Percutaneous Radiofrequency Septal Reduction for Hypertrophic Obstructive Cardiomyopathy in Children

Radiofrequency ablation in patients with obstructive hypertrophic cardiomyopathy: An updated comprehensive review and meta-analysis

BACKGROUND

Radiofrequency catheter ablation (RFCA) has emerged as a therapeutic option for surgical myectomy and alcohol septal ablation (ASA) in patients with hypertrophic obstructive cardiomyopathy (HOCM), but its efficacy remains unclear.

AIM

Due to limited research on RFCA for HCM, there is an ongoing attempt to assess its efficacy and safety.

METHODS

PubMed, Embase, and Scopus were systematically searched for studies assessing the efficacy outcomes for patients with HOCM who underwent RFCA. Mean differences (MDs) with 95% confidence intervals (CIs) were computed using a random-effects model and heterogeneity was assessed using I2 statistics.

RESULTS

We included 11 studies comprising 470 patients, of whom 34.6% were female. The mean patient age ranged from 43.7 to 60.7 years. During the follow-up after RFCA, there was a significant decrease in the left ventricular outflow tract (LVOT) gradient at rest (MD -60.25 mmHg; 95% CI [-70.53;-59.14 mmHg]; p < 0.01) and during stimulation (MD -83.56 mmHg; 95% CI [-100.36;-66.76 mmHg]; p < 0.01). Moreover, RFCA reduced interventricular septum (IVS) thickness (MD -3.61 mm; 95% CI [-5.64; -1.59 mm]; p = 0.01) and New York Heart Association (NYHA) class (MD -1.46; 95% CI [-1.69; -1.24]; p < 0.01).

CONCLUSIONS

In patients with HOCM, RFCA was associated with an improved NYHA class, reduced IVS thickness, and decreased LVOT gradient at rest and with stimulation.

Evolving Strategies for the Management of Obstructive Hypertrophic Cardiomyopathy

For many years, treatment of hypertrophic cardiomyopathy (HCM) has focused on non-disease-specific therapies. Cardiac myosin modulators (ie, mavacamten and aficamten) reduce the pathologic actin-myosin interactions that are characteristic of HCM, leading to improved cardiac energetics and reduction in hypercontractility. Several recently published randomized clinical trials have demonstrated that mavacamten improves exercise capacity, left ventricular outflow tract obstruction and symptoms in patients with obstructive HCM and may delay the need for septal-reduction therapy. Long-term data in real-world populations will be needed to fully assess the safety and efficacy of mavacamten. Importantly, HCM is a complex and heterogeneous disease, and not all patients will respond to mavacamten; therefore, careful patient selection and shared decision making will be necessary in guiding the use of mavacamten in obstructive HCM.

Invasive Management of Hypertrophic Cardiomyopathy With Clinically Important Obstruction: Catheter Intervention Is Superior

Hypertrophic cardiomyopathy is a common inherited cardiac condition where the myocardium progressively thickens in the absence of abnormal loading conditions. Left ventricular hypertrophy often leads to outflow tract obstruction, and this confers significant mortality and morbidity implications. Septal reduction therapies aim to relieve the obstruction in an attempt to reduce the burden of symptoms and potentially improve prognosis. However, both surgical and catheter-based approaches to septal reduction carry risks. At present, international guidelines and expert consensus statements suggest surgical myomectomy is the gold-standard treatment. In this point-counterpoint review, we discuss why in our opinion this recommendation should be reconsidered. We hope to cover the history of catheter based septal reduction therapies and the significant advances made over the last two decades. We also hope to show why we believe the current evidence shows catheter-based alcohol septal ablation is superior to surgical myomectomy.

