Impact of secondary mitral valve chordal cutting on valve geometry in obstructive hypertrophic cardiomyopathy with marked septal hypertrophy.

AIMS: In patients with obstructive hypertrophic cardiomyopathy (HCM) and mild septal thickness undergoing myectomy, resecting fibrotic anterior mitral leaflet (AML) secondary chordae moves the mitral valve (MV) away from the outflow tract and ejection flow, reducing the need for a deep septal excision. Aim of the present study was to assess whether chordal resection has similarly favourable effects in patients with important hypertrophy, who represent the majority of patients with obstructive HCM. METHODS AND RESULTS: The MV position in the ventricular cavity, assessed from echocardiography as AML-annulus ratio, was compared before and after chordal resection in 150 consecutive HCM patients with important (≥20 mm) and 62 with mild (≤19 mm) septal thickness undergoing myectomy. Preoperatively, MV position was displaced towards the septum to a similar extent in both groups. Postoperatively, AML-annulus ratio increased of an equal degree in both groups, from 0.43 ± 0.05 to 0.55 ± 0.06 (P < 0.001) a 28% increase, and from 0.43 ± 0.06 to 0.55 ± 0.06 (P < 0.001) a 26% increase, respectively, indicating a similar MV shift away from the outflow tract. When AML-annulus ratio was compared in the study cohort and 124 normal subjects, MV position was within normal range in <4% of patients preoperatively and normalized in >50% postoperatively. CONCLUSIONS: In obstructive HCM, displacement of the MV apparatus into the outflow tract interferes with the ejection flow. Resection of fibrotic secondary chordae moves the MV apparatus away from the outflow tract and enlarges the outflow area independently of septal thickness, facilitating septal myectomy by reducing the need for a deep muscular excision.

Congenital Muscular Mitral-Aortic Discontinuity Identified in Patients With Obstructive Hypertrophic Cardiomyopathy.

BACKGROUND: The mitral valve is often structurally abnormal in hypertrophic cardiomyopathy (HCM). However, the mechanisms responsible for these abnormalities remain controversial. In 2016 we identified, at myectomy, muscular mitral-aortic discontinuity in 5 young patients with obstructive HCM. OBJECTIVES: This study sought to confirm our preliminary findings and assess the prevalence of muscular mitral-aortic discontinuity in obstructive HCM. METHODS: At our center, from January 2017 to April 2018, the area between the anterior mitral leaflet and aortic valve was inspected at myectomy in 106 consecutive patients with HCM. RESULTS: Muscular mitral-aortic discontinuity was identified in 28 (26%) patients and was significantly more common in younger than older patients (age 39 ± 13 years vs. 58 ± 11 years; p < 0.001). Muscular discontinuity was present in each of 6 patients aged <30 years but only 1 (2.7%) of 37 aged ≥60 years. Pathogenic sarcomere mutations were identified in 22 (79%) of 28 patients with and 24 (31%) of 78 without discontinuity (p < 0.001) and were associated with discontinuity independently of age (p = 0.021). Discontinuity mean length was 7.3 mm and was inversely related to age (p = 0.022). At echocardiography, the anterior mitral leaflet was longer in patients with than those without discontinuity (34 ± 4 mm vs. 29 ± 5 mm; p < 0.001). CONCLUSIONS: We report, for the first time, muscular mitral-aortic discontinuity in HCM. At myectomy, a long muscular discontinuity displaced the anterior mitral leaflet toward the apex in most young patients, was significantly associated with sarcomere mutations independent of age, and was extremely uncommon in older patients. These findings suggest that a long muscular mitral-aortic discontinuity could predispose to the development of outflow obstruction in young patients with sarcomere mutations.

Short-term echocardiographic evaluation by global longitudinal strain in patients with heart failure treated with sacubitril/valsartan.

