Long-term clinical and echocardiographic outcomes of Mitraclip therapy in patients nonresponders to cardiac resynchronization.

OBJECTIVES: This study deals with clinical and echocardiographic outcomes in cardiac resynchronization therapy (CRT) nonresponders patients undergoing Mitraclip procedure. BACKGROUND: Functional mitral regurgitation (FMR) occurs in approximately one-third of heart failure (HF) patients. Resynchronization therapy may correct FMR in patients with HF; however, significant FMR persists in 20-25% of CRT patients. METHODS: All patients included were previously treated with CRT for at least 6 months and remained classified as New York Heart Association (NYHA) functional class III or IV despite optimal medical therapy; the echocardiographic assessment showed lack of decrease of the left ventricular end-systolic volume (LVESV) of at least 10% and residual moderate-to-severe or severe FMR. Clinical and echocardiographic follow-up was scheduled at 1, 3, 6, and 12 months after Mitraclip implantation, and every 6 months thereafter. RESULTS: Thirty patients fulfilled inclusion criteria. Before Mitraclip implantation NYHA class was III in 83% and IV in 17% of patients; after CRT no patient experienced an improvement in FMR. There was a significant improvement in NYHA class from baseline to 6 months, which remained sustained at 12 and 24 months. The degree of FMR significantly improved from baseline to 6 months and from 6 to 12 months. There was left ventricle remodeling with significant reduction of LVESV and an increase of left ventricle ejection fraction at 6 and 12 months, while the opposite trend was noted between 12 and 24 months CONCLUSION: Treatment of moderate to severe FMR in CRT nonresponder is feasible, safe, and reasonably effective in reducing cardiac symptoms.

Unexpected challenging case of coronary sinus lead extraction.

An 84-year-old woman implanted with cardiac resynchronization therapy defibrillator underwent transvenous lead extraction 4 mo after the implant due to pocket infection. Atrial and right ventricular leads were easily extracted, while the attempt to remove the coronary sinus (CS) lead was unsuccessful. A few weeks later a new extraction procedure was performed in our center. A stepwise approach was used. Firstly, manual traction was unsuccessfully attempted, even with proper-sized locking stylet. Secondly, mechanical dilatation was used with a single inner sheath placed close to the CS ostium. Finally, a modified sub-selector sheath was successfully advanced over the electrode until it was free of the binding tissue. The post-extraction lead examination showed an unexpected fibrosis around the tip. No complications occurred during the postoperative course. Fibrous adhesions could be found in CS leads recently implanted requiring non-standard techniques for its transvenous extraction.

Ventricular arrhythmias in aortic valve stenosis before and after transcatheter aortic valve implantation.

AIMS: Transcatheter aortic valve implantation (TAVI) is a therapeutic treatment for patients with severe aortic stenosis (AS) at high surgical risk. Although the procedure is associated with a reduction in total mortality, there are no data regarding changing in the incidence of premature ventricular contractions (PVCs) and ventricular arrhythmias (VAs) after TAVI. The aim of this study was to assess the incidence of VAs before and after TAVI. METHODS AND RESULTS: We enrolled 237 patients who underwent TAVI at our centre. Ninety-one patients were excluded for the following reasons: presence of prior permanent pacemaker (PPM) (n = 20), new PPM implant after TAVI (n = 48), death during the follow-up period (n = 16), and lost at follow-up (n = 7). Finally, 146 patients were included in our analysis. The presence of VAs was evaluated in all patients recording a 24 h Holter monitoring before the procedure and after 1 and 12 months. Ventricular arrhythmias were classified according to a modified Lown grading system. Before the procedure, isolates PVCs (grade 1-2 of Lown grading system) were present in 34.9% of patients (n = 51). Complex PVCs (grade 3-4a-4b of Lown grading system) were present in 48.6% of the population (multifocal PVCs in 32 patients, 21.9%; pairs in 25 patients, 17.1%; ventricular tachycardia in 14 patients, 9.6%). One month after the procedure, we observed statistically significant incidence decrease of arrhythmias of grade 3 (from 21.9 to 17.1%) and grade 4 (pairs from 17.1 to 12.3%; ventricular tachycardia from 9.6 to 4.8%). After 12 months, there was a further significant reduction in the frequency and severity of PVCs. In particular, 45.8% of patients had isolates PVCs (<30 in all given hours of monitoring in 45 patients, 30.8%; higher than 30 in any hour of monitoring in 22 patients, 15%) while the frequency of complex arrhythmias was reduced to 16.4% (multifocal PVCs in 13 patients, 9%; couplets 8 patients, 5.5% and ventricular tachycardia in 3 patients, 2.0%). The difference was statistically significant (P < 0.01). CONCLUSION: This study indicates that VAs are common in patients with AS. We observed a significant decrease in the incidence and severity of PVCs since the first month after TAVI. Furthermore, after 1 year follow-up there was a further and significant reduction in the frequency of complex PVCs. This may be related to the benefits determined by valve replacement on left ventricular function.

