Paolo De Filippo

A contemporary European experience with surgical septal myectomy in hypertrophic cardiomyopathy

Aims The recent American College of Cardiology and American Heart Association Guidelines on hypertrophic cardiomyopathy (HCM) have confirmed surgical myectomy as the gold standard for non-pharmacological treatment of obstructive HCM. However, during the last 15 years, an extensive use of alcohol septal ablation has led to the virtual extinction of myectomy programmes in several European countries. Therefore, many HCM candidates for myectomy in Europe cannot be offered the option of this procedure. The purpose of our study is to report the difficulties and results in developing a myectomy programme for HCM in a centre without previous experience with this procedure. Methods and results The clinical course is reported of 124 consecutive patients with obstructive HCM and heart failure symptoms who underwent myectomy at a single European centre between 1996 and 2010. The median follow-up was 20.3 months (inter-quartile range: 3.9–40.6 months). No patients were lost to follow-up. A cumulative incidence of HCM-related death after myectomy was 0.8, 3.3, and 11.2% at 1, 5, and 10 years, respectively, including one operative death (procedural mortality 0.8%). The left ventricular (LV) outflow gradient decreased from 95 ± 36 mmHg before surgery to 12 ± 6 mmHg at most recent evaluation (P < 0.001), with none of the patients having a significant residual LV outflow gradient. Of the 97 patients in New York Heart Association functional class III–IV before surgery, 93 (96%) were in class I–II at most recent evaluation (P < 0.001). Conclusion Our results show that the development of a myectomy programme at a centre without previous experience with this procedure is feasible and can lead to highly favourable clinical results.

Malignant Perinatal Variant of Long-QT Syndrome Caused by a Profoundly Dysfunctional Cardiac Sodium Channel

Background—Inherited cardiac arrhythmia susceptibility contributes to sudden death during infancy and may contribute to perinatal and neonatal mortality, but the molecular basis of this risk and the relationship to genetic disorders presenting later in life is unclear. We studied the functional and pharmacological properties of a novel de novo cardiac sodium channel gene (SCN5A) mutation associated with an extremely severe perinatal presentation of long-QT syndrome in unrelated probands of different ethnicity. Methods and Results—Two subjects exhibiting severe fetal and perinatal ventricular arrhythmias were screened for SCN5A mutations, and the functional properties of a novel missense mutation (G1631D) were determined by whole-cell patch clamp recording. In vitro electrophysiological studies revealed a profound defect in sodium channel function characterized by ≈10-fold slowing of inactivation, increased persistent current, slowing of recovery from inactivation, and depolarized voltage dependence of activation and inactivation. Single-channel recordings demonstrated increased frequency of late openings, prolonged mean open time, and increased latency to first opening for the mutant. Subjects carrying this mutation responded clinically to the combination of mexiletine with propranolol and survived. Pharmacologically, the mutant exhibited 2-fold greater tonic and use-dependent mexiletine block than wild-type channels. The mutant also exhibited enhanced tonic (2.4-fold) and use-dependent block (≈5-fold) by propranolol, and we observed additive effects of the 2 drugs on the mutant. Conclusions—Our study demonstrates the molecular basis for a malignant perinatal presentation of long-QT syndrome, illustrates novel functional and pharmacological properties of SCN5A-G1631D, which caused the disorder, and reveals therapeutic benefits of propranolol block of mutant sodium channels in this setting.

Device Longevity in a Contemporary Cohort of ICD/CRT-D Patients Undergoing Device Replacement.

The longevity of defibrillators (ICD) is extremely important from both a clinical and economic perspective. We studied the reasons for device replacement, the longevity of removed ICD, and the existence of possible factors associated with shorter service life.

Selective-site pacing in paediatric patients: a new application of the Select Secure system

AIMS The aim of this study was to evaluate the feasibility and reliability of selective-site pacing by means of a new lead system in a paediatric population. This lead system is composed of a 4.1 Fr, active-fixation lead and a steerable catheter that allows easy positioning in selective sites. METHODS AND RESULTS Thirty young patients (mean age 9.0 +/- 4.5 years, range 2-16 years) received a single- (10) or dual- (20) chamber pacemaker. The 3830 lead was implanted successfully in the targeted chambers in all patients. The selective RV sites of pacing in 26 of the patients were: 18 mid-septum, 5 outflow tract, 1 low-septum, and 2 LEVO-RV-Apex. In all patients, an intracardiac loop was left in order to avoid stretching of the lead with growth. Mean follow-up duration was 11 +/- 10 months. Atrial sensing and pacing thresholds were 3.2 +/- 1.7 mV and 0.8 +/- 0.6 V at 0.5 ms at implantation and 3.4 +/- 2.1 mV and 0.6 +/- 0.3 V at 0.5 ms at follow-up. Ventricular sensing and pacing thresholds were 12.1 +/- 4.9 and 0.7 +/- 0.4 V at 0.5 ms on implantation and 12.7 +/- 6.1 mV and 0.8 +/- 0.5 V at 0.5 ms at follow-up (P = NS). No adverse events were reported. CONCLUSION Select Secure is a promising system for selective-site pacing in children.

