Incidence, predictors, and impact on outcome of increased left ventricular latency in patients undergoing cardiac resynchronization therapy.

PURPOSE: Latency during left ventricle (LV) pacing has been suggested as a potential cause of ineffectual biventricular pacing. We assessed the incidence, predictors, and impact on outcome of increased LV latency in 274 patients undergoing cardiac resynchronization therapy (CRT). METHODS: On implantation, the latency interval was defined as the shortest stimulus-to-QRS onset interval in any lead of the 12-lead ECG. A stimulus-to-QRS onset interval ≥ 40 ms was used to define the presence of increased LV latency. RESULTS: Increased LV latency was observed in 55 patients (20%). On multivariate analysis, only ischemic etiology proved to be a predictor of increased LV latency. On 12-month echocardiographic evaluation, 68% patients showed a ≥ 15% decrease in LV end systolic volume (74% patients with increased LV latency, 67% patients without increased LV latency (p = 0.58). The presence of increased LV latency was not associated with a different clinical response to CRT. CONCLUSIONS: Increased LV latency occurred in almost 20% of patients undergoing CRT and was more frequent in patients with ischemic heart disease. The presence of increased LV latency does not seem to have an impact on echocardiographic or clinical response to CRT.

Hemodynamic Surveillance of Ventricular Pacing Effectiveness with the Transvalvular Impedance Sensor.

The Transvalvular Impedance (TVI) is derived between atrial and ventricular pacing electrodes. A sharp TVI increase in systole is an ejection marker, allowing the hemodynamic surveillance of ventricular stimulation effectiveness in pacemaker patients. At routine follow-up checks, the ventricular threshold test was managed by the stimulator with the supervision of a physician, who monitored the surface ECG. When the energy scan resulted in capture loss, the TVI system must detect the failure and increase the output voltage. A TVI signal suitable to this purpose was present in 85% of the tested patients. A total of 230 capture failures, induced in 115 patients in both supine and sitting upright positions, were all promptly recognized by real-time TVI analysis (100% sensitivity). The procedure was never interrupted by the physician, as the automatic energy regulation ensured full patient's safety. The pulse energy was then set at 4 times the threshold to test the alarm specificity during daily activity (sitting, standing up, and walking). The median prevalence of false alarms was 0.336%. The study shows that TVI-based ejection assessment is a valuable approach to the verification of pacing reliability and the autoregulation of ventricular stimulation energy.

Treatment of lone atrial fibrillation: a look at the past, a view of the present and a glance at the future.

Despite its proven efficacy, the Cox-Maze III procedure did not gain widespread acceptance for the treatment of lone atrial fibrillation (LAF) because of its complexity and technical difficulty. Surgical ablation for LAF can now be successfully performed utilizing minimally invasive techniques. This article provides an overview of the current state of the art in the surgical treatment of LAF. A brief review of pathophysiology, pharmacological treatment as well as catheter ablation is also provided. The most widely employed minimally invasive approach to LAF has been the video-assisted bilateral mini-thoracotomy or thoracoscopic pulmonary vein island creation and left atrial appendage removal or exclusion, usually with ganglionic plexi evaluation and destruction. Recently, a hybrid approach has been introduced, which combines a mono or bilateral epicardial approach with a percutaneous endocardial ablation in a single-step procedure to limit the shortcomings of both techniques. Suboptimal results of both catheter ablation and surgery suggest that success in the treatment of LAF will probably rely on a close collaboration between the surgeon and the electrophysiologist. Further studies are warranted to determine whether the hybrid approach is effective, especially in patients with long-standing persistent and persistent LAF.

Pharmacological management of atrial fibrillation: one, none, one hundred thousand.

atrial fibrillation (AF) is associated with a significant burden of morbidity and increased risk of mortality. Antiarrhythmic drug therapy remains a cornerstone to restore and maintain sinus rhythm for patients with paroxysmal and persistent AF based on current guidelines. However, conventional drugs have limited efficacy, present problematic risks of proarrhythmia and cause significant noncardiac organ toxicity. Thus, inadequacies in current therapies for atrial fibrillation have made new drug development crucial. New antiarrhythmic drugs and new anticoagulant agents have changed the current management of AF. This paper summarizes the available evidence regarding the efficacy of medications used for acute management of AF, rhythm and ventricular rate control, and stroke prevention in patients with atrial fibrillation and focuses on the current pharmacological agents.

A randomized comparison of amiodarone and class IC antiarrhythmic drugs to treat atrial fibrillation in patients paced for sinus node disease: the Prevention Investigation and Treatment: A Group for Observation and Research on Atrial arrhythmias (PITAGORA) trial.