AIMS: The angiotensin receptor neprilysin inhibitor (ARNI) sacubitril/valsartan reduces mortality and hospitalizations in patients with heart failure and reduced ejection fraction (HFrEF). Favourable effects on haemodynamic and functional parameters have been observed in patients with HFrEF undergoing ARNI therapy, using standard transthoracic echocardiography. Global longitudinal strain (GLS) assessment uses a semi-automatic procedure to provide a reliable and repeatable method that improves the detection of early changes of contractile function. We aimed to assess the effects of ARNI on GLS and myocardial mechanics in patients with HFrEF. METHODS AND RESULTS: Thirty patients with New York Heart Association class II-III HFrEF were treated with ARNI and monitored using standard echocardiographic examination and GLS measurements at baseline, 3 months, and 6 months. ARNI therapy resulted in a significant reduction of ventricular volumes and a significant increase in left ventricular ejection fraction at 6 months but not 3 months by standard transthoracic echocardiography (left ventricular ejection fraction from 28 ± 8% at baseline to 34 ± 12% at 6 months, P < 0.001). Non-significant differences in the size of the left atrium, right ventricular function, and pulmonary pressures were found at 6 months. By using GLS, there was a progressive improvement of all strain parameters by 3 months. The improvement showed a progressive trend over time and maintained significance at 6 months: GLS 4ch -7.2 ± 4.8% at baseline vs. -7.5 ± 3.9% at 3 months (P = 0.025) and - 9.2 ± 5.2% at 6 months (P = 0.0001); AVG GLS -6.9 ± 4.3 at baseline vs. -7.9 ± 4.2 at 3 months (P = 0.04) and - 8.8 ± 4.4 at 6 months (P = 0.035); GLS endo 8.2 ± 4.8 at baseline vs. -9.0 ± 4.8 at 3 months (P = 0.05) and - 10.1 ± 5.1 at 6 months (P = 0.001). CONCLUSIONS: Sacubitril/valsartan induces an early benefit on left ventricular remodelling, which is captured by myocardial strain and not by standard echocardiography. Strain method represents a practical tool to assess early and minimal variations of left ventricular systolic function.

Role of Preoperative Cardiovascular Magnetic Resonance in Planning Ventricular Septal Myectomy in Patients With Obstructive Hypertrophic Cardiomyopathy.

In obstructive hypertrophic cardiomyopathy (HC), extreme heterogeneity of septal morphology makes septal myectomy particularly challenging. Although cardiovascular magnetic resonance (CMR) reconstructs ventricular anatomy with high spatial resolution, CMR is not used systematically to plan preoperatively septal myectomy. In this study, we report our results with using CMR to plan the extent of septal excision in 112 consecutive HC patients who subsequently underwent myectomy. Depth and length of the myectomy planned at CMR were compared with those of the septal muscle excised in a single piece in all patients. Anterior septum maximal thickness at CMR was 22 ± 5 mm and excised muscle thickness 9 ± 3 mm. Planned myectomy length was 35 ± 11 mm (range 17 to 65) and excised muscle length 38 ± 10 mm (range 10 to 70), indicating extension of septal resection to mid-cavity. Thickness and length of the planned myectomy showed a significant correlation with the excised muscle (R2 = 0.345; p <0.001; and R2 = 0.358; p <0.001, respectively). Deep septal crypts were identified at CMR in 12(11%) patients, preventing muscle excision from areas at increased risk of iatrogenic septal defect. Large aberrant muscle bundles that could decrease mid-cavity dimension were identified at CMR and excised in 26(23%) patients. In the 55 patients with postoperative CMR, qualitative comparison of pre and postoperative ventricular morphology showed a smooth and apically extended myectomy. In conclusion, CMR planning of septal myectomy provided high resolution images of septal morphology and allowed us to perform a standardized and apically extended septal excision that was associated with favorable outcome. Our novel approach could make myectomy more accessible to cardiovascular surgeons.

Takotsubo cardiomyopathy associated with Kounis syndrome: A clinical case of the "ATAK complex".

A 60-year-old female developed cardiac arrest after experiencing an anaphylactic shock during administration of plasma-expanders. An electrocardiogram registered after restoration of sinus rhythm showed mild ST-elevation in the anterior precordial leads and T waves changes followed by appearance of echocardiographic alterations of left ventricular apex kinesis. Coronary angiography revealed normal coronary arteries, and cardiovascular magnetic resonance confirmed apical ballooning with late gadolinium enhancement in the segments with abnormal contractility. This uncommon clinical case confirms how takotsubo and Kounis syndrome may converge in a single nosological entity, the so-called "ATAK complex" (Adrenaline, Tako-Tsubo, Anaphylaxis, and Kounis), with a specific management and prognostic implications. .

