Fusion beat in patients with heart failure treated with left ventricular pacing: may ECG morphology relate to mechanical synchrony? A pilot study.

BACKGROUND: Electrical fusion between left ventricular pacing and spontaneous right ventricular activation is considered the key to resynchronisation in sinus rhythm patients treated with single-site left ventricular pacing. AIM: Use of QRS morphology to optimize device programming in patients with heart failure (HF), sinus rhythm (SR), left bundle branch block (LBBB), treated with single-site left ventricular pacing. METHODS AND RESULTS: We defined the "fusion band" (FB) as the range of AV intervals within which surface ECG showed an intermediate morphology between the native LBBB and the fully paced right bundle branch block patterns.Twenty-four patients were enrolled. Echo-derived parameters were collected in the FB and compared with the basal LBBB condition. Velocity time integral and ejection time did not improve significantly. Diastolic filling time, ejection fraction and myocardial performance index showed a statistically significant improvement in the FB. Interventricular delay and mitral regurgitation progressively and significantly decreased as AV delay shortened in the FB. The tissue Doppler asynchrony index (Ts-SD-12-ejection) showed a non significant decreasing trend in the FB. The indications provided by the tested parameters were mostly concordant in that part of the FB corresponding to the shortest AV intervals. CONCLUSION: Using ECG criteria based on the FB may constitute an attractive option for a safe, simple and rapid optimization of resynchronization therapy in patients with HF, SR and LBBB.

The fusion band in V1: a simple ECG guide to optimal resynchronization? An echocardiographic case report.

BACKGROUND: Patients with left bundle branch block have a preserved right bundle branch conduction and the efficacy of left ventricular pacing could be explained with the fusion between artificial pulse delivered in the left lateral wall and the spontaneous right ventricular activation. Moreover, the efficacy of left ventricular pacing could be enhanced with an optimal timing between the spontaneous right ventricular activation and the left ventricular pulse. CASE PRESENTATION: We evaluated a patient (male, 47 yrs) with surgically corrected mitral regurgitation, sinus rhythm and left bundle branch block, heart failure (NYHA class III) despite medical therapy and low ejection fraction (25%): he was implanted with a biventricular device. We programmed ventricular pacing only through the left ventricular lead. We defined what we called electrocardiographic "fusion band" as follow: programming OFF the stimulator, we recorded the native electrocardiogram and measured, through the device, the intrinsic atrioventricular interval. Then, atrioventricular interval was progressively shortened by steps of 20 ms down to 100 ms. Twelve leads electrocardiogram was recorded at each step. The fusion band is the range of AV intervals at which surface electrocardiogram (mainly in V1 lead) presents an intermediate morphology between the native left bundle branch block (upper limit of the band) and the fully paced right bundle branch block (lower limit). The patient underwent echocardiographic examination at each atrioventricular interval chosen inside the fusion band. The following parameters were evaluated: ejection fraction, diastolic filling time, E wave deceleration time, aortic velocity time integral and myocardial performance index. All the echocardiographic parameters showed an improvement inside the fusion band, with a "plateau" behaviour. As the fusion band in this patient ranged from an atrioventricular delay of 200 ms to an atrioventricular delay of 120 ms, we chose an intermediate atrioventricular delay of 160 ms, presuming that this might guarantee the persistence of fusion even during any possible physiological (autonomic, effort) atrioventricular conduction variation. CONCLUSION: In this heart failure patient with left bundle branch block, tailoring of the atrioventricular interval resynchronized myocardial contraction with left ventricular pacing alone, utilizing a sensed right atrial activity and the surface electrocardiographic pattern.

Successful treatment of electrical storm with oral quinidine in Brugada syndrome.

A patient implanted with a cardioverter-defibrillator for symptomatic Brugada syndrome was referred to our hospital 17 months later because of recurrent shocks due to ventricular fibrillation (VF). Isoprenaline was intravenously infused and prevented VF episodes, but VF recurred after every attempt of drug discontinuation. A total of 34 shocks were recorded over 25 days. Subsequently, we treated the patient with oral quinidine and the drug suppressed the electrical storm and prevented VF episodes during a follow-up period of 3 years. This case report, together with few others reported in the literature, suggests a role of oral quinidine in the treatment of electrical storm in Brugada syndrome.

Feasibility and safety of noninvasive pacemaker stress echocardiography with externally triggered stimulation.

The aim of this study was to assess the feasibility and safety of stress echocardiography by triggering an implanted pacemaker through an external stimulator. The implanted pacemaker was set in triggered mode with unipolar sensitivity of <2 mV. The external stimulator, connected to 2 skin electrodes, tracked the implanted pacemaker at increasing rates. Fifteen patients (mean age 65 +/- 8 years) with suspected coronary artery disease entered the study, and complete tests were performed in all patients. No adverse effects were reported. The method of externally triggered stimulation is feasible, safe, and allows a diagnosis in every patient with a pacemaker without additional cost.

