Left ventricular outflow tract gradient decrease with non-surgical myocardial reduction improves exercise capacity in patients with hypertrophic obstructive cardiomyopathy

Effects of Mavacamten on Measures of Cardiopulmonary Exercise Testing Beyond Peak Oxygen Consumption: A Secondary Analysis of the EXPLORER-HCM Randomized Trial

Importance

Mavacamten, a cardiac myosin inhibitor, improved peak oxygen uptake (pVO2) in patients with symptomatic obstructive hypertrophic cardiomyopathy (HCM) in the EXPLORER-HCM study. However, the full extent of mavacamten's effects on exercise performance remains unclear.

Objective

To investigate the effect of mavacamten on exercise physiology using cardiopulmonary exercise testing (CPET).

Design, Setting, and Participants

Exploratory analyses of the data from the EXPLORER-HCM study, a randomized, double-blind, placebo-controlled, phase 3 trial that was conducted in 68 cardiovascular centers in 13 countries. In total, 251 patients with symptomatic obstructive HCM were enrolled.

Interventions

Patients were randomly assigned in a 1:1 ratio to mavacamten or placebo.

Main Outcomes and Measures

The following prespecified exploratory cardiovascular and performance parameters were assessed with a standardized treadmill or bicycle ergometer test protocol at baseline and week 30: carbon dioxide output (VCO2), minute ventilation (VE), peak VE/VCO2 ratio, ventilatory efficiency (VE/VCO2 slope), peak respiratory exchange ratio (RER), peak circulatory power, ventilatory power, ventilatory threshold, peak metabolic equivalents (METs), peak exercise time, partial pressure of end-tidal carbon dioxide (PETCO2), and VO2/workload slope.

Results

Two hundred fifty-one patients were enrolled. The mean (SD) age was 58.5 (11.9) years and 59% of patients were male. There were significant improvements with mavacamten vs placebo in the following peak-exercise CPET parameters: peak VE/VCO2 ratio (least squares [LS] mean difference, -2.2; 95% CI, -3.05 to -1.26; P < .001), peak METs (LS mean difference, 0.4; 95% CI, 0.17-0.60; P < .001), peak circulatory power (LS mean difference, 372.9 mL/kg/min × mm Hg; 95% CI, 153.12-592.61; P = .001), and peak PETCO2 (LS mean difference, 2.0 mm Hg; 95% CI, 1.12-2.79; P < .001). Mavacamten also improved peak exercise time compared with placebo (LS mean difference, 0.7 minutes; 95% CI, 0.13-1.24; P = .02). There was a significant improvement in nonpeak-exercise CPET parameters, such as VE/VCO2 slope (LS mean difference, -2.6; 95% CI, -3.58 to -1.52; P < .001) and ventilatory power (LS mean difference, 0.6 mm Hg; 95% CI, 0.29-0.90; P < .001) favoring mavacamten vs placebo.

Conclusions and Relevance

Mavacamten improved a range of CPET parameters beyond pVO2, indicating consistent and broad benefits on maximal exercise capacity. Although improvements in peak-exercise CPET parameters are clinically meaningful, the favorable effects of mavacamten on submaximal exertional tolerance provide further insights into the beneficial impact of mavacamten in patients with obstructive HCM.

Trial Registration

ClinicalTrials.gov Identifier: NCT03470545.

Current therapies for hypertrophic cardiomyopathy: a systematic review and meta-analysis of the literature

AIMS

The aim of this study was to synthesize the evidence on the effect of the current therapies over the pathophysiological and clinical characteristics of patients with hypertrophic cardiomyopathy (HCM).