A Narrative Review of Emerging Therapies for Hypertrophic Obstructive Cardiomyopathy

Hypertrophic obstructive cardiomyopathy is a hereditary condition that affects myocardial contraction. In case of failure of pharmacological treatment, alternative approaches might be used that include surgical myectomy, percutaneous transluminal septal myocardial ablation, and radiofrequency ablation. In respect of long-term advantages, surgical septal myectomy remains the therapy of choice for symptomatic hypertrophic obstructive cardiomyopathy. Alcohol septal ablation has been considered an alternative to surgical myectomy, which confers the benefits of a shorter hospital stay, less discomfort, and fewer complications. However, only expert operators should perform it on carefully chosen patients. Further, radiofrequency septal ablation reduces the left ventricular outflow tract gradient and improves the NYHA functional class of patients with hypertrophic obstructive cardiomyopathy, despite complications like cardiac tamponade and atrioventricular block. Further research with a larger sample size is required to compare the radiofrequency approach with established invasive treatment methods for hypertrophic obstructive cardiomyopathy. Septal myectomy has low morbidity and mortality rates, making it the preferred procedure; however, the efficacy and morbidity remain debatable. Advances in invasive techniques, including percutaneous septal radiofrequency ablation and transcatheter myotomy, have provided alternative approaches for reducing left ventricular outflow tract (LVOT) obstruction in patients who are not candidates for traditional surgical septal myectomy. Candidates for alcohol and radiofrequency septal ablation include patients with symptomatic hypertrophic obstructive cardiomyopathy, older adults, and those with multiple comorbidities.

Radiofrequency ablation in patients with obstructive hypertrophic cardiomyopathy: A systematic review and meta-analysis

Study objective

Hypertrophic cardiomyopathy (HCM) is a genetic disease that can cause left ventricular outflow tract (LVOT) obstruction. This study analyzed the efficacy of radiofrequency ablation (RA) in improving clinical and hemodynamic factors in patients receiving obstructive HCM refractory treatment. This evaluation was necessary because of the small number of studies on the effectiveness of this technique for obstructive HCM in the existing literature.

Design

We used the PubMed, Embase, and Science Direct databases to identify randomized clinical trials and observational studies addressing the clinical and hemodynamic outcomes before and after RA in patients with HCM.

Participants

We selected six articles published between 2011 and 2022, comprising 304 patients (mean age: 45 years).

Interventions

We performed a bias assessment using the ROBINS I tool, and meta-analysis processing was performed using the STATA program (v.16.0).

Results

The left ventricular outflow tract (LVOT) gradient at rest and with stimulation decreased by 58.78 mmHg (p = 0.001) and 70.38 mmHg (total effect Z = 21.62; p < 0.0001), respectively. Additionally, the New York Heart Association (NYHA) functional class decreased by 0.43 (p = 0.001), indicating symptomatic and hemodynamic improvements. Furthermore, we observed a significant reduction in septal thickness (by 4 mm; p = 0.001).

Conclusions

RA improved the NYHA functional class and LVOT gradient at rest and with stimulation and reduced septal thickness. These results suggest that RA is effective in patients refractory to pharmacological therapy and unsuitable for alcohol septal ablation or myectomy. However, more studies, including randomized clinical trials, should be conducted to define the role of RA in interventional therapies.

Endocardial Radiofrequency Ablation vs. Septal Myectomy in Patients With Hypertrophic Obstructive Cardiomyopathy: A Systematic Review and Meta-Analysis

Background

Septal myectomy (SM) has been the gold standard therapy for most patients with hypertrophic obstructive cardiomyopathy (HOCM). Endocardial radiofrequency ablation of septal hypertrophy (ERASH) is a novel treatment for septal reduction. We aimed to assess the efficacy and safety between two treatment strategies.

Methods

We searched PubMed, Web of Science, Cochrane Library, and Embase databases to identify relevant studies published up to March 2021. Random-effect models were used to calculate standardized mean difference (SMD) and 95% confidence intervals (CIs) for resting left ventricular outflow tract gradient (LVOTG) and septal thickness.