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.

Selection of patient for cardiac resynchronization therapy: role of QT corrected dispersion.

AIMS: About 30 to 50% of patients undergoing cardiac resynchronization therapy (CRT) may not show clinical or echocardiographic improvement, despite fulfilling guidelines recommendations for CRT. For this reason, we need a more accurate method to assess CRT eligibility. The aims of this study were to verify, on a 12-month follow-up, the usefulness of QT corrected dispersion (QTcD) in a patient's selection for CRT. METHODS: We stratified 53 patients who underwent CRT, into two groups based on the estimation of QTcD, that is, QTcD > 60 ms and QTcD ≤ 60 ms. In all patients were performed New York Heart Association (NYHA) class determination, six-minute walking test, QtcD, and QRS measurements, and complete echocardiographic assessment at 1, 3, 6, and 12 months after implantation. RESULTS: At baseline, there were no significant differences in clinical, echocardiographic, and electrocardiographic parameters duration between two groups. At 12-month follow-up between the two groups, there were significant differences in NYHA (1.2 ± 0.4 vs 2 ± 0.6; P < 0.01), six-minute walking distance (422 ± 68 vs 364 ± 68; P < 0.01), left ventricular (LV) ejection fraction (34 ± 7% vs 28 ± 6%; P < 0.01), LV end-diastolic diameter (57 ± 7 vs 63 ± 8; P < 0.01), and LV intraventricular dyssynchrony (24 ± 14 vs 39 ± 23; P < 0.01). CONCLUSION: This study suggests that QTc dispersion in addition to QRS duration could improve the sensitivity of electrocardiogram in a patient's selection for CRT.

Incidence rate and predictors of permanent pacemaker implantation after transcatheter aortic valve implantation with self-expanding CoreValve prosthesis.

BACKGROUND: Conduction disorders and permanent pacemaker (PPM) implantation are common complications in patients undergoing transcatheter aortic valve implantation (TAVI). Previous studies, evaluating small populations, have identified several different predictors of PPM implantation after TAVI. The aim of this study was to assess the incidence rate of conduction disorders and the predictors of postoperative PPM requirement in a large series of patients undergoing TAVI. METHODS: Data were analyzed from 181 consecutive patients at high-risk surgery who underwent TAVI at our institute between July 2007 and April 2011. All patients underwent implantation of the third-generation percutaneous self-expanding CoreValve® prosthesis (CoreValve, Inc., Irvine, CA, USA). In all patients, a 12-lead electrocardiogram and a 24-h holter monitoring was recorded before and after the procedure in order to assess the presence of conduction disorders. Clinical data, preoperative conduction disorders, echocardiographic patterns, and procedural data were tested as predictors of PPM implantation after TAVI. RESULTS: Left bundle branch block (LBBB) was the most common conduction disorder, with an incidence of 50.3% at discharge. Fifty-two (32.1%) patients developed a persistent complete AVB requiring PPM implantation. PPM implantation was strongly correlated with the presence of preoperative right bundle branch block (RBBB) which was found to be the only independent predictor of PPM implantation (HR 16.5, CI 3.3-82.3, p < 0.001). CONCLUSIONS: LBBB and PPM implantation requirement after TAVI are common occurrences using the self-expanding CoreValve prosthesis. In this large series of consecutive patients, only RBBB was found to be a strong predictor of PPM requirement.