Sexual activity with and without the use of sildenafil: risk of cardiovascular events in patients with heart disease.

The data in the literature on the relationship between sexual activity, with and without the use of sildenafil, and the occurrence of cardiovascular events (ventricular arrhythmias, nonfatal myocardial infarction, stroke and death) have been reviewed in patients with heart disease. To date, only patients with ischemic heart disease (IHD) have been investigated. The prevalence of premature ventricular beats during sexual intercourse is similar to that observed during other daily activities. Therefore, sexual activity does not seem to have a relevant arrhythmogenic effect. The incidence of sustained ventricular tachycardia during sexual intercourse in unknown. The relative risk of nonfatal myocardial infarction is 2.7 in males and 1.3 in females; however, the absolute risk appears extremely low and is similar in normal subjects and in patients with and without IHD. The risk appears to be restricted to the 2-hour time period after sexual intercourse. The incidence of stroke during sexual intercourse appears very low, but clear data are lacking. The incidence of death during sexual activity is unknown; the few available data suggest that it is very low. Extramarital sexual intercourse seems to increase the risk of death. The incidence of cardiovascular events after sildenafil administration has been investigated in placebo-controlled studies in patients with IHD. The incidence of nonfatal myocardial infarction, stroke and death did not significantly differ between sildenafil-treated and placebo-treated patients; therefore, sildenafil does not appear contraindicated in subjects with IHD. However, the drug should be administered with caution in patients with recent myocardial infarction or stroke, in those with active coronary ischemia and in patients with episodes of heart failure. The drug is absolutely contraindicated in patients using nitrates.

In industrialized nations, a low socioeconomic status represents an independent predictor of mortality in patients with acute myocardial infarction.

BACKGROUND: It has been widely demonstrated that in the general population a low socioeconomic status (SES) represents a risk factor for coronary heart disease (CHD). Both the incidence of and the mortality due to CHD are significantly higher in subjects with a low SES. Conventional risk factors only partly account for the social gradient in CHD. The aim of this study was to evaluate whether mortality was associated with SES in patients with acute myocardial infarction (AMI). METHODS: To this purpose the articles dealing with AMI and SES, having a prospective cohort design, total mortality or sudden death as primary endpoint and multivariate analysis as statistical approach, were analyzed. RESULTS: Among the patients hospitalized for AMI, a low SES was associated with more advanced disease, as shown by a significantly higher prevalence of heart failure and of recurrent ischemic events. The in-hospital treatment and prescriptions at discharge were similar among the various socioeconomic groups. The pre-hospitalization, in-hospital and long-term mortality were significantly higher in the most deprived subjects and a low SES represented an independent predictor (adjusted odds ratio ranging from 1.4 to 3.1). The few available data suggest the socioeconomic gradient as being a predictor even of sudden death. CONCLUSIONS: A low SES represents an independent predictor of mortality in patients with AMI. The current prognostic stratification of AMI patients is rather disappointing. In order to get a more precise prognostic stratification and to approach an adequate prophylaxis, a low SES should be utilized; however, the mechanisms mediating the adverse outcome of low socioeconomic groups should be further investigated.

Clinical spectrum of neurally mediated reflex syncopes.

AIMS: The clinical features of the various types of neurally mediated reflex syncope have not been systematically investigated and compared. We sought to assess and compare the clinical spectrum of neurally mediated reflex syncopes. METHODS AND RESULTS: Four hundred sixty-one patients with syncope were prospectively evaluated and 280 had neurally mediated reflex syncope. Each patient was interviewed using a standard questionnaire. A cause of syncope was assigned using standardized diagnostic criteria. Typical vasovagal syncope was diagnosed in 39 patients, situational syncope in 34, carotid sinus syncope in 34, tilt-induced syncope in 142 and complex neurally mediated syncope (positive response to both carotid sinus massage and tilt test) in 31. The clinical features of situational, carotid sinus, tilt-induced and complex neurally mediated syncope were very similar. By contrast, typical vasovagal syncope differed from other neurally mediated syncopes not only in terms of its precipitating factors (fear, strong emotion, etc.), which constituted predefined diagnostic criteria, but also in the variety of its clinical features (lower age and prevalence of organic heart disease, higher prevalence of prodromal symptoms, and of autonomic prodromes, longer duration of prodromes, higher prevalence of symptoms during the recovery phase and lower prevalence of trauma). CONCLUSION: The clinical spectrum of neurally mediated reflex syncopes demonstrates much overlap between them. However, when the afferent neural signals are localized in cortical sites, as in typical vasovagal syncope, symptoms are more frequent and of longer duration.