Results

Twenty-five studies are included in this review, eighteen studies for SM and seven studies for ERASH. During follow-up, there were significant reductions of the mean resting LVOTG in adults (SM groups: SMD = −3.03, 95% CI [−3.62 to −2.44]; ERASH groups: SMD = −1.95, 95% CI [−2.45 to −1.45]) and children (SM groups: SMD = −2.67, 95% CI [−3.21 to −2.12]; ERASH groups: SMD= −2.37, 95% CI [−3.02 to −1.73]) after the septal reduction therapies. For adults, SM groups contributed to more obvious reduction than ERASH groups in interventricular septal thickness (SM groups: SMD = −1.82, 95% CI [−2.29 to −1.34]; ERASH groups: SMD = −0.43, 95% CI [−1.00 to 0.13]). The improvement of the New York Heart Association class was similar in the two groups (SM groups: 46.4%; ERASH groups: 46.7%). The periprocedural mortality in SM and ERASH were 1.1 and 1.8%, respectively.

Conclusions

This systematic review suggests that SM is superior to ERASH in the treatment of HOCM. But for the patients who are at risk for open cardiac surgeries or prefer a less invasive approach, ERASH might be an optional approach.

Selective Interventricular Septal Radiofrequency Ablation in Patients With Hypertrophic Obstructive Cardiomyopathy: Who Can Benefit?

Introduction: Septal mass reduction is beneficial for hypertrophic obstructive cardiomyopathy (HOCM) patients with severe left ventricular outflow (LVOT) gradient and symptoms, with surgical myectomy or alcohol septal ablation (ASA) currently recommended in selected patients. Radiofrequency (RF) ablation of hypertrophied septum has been published as a novel method to alleviate LVOT obstruction in small populations. This study aims to investigate factors influencing clinical outcomes of radiofrequency septum ablation.

Methods and Results: In this study, 20 patients with HOCM who underwent endocardial ablation were included. Echocardiography and cardiac MRI (CMR) data was collected and analyzed pre- and (or) post- procedure. Nineteen patients underwent ablation successfully, while ablation was aborted in one patient with prior RBBB due to transient complete atrioventricular block (AVB). After 6 months of follow-up, NYHA heart functional class improved from III (2 - 3) to II (1 - 2) (p < 0.001), and resting LVOT gradient was significantly reduced (87.6 ± 29.5 mmHg vs. 48.1 ± 29.7, p < 0.001). LVOT gradient reduction was significantly higher in patients with limited basal septal hypertrophy (60.9 ± 8.3 vs. 27.9 ± 7.1, p = 0.01), shorter anterior mitral leaflet (56.1 ± 6.4 vs. 20.4 ± 5.0, p < 0.01), and normally positioned papillary muscle (36.9 ± 7.1 vs. 75.0 ± 6.3, p < 0.05).

Conclusions: Endocardial septal ablation appears to be a safe and effective procedure for alleviating LVOT gradient in patients with HOCM, especially in those with limited basal septal hypertrophy, shorter anterior mitral leaflet, and normal positioned papillary muscle.

Safety and efficacy of alcohol septal ablation in adolescents and young adults with hypertrophic obstructive cardiomyopathy

INTRODUCTION

Data regarding alcohol septal ablation (ASA) in young patients with hypertrophic obstructive cardiomyopathy (HOCM) are scarce. The purpose of our study is to evaluate the safety and efficacy of ASA in patients ≤ 25 years.

METHODS AND RESULTS

All ASAs between 2002 and 2020 at our institution were assigned to a group of patients 14-25 years of age (group 1) and a reference group > 25 years (group 2). 1,264 procedures were analysed in group 2 (58.6 ± 13.5 years) and 41 procedures in group 1 (20.9 ± 3.3 years). The baseline interventricular septal diameter (IVSD) was higher in group 1 (26.0 ± 6.5 mm vs. 21.3 ± 4.4 mm; p < 0.0001). There was no difference in baseline left ventricular outflow tract gradient (LVOTG) (group 1: 54.4 ± 24.4 mmHg; group 2: 52.4 ± 36.6 mmHg; p = n.s.). A previous cardiac device was more often observed in group 1 (31.7% vs. 9.0%; p < 0.0001). Symptoms were improved after 6 months (group 1: mean NYHA class 2.5 at baseline and 1.3 at FU; p < 0.0001; group 2: mean NYHA class 2.7 at baseline and 1.4 at FU; p <0 .0001). IVSD (group 1: 20.3 ± 8.2 mm; group 2: 16.8 ± 5.7 mm; p < 0.0001 for each group compared to baseline) and LVOTG improved during FU (group 1: 25.5 ± 20.0 mmHg; group 2: 22.1 ± 21.7 mmHg; p < 0.0001 for each group). Intrahospital mortality was 0.0% in patients 14-25 years and 0.9% in the reference group. Persistent AV-block was observed in 12.2% of the group 1 and 15.9% of the group 2 patients (p = n.s.).