BACKGROUND: Rhythm control is an important goal in the treatment of recurrent atrial tachyarrhythmias (AT). The PITAGORA study was a randomized trial in patients paced for sinus node disease (SND), designed to test the noninferiority of class IC antiarrhythmic drugs (AADs) to amiodarone in terms of a primary end point composed of death, permanent AT, cardiovascular hospitalization, atrial cardioversion, or AAD change. METHODS: Randomization was stratified to assign 2 patients to amiodarone and 2 patients to class IC AADs: propafenone or flecainide. One hundred seventy-six patients (46% men, 72 +/- 8 years) were enrolled. Device diagnostics continuously monitored AT recurrences and duration. RESULTS: In a mean follow-up of 20 +/- 9 months, the primary end point occurred in 23 (30.7%) of 75 class IC patients and in 28 (40.0%) of 70 amiodarone patients. The absolute difference in the end point incidence (-9.3%; 95% CI between 3.7% and -22.3%) confirmed the noninferiority of class IC to amiodarone (P = .007). Kaplan-Meier 1-year freedom from AT episodes >10 minutes, 1 day, and 7 days was 40%, 73%, and 91% for amiodarone and 28%, 78%, and 86% for class IC AADs (P = nonsignificant). CONCLUSIONS: In patients paced for SND and suffering from AT, class IC AADs proved not to be inferior to amiodarone in terms of the primary composite end point described or end points which were differently composed of mortality, efficacy, or AAD side effects. The AADs studied also showed similar results in terms of symptoms, quality of life, and freedom from AT recurrences.

[Hypothermia in the elderly: a shivering case]. / L'ipotermia nell'anziano: un caso da brividi.

Hypothermia is a medical emergency in patients with a body temperature lower than 35 degrees C (95 degrees F) due to prolonged exposure to ambient cold temperatures without appropriate protection. This condition has a 5-fold increased risk of death in the elderly. Usually, diagnosis is suggested by warning signs and symptoms like lethargy, weakness and loss of coordination, confusion and reduced respiratory or heart rate. We report the case of a 76-year-old woman who was referred to our center for symptomatic sinus bradycardia and with typical electrocardiographic abnormalities (Osborn wave) that suggested the diagnosis of severe hypothermia.

Design and rationale of a randomized study to compare amiodarone and Class IC anti-arrhythmic drugs in terms of atrial fibrillation treatment efficacy in patients paced for sinus node disease: the PITAGORA trial.

AIMS: Many sinus node disease (SND) patients suffer from atrial fibrillation (AF). Anti-arrhythmic drugs (AADs) are the therapeutic mainstay for AF prophylaxis. The PITAGORA trial has a multicentre, prospective, randomized, single blind design to compare amiodarone with Class IC AADs in patients who have an AF history and are paced for SND. METHODS AND RESULTS: Starting from January 2001, 176 patients received a Medtronic AT500 pacemaker. AADs were randomly assigned with a 3 : 2 ratio between Class III and Class IC. Randomization was stratified in order to assign two patients to amiodarone and one patient to sotalol every three Class III AAD patients. After a 5-month observational period, Ramp or Burst+ ATP therapies were enabled in a randomized way, maintained for 4 months, and then crossed over. Total follow-up period is 21 months. The primary long-term objective is to show the non-inferiority of IC AADs compared with amiodarone in terms of time to first occurrence of a composite endpoint (death, atrial cardioversion, hospitalizations due to AF or heart failure, or change of AADs). Data will be analysed on an intention-to-treat basis. The primary short-term objective is to compare Ramp vs. Burst+ efficacy in terminating atrial tachyarrhythmias treated by the device. Secondary endpoints are major clinical events, medication toxicity, symptoms, AF burden, and quality-of-life. CONCLUSION: Given the high morbidity and healthcare costs associated with AF, new therapeutic strategies are needed. The results of the PITAGORA trial may help in guiding AADs therapy and ATP programming in SND patients suffering from AF.

[Atrioventricular nodal reentrant tachycardia with 2:1 anterograde block]. / Tachicardia reciprocante nodale con blocco 2:1 della conduzione anterograda.

We describe the case of a patient who presented with narrow QRS tachycardia at a rate of 100 b/min. The R-R intervals were constant, and negative P waves were evident in the inferior leads, midway between two ventricular complexes. A few minutes later, the tachycardia rate suddenly increased to 190 b/min, and the electrocardiographic pattern became typical of atrioventricular nodal reentrant tachycardia. Intravenous verapamil succeeded in restoring sinus rhythm. These data suggested an atrioventricular nodal reentrant tachycardia that at the beginning was associated with a 2:1 anterograde block.

[Persistent left superior vena cava and absence of right superior vena cava]. / Persistenza della vena cava superiore sinistra ed assenza della vena cava superiore destra.

Persistence of left superior vena cava is a rare finding. The combination of persistent left superior vena cava and absent right superior vena cava with no other congenital cardiovascular abnormalities has been exceptionally reported. We describe a case of persistent left superior vena cava and absent right superior vena cava observed during pacemaker implantation and confirmed by transthoracic contrast echocardiography.