DNA sequence capture and next-generation sequencing for the molecular diagnosis of genetic cardiomyopathies.

Hypertrophic cardiomyopathy is a relatively frequent disease with a prevalence of 0.2% worldwide and a remarkable genetic heterogeneity, with more than 30 causative genes reported to date. Current PCR-based strategies are inadequate for genomic investigations involving many candidate genes. Here, we report a next-generation sequencing procedure associated with DNA sequence capture that is able to sequence 202 cardiomyopathy-related genes simultaneously. We developed a complementary data analysis pipeline to select and prioritize genetic variants. The overall procedure can screen a large number of target genes simultaneously, thereby potentially revealing new disease-causing and modifier genes. By using this procedure, we analyzed hypertrophic cardiomyopathy patients in a shorter time and at a lower cost than with current procedures. The specificity of the next-generation sequencing-based procedure is at least as good as other techniques routinely used for mutation searching, and the sensitivity is much better. Analysis of the results showed some novel variants potentially involved in the pathogenesis of hypertrophic cardiomyopathy: a missense mutation in MYH7 and a nonsense variant in INS-IGF2 (patient 1), a splicing variant in MYBPC3 and an indel/frameshift variant in KCNQ1 (patient 2), and two concomitant variations in CACNA1C (patient 3). Sequencing of DNA from the three patients within a pool allowed detection of most variants identified in each individual patient, indicating that this approach is a feasible and cost-effective procedure.

LCAT cholesterol esterification is associated with the increase of ApoE/ApoA-I ratio during atherosclerosis progression in rabbit

Apolipoprotein A-I and Apolipoprotein E promote different steps of reverse cholesterol transport, including lecithin-cholesterol acyltransferase stimulation. Our aim was to study the changes in the levels of Apolipoprotein A-I, Apolipoprotein E, and lecithin-cholesterol acyltransferase activity during atherosclerosis progression in rabbits. Quantitative echocardiographic parameters were analyzed in order to evaluate, for the first time, whether atherosclerosis progression in rabbit is associated to apolipoproteins changes and alteration of indices of cardiac function, such as systolic strain and strain rate of the left ventricle. Atherosclerosis was induced by feeding rabbits for 8 weeks with 2 % cholesterol diet. The HDL levels of cholesterol and cholesteryl esters were measured by HPLC. The lecithin-cholesterol acyltransferase activity was evaluated both ex vivo, as cholesteryl esters/cholesterol molar ratio, and in vitro. Apolipoproteins levels were analyzed by ELISA. The HDL levels of cholesterol and cholesteryl esters increased, during treatment, up to 3.7- and 2.5-fold, respectively, compared to control animals. The lecithin-cholesterol acyltransferase activity in vitro was halved after 4 weeks. During cholesterol treatment, Apolipoprotein A-I level significantly decreased, whereas Apolipoprotein E concentration markedly increased. The molar ratio Apolipoprotein E/Apolipoprotein A-I was negatively correlated with the enzyme activity, and positively correlated with both increases in the intima-media thickness of common carotid wall and cardiac dysfunction signs, such as systolic strain and strain rate of the left ventricle (AU)

Orthotopic heart transplantation: two parts of the heart with two different arrhythmias.

An unusual case of two different types of atrial arrhythmia after orthotopic heart transplantation is reported: a macro-reentrant atrial tachycardia in the recipient atrium, and a common-type, counterclockwise, isthmus-dependent atrial flutter in the donor atrium. The clinical symptoms were caused by atrial flutter arising from the donor atrium. Radiofrequency catheter ablation of the electrically active, donor-derived portion of the cavotricuspid isthmus was performed successfully.

Which parameters describe the electrophysiological properties of successful slow pathway RF ablation in patients with common atrioventricular nodal reentrant tachycardia?