CONCLUSION

ASA is safe and effective in HOCM patients 14-25 years of age in experienced centres.

Acute and chronic effects of endocardial radiofrequency ablation of septal hypertrophy in HOCM

INTRODUCTION

Endocardial radiofrequency ablation of septal hypertrophy (ERASH) is an alternative to alcohol septal ablation (ASA) or surgical myectomy for hypertrophic obstructive cardiomyopathy (HOCM). Several studies have confirmed that septal radiofrequency ablation leads to a significant reduction in the left ventricular outflow tract gradient.

OBJECTIVES

We aimed to report the outcomes of 41 patients who underwent ERASH with a focus on severe complications.

METHODS

Since 2004, 41 patients with HOCM (age: 58.2 ± 13 years) underwent ERASH at our institution. ERASH was performed, since ASA was ineffective (26 patients) or not possible (15 patients).

RESULTS

The left ventricular outflow tract and the right ventricular septum were ablated in 26 and 15 patients, respectively. ERASH resulted in a significant reduction in acute gradient during the session and the results persisted during the 6-month follow-up (67% gradient reduction at rest and 73% after provocation, p = .0002). Pacemaker dependency after ERASH was 29% and pericardial tamponade occurred in two patients. In four patients, ERASH induced a paradoxical increase in obstruction (PIO), beginning suddenly at 30 min after the procedure and leading to lethal shock in one patient. PIO was not observed after ERASH from the right ventricular aspect.

CONCLUSION

Morbidity and mortality after ERASH were higher than those after ASA. PIO, a life-threatening complication, was observed in 9% of the patients. Our data indicate that ERASH might be considered in patients who are not candidates for surgical myectomy or ASA.

Childhood Hypertrophic Cardiomyopathy: A Disease of the Cardiac Sarcomere

Hypertrophic cardiomyopathy is the second most common cause of cardiomyopathy presenting during childhood and whilst its underlying aetiology is variable, the majority of disease is caused by sarcomeric protein gene variants. Sarcomeric disease can present at any age with highly variable disease phenotype, progression and outcomes. The majority have good childhood-outcomes with reported 5-year survival rates above 80%. However, childhood onset disease is associated with considerable life-long morbidity and mortality, including a higher SCD rate during childhood than seen in adults. Management is currently focused on relieving symptoms and preventing disease-related complications, but the possibility of future disease-modifying therapies offers an exciting opportunity to modulate disease expression and outcomes in these young patients.

Septal Reduction Using Transvenous Intramyocardial Cerclage Radiofrequency Ablation: Preclinical Feasibility

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Surgical myectomy is morbid and transcoronary alcohol septal ablation can result in geographic miss or occasional nontarget injury.

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We developed a transvenous intraseptal radiofrequency ablation technique (cerclage ablation method) to overcome the shortcomings of surgical myectomy and alcohol septal ablation.

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We delivered dedicated intraseptal radiofrequency ablation catheter into the ventricular septum through the coronary sinus and a septal vein. The ablated volume of myocardium was larger at higher electrode temperatures and using an irrigated-ablation mode in vitro. Cerclage ablation was successful in all in vivo attempts and induced a focal regional wall motion abnormality at later follow-up.

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This study presents in vivo evidence of the feasibility, effectiveness, and safety of cerclage ablation method to debulk interventricular septal myocardium.