Intermuscular pocket for subcutaneous implantable cardioverter defibrillator: Single-center experience.

The subcutaneous implantable cardioverter defibrillator (S‐ICD) is a novel device now accepted in clinical practice for treating ventricular arrhythmias. In 14 consecutive patients, S‐ICD devices were placed in the virtual space between the anterior surface of the serratus anterior muscle and the posterior surface of the latissimus dorsi muscle. During a mean follow up of 9 months, no dislocations, infections, hematoma formations, or skin erosions were observed. Intermuscular implantation of the S‐ICD could be a reliable, safe, and appealing alternative to the standard subcutaneous placement.

Effectiveness of subcutaneous implantable cardioverter-defibrillator testing in patients with hypertrophic cardiomyopathy

BACKGROUND Subcutaneous ICD (S-ICD) is a promising option for Hypertrophic Cardiomyopathy (HCM) patients at risk of Sudden Cardiac Death (SCD). However, its effectiveness in terminating ventricular arrhythmias in HCM is yet unresolved. METHODS Consecutive HCM patients referred for S-ICD implantation were prospectively enrolled. Patients underwent one or two attempts of VF induction by the programmer. Successful conversion was defined as any 65J shock that terminated VF (not requiring rescue shocks). Clinical and instrumental parameters were analyzed to study predictors of conversion failure. RESULTS Fifty HCM patients (34 males, 40±16years) with a mean BMI of 25.2±4.4kg/m2 were evaluated. Mean ESC SCD risk of was 6.5±3.9% and maximal LV wall thickness (LVMWT) was 26±6mm. In 2/50 patients no arrhythmias were inducible, while in 7 (14%) only sustained ventricular tachycardia was induced and cardioverted. In the remaining 41 (82%) patients, 73 VF episodes were induced (1 episode in 14 and >1 in 27 patients). Of these, 4 (6%) spontaneously converted. In 68/69 (98%) the S-ICD successfully cardioverted, but failed in 1 (2%) patient, who needed rescue defibrillation. This patient was severely obese (BMI 36) and LVMWT of 25mm. VF was re-induced and successfully converted by the 80J reversed polarity S-ICD. CONCLUSIONS Acute DT at 65J at the implant showed the effectiveness of S-ICD in the recognition and termination of VT/VF in all HCM patients except one. Extreme LVH did not affect the performance of the device, whereas severe obesity was likely responsible for the single 65J failure.

Curative ablation in a 12-month-old baby with severe ventricular systolic dysfunction and incessant ventricular tachycardia

Cardiomyopathies in the paediatric population portend a poor prognosis being characterized by a particularly accelerated and therapy refractory clinical course.1,2 Recognition and effective treatment of potential secondary causes may play a crucial role, leading to recovery in a not negligible proportion of cases. Left-ventricular dysfunction associated with wide QRS tachycardia is a quite common presentation, depicting two possible clinical pictures: ventricular tachycardia complicating idiopathic cardiomyopathy and primary tachycardiomyopathy. The distinction between the two might be pivotal, particularly in the paediatric population since, recognition of a tachycardiomyopathy must prompt an aggressive rhythm control. In this context, the role of the conduction system is being recognized in many incessant tachycardias with or without an underlying structural heart disease.3,4 The two most clinically relevant scenarios are fascicular tachycardia and junctional ectopic tachycardia (JET).5 The former is usually sustained by a reentry within a diseased Purkinjie network or involving the surrounding ventricular myocardium. The latter is thought to be caused by abnormal automaticity within the atrioventricular junction, and thus usually display a narrow QRS. Although JET is more frequently associated with a known structural injury such as myocarditis or post-operative status, still it should be kept in mind in the differential diagnosis, since isolated-idiopathic cases have been described as well.6 These arrhythmias, when displaying an incessant course may be responsible for systolic impairment, independent of their specific individual prognosis.7 We are describing a case of a 12-month-old baby that presented with a severe systolic dysfunction and almost incessant wide QRS tachycardia causing rapidly worsening heart failure despite full medical therapy. The arrhythmia was finally diagnosed as idiopathic left-ventricular fascicular tachycardia (ILVT) at the invasive electrophysiologic study, and transcatheter ablation through transseptal route was performed. The procedure turned out to be effective both in eliminating the …