OBJECTIVE: Atrioventricular nodal reentrant tachycardia (AVNRT) accounts for about 60% of the patients presenting with paroxysmal supraventricular tachycardia. The radiofrequency (RF) catheter ablation of the slow atrioventricular (AV) node pathway is the preferred therapeutic approach in patients with AV node reentrant tachycardia. The aim of our study was describe the electrophysiological properties of successful slow pathway RF ablation in patients with common atrioventricular nodal reentrant tachycardia. METHODS: The study design was a retrospective analysis involving fifty consecutive patients (18 males; mean age of 39+/-22 years) who underwent slow pathway ablation because of AVNRT. RESULTS: Slow junctional beats with a cycle length longer than 550 ms were observed in 39 patients (79%); the presence of rapid junctional beats with a cycle length less than 550 ms was showed in 5 patients (10%). Moreover, in 32 of 50 patients (65%) duration of atrial electrogram more than 40 ms was noticed. Analyzing data reported, we found the statistically significant presence of slow junctional beats (p=0.001) and atrial electrogram >40 ms (p=0.05) in successful RF ablation procedures. CONCLUSION: In patients with AVNRT undergoing slow pathway ablation, the duration of atrial electrogram >40 ms and slow junctional beats with cycle length >550 ms during the application of RF energy describe the electrophysiological properties of successful slow pathway RF ablation.

Autonomic nervous system modulation before the onset of sustained atrioventricular nodal reentry tachycardia.

INTRODUCTION: Our study was designed to analyze dynamic changes in autonomic tone before the onset of typical sustained atrioventricular nodal reentry tachycardia (AVNRT) in a large group of patients without structural heart disease. MATERIALS AND METHODS: Twenty-four-hour Holter tapes from 42 consecutive patients (27 men and 15 women; aged 30 + or - 21 years) with several episodes of sustained typical AVNRT were analyzed. The diagnosis was validated by transesophageal electrophysiological study. The time-domain calculated parameters were SDNN, SDANN, rMSSD, pNN50; the frequency-domain parameters were low-frequency power (LF, 0.04-0.15 Hz), high-frequency power (HF, 0.15-0.40 Hz), very low-frequency power (VLF, 0.008 to 0.04 Hz) and LF/HF. The mean values in the hour before the onset of sustained AVNRT were compared with the mean values of 2 hours before and 1 hour after the onset of sustained AVNRT. RESULTS: The mean SDNN, rMSSD, pNN50, HF were significantly decreased during the hour preceding the onset of AVNRT, when compared to the mean values observed during the time periods selected. Instead, the LF values and LF/HF were increased before the onset of sustained AVNRT. No significant change in the VLF and atrial ectopic beats were observed. CONCLUSION: This study suggests that sustained typical AVNRT episodes are preceded by increase in adrenergic drive.

[Organization of care for adults with congenital heart disease]. / Modelli organizzativi per l'assistenza dei cardiopatici congeniti adulti.

The increasing number of adult patients with congenital heart disease and the better survival of patients with complex disease into adulthood, as a result of the success of pediatric cardiology and cardiac surgery over the last years, have increased the need for specific structures, the so-called grown-up congenital heart disease units, able to provide comprehensive care to these patients. Many of the adult patients with congenital heart disease will require, over time, further operations, urgent in-hospital admission for a wide range of complications such as arrhythmias, hemorrhage, heart failure and bacterial endocarditis. Furthermore, these patients may often experience despair due to their awareness of residual morbidities and the knowledge of possible early mortality, or limitations in their social lives and educational or occupational attainment. Provision of care for children with congenital heart disease is well established in most parts of the world. In contrast, clinical services for the adults with congenital heart disease are scarce. In this scenario, adult cardiologists are not always equipped to deal with the range ad complexity of grown-up patients with congenital heart disease, whereas pediatric cardiologists cannot be expected to manage the many acquired adult diseases in a pediatric medical environment.

Late cure after radiofrequency catheter ablation in a pediatric patient.

A 12-year-old female with the Wolff-Parkinson-White syndrome underwent an electrophysiologic study followed by radiofrequency catheter ablation of the left-lateral accessory pathway. After several unsuccessful attempts, the procedure was stopped because of early recurrence of accessory pathway conduction. Twenty-four hours after the procedure, the patient was found without ventricular pre-excitation pattern on the electrocardiogram. During a 12-month follow-up, the Wolff-Parkinson-White pattern was no longer present. A transesophageal electrophysiologic study showed no further tachycardia induction and the patient is still asymptomatic. This report raises the issue that ablation-induced lesions may evolve considerably during the first few days after ablation, leading to either recurrent accessory pathway conduction or long-lasting complete cure.

Electrophysiological evaluation of asymptomatic ventricular pre-excitation in children and adolescents.