Debulking of left ventricular septal mass is typically accomplished using surgical myectomy, which is morbid, or using transcoronary alcohol septal ablation, which can result in geographic miss and occasional catastrophic nontarget coronary injury. The authors developed and tested operational parameters in vitro and vivo for a device to accomplish transvenous intraseptal radiofrequency ablation to reduce ventricular septal mass using a technique derived from mitral cerclage, which the authors call cerclage ablation. Cerclage ablation appeared feasible in vitro and safe and effective in vivo. Cerclage ablation is an attractive new approach to debulk the interventricular septum in obstructive hypertrophic cardiomyopathy. These data support clinical investigation.

Efficacy and safety of radiofrequency ablation for hypertrophic obstructive cardiomyopathy: A systematic review and meta-analysis

Background

Although radiofrequency ablation is widely used in the treatment of arrhythmias, its role in septal reduction therapy of hypertrophic obstructive cardiomyopathy (HOCM) is unclear. This meta‐analysis aimed to assess the efficacy and safety of radiofrequency septal ablation for HOCM.

Hypothesis

Radiofrequency septal ablation is effective and safe for relieving obstruction and improving exercise capacity in patients with HOCM.

Methods

A systematic review of eligible studies that reported outcomes of patients with HOCM who underwent radiofrequency septal ablation was performed using PubMed, Embase, Cochrane, ProQuest, Scopus, ScienceDirect, and Web of Science database. Pooled estimates were calculated using random‐effects meta‐analysis. Methodological quality was assessed using the Newcastle‐Ottawa scale. Publication bias and sensitivity analyses were also performed.

Results

Eight studies with 91 patients (mean follow‐up 11.6 months) were included. The left ventricular outflow tract (LVOT) gradient at rest decreased significantly after radiofrequency septal ablation (pooled reduction: −58.8 mmHg; 95% confidence interval [CI] −64.3 to −53.5). A reduction was also found in the provoked LVOT gradient with a pooled reduction of −97.6 mmHg (95% CI: −124.4 to −87.1). An improvement of the New York Heart Association classification (mean: −1.4; 95% CI: −1.6 to −1.2) was found during follow‐up. The change in septal thickness was minimal and not statistically significant. Two procedure‐related deaths were documented, and complete heart block occurred in eight patients.

Conclusions

Radiofrequency septal ablation is effective and safe for relieving LVOT obstruction and improving exercise capacity in patients with HOCM.

Role of endocardial septal ablation in the treatment of hypertrophic obstructive cardiomyopathy

Septal reduction therapy is accepted as a first therapeutic option for symptomatic drug-resistant hypertrophic obstructive cardiomyopathy (HOCM). Although, surgical septal myectomy is the gold standard method, alcohol septal ablation is a well-studied alternative approach in the patients with suitable anatomy. Endocardial septal ablation (ESA) therapy was relatively new defined modality and outcomes of the procedure were not clearly elucidated yet. We aimed to review the clinical aspects of ESA procedure and provide some historical background.

Emerging pharmacologic and structural therapies for hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is the most common inherited heart disease. Although it was first described over 50 years ago, there has been little in the way of novel disease-specific therapeutic development for these patients. Current treatment practice largely aims at symptomatic control using old drugs made for other diseases and does little to modify the disease course. Septal reduction by surgical myectomy or percutaneous alcohol septal ablation are well-established treatments for pharmacologic-refractory left ventricular outflow tract obstruction in hypertrophic cardiomyopathy patients. In recent years, there has been a relative surge in the development of innovative therapeutics, which aim to target the complex molecular pathophysiology and resulting hemodynamics that underlie hypertrophic cardiomyopathy. Herein, we review the new and emerging therapeutics for hypertrophic cardiomyopathy, which include pharmacologic attenuation of sarcomeric calcium sensitivity, allosteric inhibition of cardiac myosin, myocardial metabolic modulation, and renin-angiotensin-aldosterone system inhibition, as well as structural intervention by percutaneous mitral valve plication and endocardial radiofrequency ablation of septal hypertrophy. In conclusion, while further development of these therapeutic strategies is ongoing, they each mark a significant and promising advancement in treatment for hypertrophic cardiomyopathy patients.