Ablation of Atrial Tachycardia From a Giant Left Superior Vena Cava Using Integration With Computed Tomographic Imaging

A 49-year-old woman affected by the Turner syndrome with a history of repaired congenital cardiomyopathy and persistent atrial tachycardia was referred to our center for radiofrequency ablation. At 11 years of age, she had undergone a surgical closure of an ostium secundum atrial septal defect (direct suture) combined with ligation of a persistent left superior vena cava, the embryological precursor of the ligament of Marshall, at the level of its connection to the coronary sinus. At hospitalization, her electrocardiogram showed an atrial tachycardia (cycle length 375 ms) with long phases of 1:1 atrioventricular conduction. Before the procedure, a computed tomography (CT) scan was performed to merge the anatomic data with the electrophysiological findings during the procedure (CARTO-MERGE, Biosense Webster, Inc, Diamond Bar, Calif). The preacquired CT image, processed with CARTO-MERGE system, showed the presence of a giant left superior vena cava (isolated from the coronary sinus) and a sinus venosus defect (SVD) associated with a right-sided anomalous pulmonary venous connection. In detail, both right superior pulmonary vein and right inferior pulmonary vein drained into the superior …

Subcutaneous implantable cardioverter defibrillator eligibility according to a novel automated screening tool and agreement with the standard manual electrocardiographic morphology tool

PurposeSince subcutaneous implantable cardioverter defibrillator (S-ICD) introduction, the pre-implant screening based on a dedicated manual ECG tool (MST) was required to assure adequate sensing by the S-ICD. A novel automated screening tool (AST) has been recently developed. We assessed and compared the pass rate with AST and MST, and we measured the agreement between screening tools.MethodsThree electrodes were positioned at locations mimicking the placement of the S-ICD, and ECG recordings were collected in the supine and standing postures at rest. The three sensing vectors were analyzed with the MST and the AST. Eligibility was defined by the presence of at least one or two appropriate vectors in both postures.ResultsA total of 235 patients with an indication to ICD and no need for permanent pacing were enrolled. At least one suitable vector was identified in 214 (91%) patients with MST and 221 (94%) patients with AST (p = 0.219). At least two vectors were appropriate in 162 (69%) patients with MST and 187 (80%) patients with AST (p = 0.008). Overall, out of 1587 ECG analyzed, 1035 (65%) qualifying leads were identified with MST and 1111 (70%) with AST (p = 0.004). The agreement between the results of MST and AST ECG analysis was moderate (Kappa = 0.570; standard error = 0.022; CI = 0.526–0.613). The results were consistent regardless of the underlying cardiomyopathy. The most frequent reason for screening failure with MST was a high-amplitude T-wave (31% of failures). With AST, 23% of recordings that failed with MST for high-amplitude T-wave were classified as acceptable.ConclusionThe AST is associated with higher pass rate than the standard MST. It seems more tolerant of high-amplitude T-waves. Consequently, the agreement between MST and AST findings was only moderate.

External closed-circuit cooling system for management of patients after device implantation: A feasibility study

BACKGROUND In the first 24h after pacemaker or implantable cardioverter/defibrillator (ICD) implantation or replacement, the occurrence of hematoma and pain in the surgically treated region is not infrequent and may result in re-intervention and/or more severe complications, such as infections. Currently, the post-implant phase management is very empiric. The aim of this study was to test the clinical applicability and usefulness of an external close-circuit cooling system for the management of the early post-implant period in patients with high risk of hematoma due to anticoagulant and/or antiplatelet therapy. METHODS We studied 135 patients (78M; 71±11years) with high risk of hematoma occurrence after pace-maker (63 patients) or ICD (72 patients) implantation or replacement. Immediately after the intervention, a closed-circuit cooling system (CAREPACE™ system, Zamar, Italy) was externally applied on the pre-pectoral region to each patient and maintained for 24h. The system has a compressive pad and a refrigerating circuit in which non-toxic glycolic fluid is pumped. The fluid temperature was set and kept at 5°C for the whole period. RESULTS The compressive and cooling effect of the system was well tolerated by all the patients at the temperature set. Four patients complained of noise due to machine operation, but in none the treatment was interrupted. The average length of hospital stay was 2.8±0.4days. No clinically significant hematoma was observed at discharge and after one month follow-up visit. CONCLUSIONS This new system can be used for the management of the early phase after device implantation or replacement and appears clinically useful and well tolerated. Further studies on a larger scale are needed to test the potential reduction of post-intervention complications and the cost-effectiveness of this device.