BACKGROUND: Diagnostic assessment and treatment have been described in detail in symptomatic WPW syndrome, but little information exists about significance and prognosis of an incidentally found ventricular pre-excitation (VPE) in asymptomatic children. The aim of the study was to evaluate, retrospectively, the role of electrophysiological study (EPS) in the assessment of the arrhythmic risk in asymptomatic patients with VPE. MATERIAL AND METHODS: Sixty-two asymptomatic children and adolescents (38 M/24 F, aged 9.8+/-5.1 years) referred to our Division between 1996 and 2002 for an incidentally found VPE underwent an EPS for arrhythmic risk stratification. The following parameters were examined: anterograde effective refractory period of the accessory pathway (AP), the 1-to-1 conduction over the AP, the inducibility of atrio-ventricular re-entrant tachycardia (AVRT) and the inducibility of atrial fibrillation (AF) with measurement of minimal RR between two consecutive preexcitated QRS complexes, the average RR interval of all cycles, and the percentage of preexcitated QRS complexes. RESULT: During the EPS, 36 patients (58.1%) experienced sustained SVT. The tachycardia was initiated in the basal state in 22 patients and after isoproterenol in the other 14. Orthodromic AVRT (cycle length 305.9+/-48.5 ms) was recorded in 29 patients. In three patients, both orthodromic and antidromic AVRT were recorded, with different cycle length (CL). Antidromic AVRT alone (CL 239.5+/-13.7 ms) was recorded in four patients. AF was recorded in nine patients: in six patients, it was recorded after the induction of orthodromic or antidromic AVRT, in the other three cases AF was the first and only arrhythmic event. The minimal RR between two consecutive pre-excitated QRS ranged between 250-230 ms (mean 237.5+/-9.6 ms). In the 26 patients who presented no induced sustained tachycardia in the EPS, the 1:1 conduction over the AP ranged between 210 and 600 ms (mean 279.6+/-75.2 ms). CONCLUSIONS: Electrophysiological evaluation remains the gold standard for assessing risk of life-threatening arrhythmias in patients with VPE. However, a high proportion of healthy children and adolescents with VPE can experience sustained AVRT and/or AF during EPS. These results raise questions about the necessity of an aggressive treatment approach to prevent those "rare" cases of sudden death.

A "multisite" atrioventricular block.

A 6-year-old child, operated for a perimembranous ventricular septal defect, underwent an electrophysiologic study for the presence of first degree atrioventricular (AV) block and bifascicular block with episodes of type 1 and type 2 second degree AV block. Electrophysiologic study showed a considerable infra-His conduction delay (HV interval 170 ms) and spontaneous phases of infra-His type 1 second degree AV block. During incremental atrial pacing supra-His type 1 second degree AV block and 2:1 infra-His AV block were simultaneously observed and this condition persisted unmodified despite the intravenous injection of atropine. The block distal to the His bundle was considered functional.

Cryoenergy catheter ablation: a new technique for treatment of permanent junctional reciprocating tachycardia in children.

INTRODUCTION: Permanent junctional reciprocating tachycardia (PJRT) is an infrequent form of reciprocating tachycardia, almost incessant from childhood and usually refractory to drug therapy. Radiofrequency catheter ablation currently is the first-line therapy for PJRT, but its application in the septal region may be associated with complications. In contrast, cryoenergy has several advantages, such as the ability to test the effects of ablation while the lesion is still forming, thus reducing the number of ineffective, useless, and potentially harmful lesions. The aim of this study was to investigate the potential clinical utility of percutaneous cryoenergy catheter ablation for treatment of pediatric patients with PJRT. METHODS AND RESULTS: Four patients (age 14 +/- 5 years; mean +/- SD) with a clinical diagnosis of PJRT underwent catheter cryoablation. The ablation was successfully accomplished in 4 (100%) of 4 patients. The mean +/- SD number of cryoapplications was 1.8 +/- 0.8, and from 1 to 6 cryomappings were performed for each permanent cryolesion. The successful site was in the mid-septal region (2 patients), at the coronary sinus orifice (1 patient), and in the middle cardiac vein (1 patient). No complications with cryoablation were reported, nor was there prolongation of the AH interval during cryomapping or cryoablation. No pain was reported by patients during the cryoenergy catheter ablation procedure. PJRT recurrence occurred in 1 patient who underwent a second successful cryoablation procedure. CONCLUSION: The outcomes of cryoenergy catheter ablation in these 4 patients treated for PJRT suggest that cryoablation is a safe, effective, and pain-free technique for treating pediatric patients with PJRT.