Hypertrophic Cardiomyopathy-Past, Present and Future

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy with a prevalence of 1 in 500 in the general population. Since the first pathological case series at post mortem in 1957, we have come a long way in its understanding, diagnosis and management. Here, we will describe the history of our understanding of HCM including the initial disease findings, diagnostic methods and treatment options. We will review the current guidelines for the diagnosis and management of HCM, current gaps in the evidence base and discuss the new and promising developments in this field.

Radiofrequency septal reduction in symptomatic hypertrophic obstructive cardiomyopathy

BACKGROUND

Alcohol septal ablation remains the only approved nonsurgical therapeutic alternative for patients with drug-resistant hypertrophic obstructive cardiomyopathy (HOCM). Radiofrequency (RF) ablation offers another option for treating HOCM.

OBJECTIVE

The purpose of this study was to determine whether irrigated RF ablation can reduce symptomatic outflow tract obstruction in adults with HOCM.

METHODS

Patients with symptomatic HOCM and an outflow gradient of >50 mm Hg despite medication were offered RF ablation. In 11 patients, the hypertrophied interventricular septum was localized on a 3-dimensional mapping system and ablated via a transmitral or retrograde aortic approach.

RESULTS

Ten of 11(91%) patients had a significant and persistent reduction in resting and provocable left ventricular outflow tract gradients. Mean resting gradients at 12 months postprocedure were reduced by 85% (66.7 mm Hg at baseline to 10.0 mm Hg at 12 months); mean provocable gradients were reduced by 85% from baseline (136.2 mm Hg at baseline to 20.0 mm Hg at 12 months). Functional New York Heart Association heart classification improved from class 3.0 ± 0.0 in all patients to class mean of 1.8 ± 0.8.

CONCLUSION

RF septal ablation for the treatment of HOCM is a safe therapeutic option that allows for significant reduction in left ventricular outflow tract gradients, improvement in symptoms, and increase in efficacy rates comparable to reported rates for alcohol septal ablation.

A novel approach in the use of radiofrequency catheter ablation of septal hypertrophy in hypertrophic obstructive cardiomyopathy

Objective

Alcohol septal ablation (ASA) is a therapeutic alternative to surgical myectomy in patients with hypertrophic obstructive cardiomyopathy (HOCM). However, the anatomical variability of the septal branch, risk of complete heart block, and late onset ventricular arrhythmias are limitations to its therapeutic usage. There is recent interest in the use of radiofrequency catheter ablation (RFCA) as a therapeutic option in HOCM. We aimed to assess the safety and efficacy of RFCA in the treatment of symptomatic HOCM.

Methods

Seven patients with symptomatic HOCM (mean age 43.7 ± 15.6 years, five males), and significant left ventricular outflow tract (LVOT) gradient despite optimal drug therapy, underwent ablation of the hypertrophied interventricular septum. These patients had unfavorable anatomy for ASA. Ablation was performed under 3D electro-anatomical system guidance using an open irrigated tip catheter. The region of maximal LV septal bulge as seen on intracardiac echocardiography was targeted. Patients were followed up at 1, 6, and 12 months post-procedure.

Results

The mean baseline LVOT gradient by Doppler echocardiography was 81 ± 14.8 mm of Hg which reduced to 48.5 ± 22.6 (p = 0.0004), 49.8 ± 19.3 (p = 0.0004), and 42.8 ± 26.1 mm of Hg (p = 0.05) at 1, 6, and 12 months respectively. Symptoms improved at least by one NYHA class in all but one patient. One patient developed transient pulmonary edema post-RFA. There were no other complications.

Conclusion

RFCA of the hypertrophied septum causes sustained reduction in the LVOT gradient and symptomatic improvement among patients with HOCM. Electroanatomical mapping helps to perform the procedure safely.

