failure (HF). A series of trials [6] has addressed partial or comprehensive cardiac resynchronization in patients with severe HF and evidence of cardiac dyssynchrony. Cardiac resynchronization should improve left ventricular (LV) performance; several trials [7-10] have demonstrated improvement in many hemodynamic parameters (LV and aortic pressure, shortening of mitral diastolic regurgitation, synchronized LV and atrial systole, LV volume, reduced myocardial oxygen consumption) and clinical end-points (quality of life, peak oxygen uptake, functional capacity, reduced number of hospitalizations). The incidence of atrial fibrillation (AF) double every 10 years in adults: there are 2-3 new cases/1000 annually in the age group of 55-64 years and 35 new cases/1000 annually between the age of 85 and 94 years [11-13]. The Framingham study demonstrated that AF is an independent risk factor for mortality with a relative risk of 1.5 for men and 1.9 for women. In patients with HF, the prevalence of AF is directly related to NYHA class: AF is present in 10% of patients in NYHA class II and 40% of patients in NYHA classes III-IV. However, HF morbidity is highly influenced by the coexistence of AF, independently of functional class. Moreover, the presence of symptomatic or asymptomatic AF in patients with LV dysfunction is linked to a poor prognosis and is independently associated with a higher risk of death from all causes and from progressive pump failure [14,15]. The prevalence of AF in most trials [16-22] on HF is shown in Fig. 1.

Can Ventricular Resynchronization Reduce Atrial Fibrillation Recurrences

In recent years a new pacing therapy has been proposed for patients affected by heart failure (HF) in order to reduce inter- [1,2], intra- [3,4], and atrioventricular [5] (AV) dyssynchrony. Cardiac resynchronization therapy (CRT) has the goal of correcting these hemodynamic disorders, thus improving left ventricular (LV) performance. The benefits of CRT have been evaluated in a series of clinical trials [6-10].

Percutaneous Extraction of Infected Pacemaker/ICD Leads: What Are the Current Technological Advances and Results?

Transvenous removal of permanent pacing and implantable cardioverter-defibrillator (ICD) leads is today an effective and relatively safe technique; its use will probably spread in the future because of the increasing number of pacemaker- or ICD-related complications. Abandonment of functionless pacing leads is becoming relatively common because the performance of the leads decreases with the implant duration [1,2]. Infection is another complication of implanted devices; it is reported to occur in from 0% up to 19% of the patients [3,4]. Endocardial ICD leads seem to give rise to the same complications as pacing leads; in ICD patients lead malfunction may result in dangerously inappropriate therapy or none. Infections occurring after implantation of an ICD are reported at an incidence of 2%-7%. All these complications can be treated by percutaneous lead removal. The indications for the procedure have been codified [5, 6] and today’s techniques are effective. The success rate of transvenous removal in most reports is now more than 90%, with a low rate of serious, life-threatening complications. Despite these excellent results, however, efforts are still being made to improve both the techniques and the outcome of the procedures, in order to achieve better success rates and a lower incidence of complications.

Pacemaker/ICD Lead Infection: What Are the Main Intracardiac Echocardiographic Features?

The techniques of transvenous lead extraction have developed over the last ten years, allowing an high success rate [1–8]. Recently, recommendations, indications, facilities and training for extraction of chronically implanted transvenous pacing and defibrillator leads have been published from the North American Society of Pacing and Electrophysiology Lead Extraction Conference Faculty [9]. However, the researches in this field are continuously growing to make it as safe as possible.