Risk stratification in the long-QT syndrome.

BACKGROUND: Mutations in potassium-channel genes KCNQ1 (LQT1 locus) and KCNH2 (LQT2 locus) and the sodium-channel gene SCN5A (LQT3 locus) are the most common causes of the long-QT syndrome. We stratified risk according to the genotype, in conjunction with other clinical variables such as sex and the length of the QT interval. METHODS: We evaluated 647 patients (386 with a mutation at the LQT1 locus, 206 with a mutation at the LQT2 locus, and 55 with a mutation at the LQT3 locus) from 193 consecutively genotyped families with the long-QT syndrome. The cumulative probability of a first cardiac event, defined as the occurrence of syncope, cardiac arrest, or sudden death before the age of 40 years and before the initiation of therapy, was determined according to genotype, sex, and the QT interval corrected for heart rate (QTc). Within each genotype we also assessed risk in the four categories derived from the combination of sex and QTc (<500 msec or > or =500 msec). RESULTS: The incidence of a first cardiac event before the age of 40 years and before the initiation of therapy was lower among patients with a mutation at the LQT1 locus (30 percent) than among those with a mutation at the LQT2 locus (46 percent) or those with a mutation at the LQT3 locus (42 percent) (P<0.001 by Fisher's exact test). Multivariate analysis showed that the genetic locus and the QTc, but not sex, were independent predictors of risk. The QTc was an independent predictor of risk among patients with a mutation at the LQT1 locus and those with a mutation at the LQT2 locus but not among those with a mutation at the LQT3 locus, whereas sex was an independent predictor of events only among those with a mutation at the LQT3 locus. CONCLUSIONS: The locus of the causative mutation affects the clinical course of the long-QT syndrome and modulates the effects of the QTc and sex on clinical manifestations. We propose an approach to risk stratification based on these variables.

Natural history of Brugada syndrome: insights for risk stratification and management.

BACKGROUND: Treatment of patients with Brugada syndrome is complicated by the incomplete information on the natural history of the disease related to the small number of cases reported. Furthermore, the value of programmed electrical stimulation (PES) for risk stratification is highly debated. The objective of this study was to search for novel parameters to identify patients at risk of sudden death. METHODS AND RESULTS: Clinical data were collected for 200 patients (152 men, 48 women; age, 41+/-18 years) and stored in a dedicated database. Genetic analysis was performed, and mutations on the SCN5A gene were identified in 28 of 130 probands and in 56 of 121 family members. The life-table method of Kaplan-Meier used to define the cardiac arrest-free interval in patients undergoing PES failed to demonstrate an association between PES inducibility and spontaneous occurrence of ventricular fibrillation. Multivariate Cox regression analysis showed that after adjusting for sex, family history of sudden death, and SCN5A mutations, the combined presence of a spontaneous ST-segment elevation in leads V1 through V3 and the history of syncope identifies subjects at risk of cardiac arrest (HR, 6.4; 95% CI, 1.9 to 21; P<0.002). CONCLUSIONS: The information on the natural history of patients obtained in this study allowed elaboration of a risk-stratification scheme to quantify the risk for sudden cardiac death and to target the use of the implantable cardioverter-defibrillator.

Transaortic Chordal Cutting: Mitral Valve Repair for Obstructive Hypertrophic Cardiomyopathy With Mild Septal Hypertrophy.