Intervention in HCM: patient selection, procedural approach and emerging techniques in alcohol septal ablation

Hypertrophic cardiomyopathy (HCM) is a highly heterogeneous disease with varied patterns of hypertrophy. Basal septal hypertrophy and systolic anterior motion (SAM) of the mitral valve (MV) are the key pathophysiological components to left ventricular outflow tract (LVOT) obstruction in HCM. LVOT is associated with higher morbidity and mortality in patients with HCM. Percutaneous septal reduction therapy with alcohol septal ablation (ASA) can lead to a significant improvement in left ventricle haemodynamics, patient symptoms and perhaps prognosis. ASA delivers pure alcohol to an area of myocardium via septal coronary arteries; this creates damage to tissue akin to a myocardial infarction. The basal septal myocardium involved in SAM-septal contact is the target for this iatrogenic infarct. Appropriate patient selection and accurate delivery of alcohol are critical to safe and effective ASA. Securing the correct diagnosis and ensuring suitable cardiac anatomy are essential before considering ASA. Pre-procedural planning and intra-procedural imaging guidance are important to delivering precise damage to the desired area. The procedure is performed worldwide and is generally safe; the need for a pacemaker is the most prominent complication. It is successful in the majority of patients but room for improvement exists. New techniques have been proposed to perform percutaneous septal reduction. We present a review of the relevant pathophysiology, current methods and a summary of available evidence for ASA. We also provide a glimpse into emerging techniques to deliver percutaneous septal reduction therapy.

Update on heart failure, heart transplant, congenital heart disease, and clinical cardiology

In the year 2012, 3 scientific sections-heart failure and transplant, congenital heart disease, and clinical cardiology-are presented together in the same article. The most relevant development in the area of heart failure and transplantation is the 2012 publication of the European guidelines for heart failure. These describe new possibilities for some drugs (eplerenone and ivabradine); expand the criteria for resynchronization, ventricular assist, and peritoneal dialysis; and cover possibilities of percutaneous repair of the mitral valve (MitraClip(®)). The survival of children with hypoplastic left heart syndrome in congenital heart diseases has improved significantly. Instructions for percutaneous techniques and devices have been revised and modified for the treatment of atrial septal defects, ostium secundum, and ventricular septal defects. Hybrid procedures for addressing structural congenital heart defects have become more widespread. In the area of clinical cardiology studies have demonstrated that percutaneous prosthesis implantation has lower mortality than surgical implantation. Use of the CHA2DS2-VASc criteria and of new anticoagulants (dabigatran, rivaroxaban and apixaban) is also recommended. In addition, the development of new sequencing techniques has enabled the analysis of multiple genes.

Biventricular / left ventricular pacing in hypertrophic obstructive cardiomyopathy: an overview

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant inherited genetic disease characterized by compensatory pathological left ventricle (LV) hypertrophy due to sarcomere dysfunction. In an important proportion of patients with HCM, the site and extent of cardiac hypertrophy results in severe obstruction to LV outflow tract (LVOT), contributing to disabling symptoms and increasing the risk of sudden cardiac death (SCD). In patients with progressive and/or refractory symptoms despite optimal pharmacological treatment, invasive therapies that diminish or abolish LVOT obstruction relieve heart failure-related symptoms, improve quality of life and could be associated with long-term survival similar to that observed in the general population. The gold standard in this respect is surgical septal myectomy, which might be supplementary associated with a reduction in SCD. Percutaneous techniques, particularly alcohol septal ablation (ASA) and more recently radiofrequency (RF) septal ablation, can achieve LVOT gradient reduction and symptomatic benefit in a large proportion of HOCM patients at the cost of a supposedly limited septal myocardial necrosis and a 10-20% risk of chronic atrioventricular block. After an initial period of enthusiasm, standard DDD pacing failed to show in randomized trials significant LVOT gradient reductions and objective improvement in exercise capacity. However, case reports and recent small pilot studies suggested that atrial synchronous LV or biventricular (biV) pacing significantly reduce LVOT obstruction and improve symptoms (acutely as well as long-term) in a large proportion of severely symptomatic HOCM patients not suitable to other gradient reduction therapies. Moreover, biV/LV pacing in HOCM seems to be associated with significant LV reverse remodelling.