Relevance of echocardiographic evaluation of right ventricular function in patients undergoing cardiac resynchronization therapy.

AIMS: Right ventricular (RV) dysfunction is a marker of poor prognosis in heart failure (HF) patients. It is still unclear whether RV function might influence response to cardiac resynchronization therapy (CRT). METHODS: Forty-four consecutive patients with HF, large QRS, and either intraventricular or interventricular dyssynchrony underwent echocardiographic evaluation before, 1 month after, and 6 months after CRT. Response to CRT was considered in case of significant LV reverse remodeling, defined as the occurrence of LV end-systolic volume (LVESV) reduction > or =15% at 6 months. RESULTS: All echocardiographic indexes of baseline RV function and dimensions were significantly more impaired in nonresponders versus responders to CRT: tricuspid annular plane systolic excursion (TAPSE 15 +/- 4 mm vs 20 +/- 5 mm, P = 0.001), RV systolic pulmonary artery pressure (RVSP 39 +/- 14 mmHg vs 27 +/- 8 mmHg, P = 0.02), RV end-diastolic area (RVEDA 23 +/- 6 cm(2) vs 16 +/- 3 cm(2) P < 0.001), RV end-systolic area (RVESA 16 +/- 6 cm(2) vs 8 +/- 2 cm(2), P = 0.001), and RV fractional area change (30 +/- 12% vs 48 +/- 8%, P < 0.001). All the indexes of RV function significantly correlated with the percentage of LVESV reduction after CRT. Severe RV dysfunction was defined as TAPSE < or =14 mm and the population was stratified into two groups based on baseline TAPSE < or = or > 14 mm. As compared to those with high TAPSE (n = 30), patients with low TAPSE (n = 14) were less likely to show LV reverse remodeling after CRT (76% vs 14%, P < 0.001). CONCLUSIONS: Our study suggests that RV function significantly affects response to CRT. Poor LV reverse remodeling occurs after CRT in patients with HF having severe RV dysfunction at baseline.

Left ventricular pacing lead positioning in the target vein of the coronary sinus: description of a challenging case.

The optimal left ventricular pacing location for cardiac resynchronization therapy should be individualized according to the site of maximal mechanical delay. However, the presence of vein stenosis or kinking in coronary sinus (CS) anatomy could hamper lead implantation in the target vessel. We describe the case of a patient with dilated cardiomyopathy and a dual-chamber pacemaker referred for upgrading to a biventricular device owing to New York Heart Association III heart failure symptoms. Tissue Doppler analysis before implantation showed that the area of maximum activation delay was located in the posterolateral region of the left ventricle. Insertion of the lead into a posterolateral vein of the CS by means of the standard over-the-wire approach was unsuccessful due to the presence of a stenosis at the ostium of the vein. Lead placement in an anterior vein of the CS was unsatisfactory owing to a poor local delay from QRS onset. After balloon vein angioplasty, the pacing lead passed through the stenotic tract at the ostium of the target vein and was successfully positioned in the posterolateral region. Three months after pacemaker implantation, echocardiography showed an important reduction in the indexes of both inter- and intraventricular asynchrony and a significant left ventricular reverse remodeling.

Predictive value of programmed ventricular stimulation in patients with ischaemic cardiomyopathy: implications for the selection of candidates for an implantable defibrillator.

AIMS: The present study assessed the role of programmed ventricular stimulation (PVS) in risk stratification of patients with ischaemic cardiomyopathy (ICM), candidates for implantable cardioverter-defibrillator (ICD). METHODS AND RESULTS: Consecutive patients with ICM and LVEF < or = 40% (n = 106, age 61 +/- 7 years, LVEF 27 +/- 7%) underwent PVS. This was considered positive in case of inducibility of monomorphic ventricular tachycardia (VT) with < or =3 extrastimuli; polymorphic VT, ventricular fibrillation (VF), and fast monomorphic VT (CL < or = 230 ms) with < or =2 extrastimuli. Primary end-point was the combination of arrhythmic death and VF requiring ICD shock. Forty-nine patients (46%) were inducible at PVS; 74 (70%) were implanted with ICD. During a 24-month follow-up, the primary end-point occurred more frequently in positive PVS patients among the overall population, among patients with LVEF < or = 30% (n = 80) and among patients with an ICD. The negative predictive value of PVS was 96% in each group. In the overall population, both PVS (HR 7.32, 95% CI 1.6-32) and LVEF (HR 4.59, 95% CI 1.6-13) predicted the primary end-point. CONCLUSION: PVS may still have a role in predicting the arrhythmic risk in patients with ICM. A negative PVS identifies a subgroup with a very low risk of arrhythmic events even in patients with LVEF < or = 30%.

Fast-slow and slow-slow form of atrioventricular nodal reentrant tachycardia sustained by the same reentrant circuit: a case report.

It has been suggested that a reentrant circuit confined to the posterior extensions of the atrioventricular node underlies both fast-slow and slow-slow types of atrioventricular nodal reentrant tachycardia (AVNRT). According to this hypothesis the fast-slow reentrant circuit would be formed by two slow pathways, located in the rightward and leftward posterior extension of the atrioventricular node. Thus, the fast pathway would act as a bystander with respect to the reentrant circuit. We describe the case of a 40-year-old woman with several episodes of palpitations unresponsive to antiarrhythmic drugs. The ECG during symptoms showed a narrow QRS tachycardia with a long ventriculo-atrial interval and a negative P wave in the inferior leads. Electrophysiological study showed the inducibility of a slow-slow AVNRT which rapidly shifted to a fast-slow AVNRT without any change in the duration of the tachycardia cycle. Our observation is in agreement with the hypothesis that the fast-slow reentrant circuit consists of two slow pathways with the fast pathway acting as a bystander.

Periodic conduction and 2:1 block from the left atrium to the pulmonary vein during radiofrequency ablation.

Paroxysmal atrial fibrillation is often initiated by foci in the pulmonary veins (PVs); the junction between the PVs and the left atrium (LA) has become the target of radiofrequency (RF) ablation performed to isolate the PVs. Ectopic atrial beats originating from the PVs propagate to the LA with a characteristically long conduction time, often with a conduction delay or block within the PV or at the PV-LA junction. However, details about the conduction properties within the PVs and across the PV-LA junction are still scanty. We report a unique case of LA-PV decremental conduction caused by RF applications. New insights into the electroanatomical characteristics of the PV-LA junction are provided. The present report demonstrates, for the first time in humans, that decremental conduction may be related to the progressive damage of the conducting myocardial bundle due to RF energy applications.