BACKGROUND: In severely symptomatic patients with obstructive hypertrophic cardiomyopathy (HCM) and mild septal hypertrophy, mitral valve (MV) abnormalities may play an important role in MV displacement into the left ventricular (LV) outflow tract. Therefore, isolated myectomy may not relieve outflow obstruction and symptoms, and MV replacement is often the surgical alternative. OBJECTIVES: This study sought to assess the clinical and hemodynamic results of cutting thickened secondary MV chordae combined with a shallow septal muscular resection in severely symptomatic patients with obstructive HCM and mild septal hypertrophy. METHODS: Clinical features were compared before surgery and at most recent clinical evaluation in 39 consecutive patients with obstructive HCM. RESULTS: Over a 23 ± 2 months follow-up, New York Heart Association functional class decreased from 2.9 ± 0.5 pre-operatively to 1.1 ± 1.1 post-operatively (p < 0.001), with no patient in class III at most recent evaluation. The resting outflow gradient decreased from 82 ± 43 mm Hg to 9 ± 5 mm Hg (p < 0.001) and septal thickness decreased from 17 ± 1 mm to 14 ± 2 mm (p < 0.001). No patient had MV prolapse or flail and 1 had residual moderate-to-severe MV regurgitation at most recent evaluation. MV geometry before and after surgery was compared with that of 25 consecutive patients with similar clinical profile and septal thickness that underwent isolated myectomy. After adjustment for differences in pre-operative values between the groups, the post-operative anterior MV leaflet-annulus ratio was 17% greater and tenting area 24% smaller in patients with chordal cutting, indicating that MV apparatus had moved to a more normal posterior position within the LV cavity, preventing MV systolic displacement into the outflow tract and outflow obstruction. CONCLUSIONS: This procedure relieves heart failure symptoms, abolishes LV outflow gradient, and avoids MV replacement in patients with obstructive HCM and mild septal thickness.

Association of long QT syndrome loci and cardiac events among patients treated with beta-blockers.

CONTEXT: Data on the efficacy of beta-blockers in the 3 most common genetic long QT syndrome (LQTS) loci are limited. OBJECTIVE: To describe and assess outcome in a large systematically genotyped population of beta-blocker-treated LQTS patients. DESIGN, SETTING, AND PATIENTS: Consecutive LQTS-genotyped patients (n = 335) in Italy treated with beta-blockers for an average of 5 years. MAIN OUTCOME MEASURES: Cardiac events (syncope, ventricular tachycardia/torsades de pointes, cardiac arrest, and sudden cardiac death) while patients received beta-blocker therapy according to genotype. RESULTS: Cardiac events among patients receiving beta-blocker therapy occurred in 19 of 187 (10%) LQT1 patients, 27 of 120 (23%) LQT2 patients, and 9 of 28 (32%) LQT3 patients (P<.001). The risk of cardiac events was higher among LQT2 (adjusted relative risk, 2.81; 95% confidence interval [CI], 1.50-5.27; P =.001) and LQT3 (adjusted relative risk, 4.00; 95% CI, 2.45-8.03; P<.001) patients than among LQT1 patients, suggesting inadequate protection from beta-blocker therapy. Other important predictors of risk were a QT interval corrected for heart rate that was more than 500 ms in patients receiving therapy (adjusted relative risk, 2.01; 95% CI, 1.16-3.51; P =.01) and occurrence of a first cardiac event before the age of 7 years (adjusted RR, 4.34; 95% CI, 2.35-8.03; P<.001). CONCLUSION: Among patients with genetic LQTS treated with beta-blockers, there is a high rate of cardiac events, particularly among patients with LQT2 and LQT3 genotypes.

[Brugada's syndrome: epidemiology, risk stratification, and clinical management]. / La sindrome di Brugada: epidemiologia, stratificazione del rischio e management clinico.

Brugada syndrome is an arrhythmogenic disease, characterized by syncope and sudden cardiac death, with a typical electrocardiographic pattern: right bundle branch block and ST segment elevation in the right precordial leads. Only recently, the first gene causing Brugada syndrome has been demonstrated by the identification of mutations in SCN5A, the gene encoding for the cardiac sodium channel, also responsible for the LQT3 subtype of long QT syndrome. Despite the knowledge on Brugada syndrome has dramatically improved in the recent years, the clinical management is still often empirical and limited by the lack of pharmacological therapies. Therefore, the implantable cardioverter-defibrillator (ICD) is the only life-saving option for high-risk patients. However, life-long implant in young individuals may have a major impact on the quality of life and it is not free from complications. Therefore, the identification of a robust risk stratification algorithm is of outmost importance to limit the use of ICD to the higher risk individuals. Programmed electrical stimulation has been proposed but this approach appears to have a low positive predictive value, thus leading to implants in many asymptomatic patients. Recently, we analyzed data from 200 Brugada syndrome patients, one of the largest groups so far reported, and we showed that the best predictor of cardiac events is the presence of a spontaneous abnormal ECG pattern associated with history of syncope. In the present article we will review the clinical characteristic of Brugada syndrome and point out a possible risk stratification scheme.