METHODS AND RESULTS

A systematic review and meta-analysis of 41 studies identified from 1383 retrieved from PubMed, Web of Science, and Cochrane was conducted. Therapies were grouped in pharmacological, invasive and physical exercise. Pharmacological agents had no effect on functional capacity measured by VO2max (1.11 mL/kg/min; 95% CI: -0.04, 2.25, P < 0.05). Invasive septal reduction therapies increased VO2max (+3.2 mL/kg/min; 95% CI: 1.78, 4.60, P < 0.05). Structured physical exercise programmes did not report contraindications and evidenced the highest increases on functional capacity (VO2max + 4.33 mL/kg/min; 95% CI: 0.20, 8.45, P < 0.05). Patients with left ventricular outflow tract (LVOT) obstruction at rest improved their VO2max to a greater extent compared with those without resting LVOT obstruction (2.82 mL/kg/min; 95% CI: 1.97, 3.67 vs. 1.18; 95% CI: 0.62, 1.74, P < 0.05). Peak LVOT gradient was reduced with the three treatment options with the highest reduction observed for invasive therapies. Left ventricular ejection fraction was reduced in pharmacological and invasive procedures. No effect was observed after physical exercise. Symptomatic status improved with the three options and to a greater extent with invasive procedures.

CONCLUSIONS

Invasive septal reduction therapies increase VO2max, improve symptomatic status, and reduce resting and peak LVOT gradient, thus might be considered in obstructive patients. Physical exercise emerges as a coadjuvant therapy, which is safe and associated with benefits on functional capacity. Pharmacological agents improve reported NYHA class, but not functional capacity.

Prognostic Significance of Initial r-Wave in Leads V1 and aVR Before PTSMA in Patients with Hypertrophic Obstructive Cardiomyopathy

Objective

Percutaneous transluminal septal myocardial ablation (PTSMA) is one of the septal reduction therapies without all satisfactory results in hypertrophic obstructive cardiomyopathy (HOCM) patients. Initial r-wave in leads V1 and aVR on the surface electrocardiography is the sign of ventricular septal base depolarization. Whether the initial r-wave in leads V1 and aVR is predictive of good mid-term response to PTSMA in patients with HOCM remains unknown.

Design, Settings, and Participants

Among 546 consecutive patients evaluated in Fuwai Hospital (Beijing, China), we selected HOCM patients who underwent PTSMA. During the 3-year follow-up after PTSMA, primary outcomes included death, surgical myectomy, syncope, and NYHA classification III/IV.

Results

At last, 85 patients were selected, and were assigned to 3 groups based on the presence of initial r-wave in leads V1 and aVR. Through multivariable Cox and Kaplan–Meier method, patients with initial r-wave in both leads V1 and aVR were independently associated with a decreased risk of primary outcomes (HR: 0.112; 95% CI: 0.024 to 0.518; p = 0.005) during 3-years’ follow-up.

Conclusion

The results suggest that the presence of initial r-wave in both leads V1 and aVR on the surface 12-lead ECG is highly predictive of good mid-term response to PTSMA in patients with HOCM.

A modified endocardial radiofrequency ablation approach for hypertrophic obstructive cardiomyopathy guided by transthoracic echocardiography: a case series

Background

A series of studies showed that endocardial radiofrequency ablation (ERFA) could reduce the left ventricular outflow tract (LVOT) gradient in patients with septal hypertrophy. This study aimed to determine the safety and efficacy of a modified ERFA approach guided by transthoracic echocardiography (TTE) as an alternative to ablation performed under a three-dimensional (3D) electroanatomical system or intracardiac echocardiography (ICE).

Methods

Twenty-five patients with hypertrophic obstructive cardiomyopathy (HOCM) underwent ERFA of septal hypertrophy, guided by echocardiography. The LVOT gradient, left ventricular ejection fraction (LVEF), LV thickness, New York Heart Association (NYHA) class, and biochemical laboratory values were recorded before ablation and during follow-up.

Results

The patients’ peak and stress-induced LVOT gradients were significantly reduced after 12 months of follow-up (resting gradient: from 123.2±17.7 to 15.7±7.8 mmHg, P<0.05; provocative gradient: from 140.2±20.8 to 18.4±8.0 mmHg, P<0.05). Compared with baseline, the septal diameter was reduced slightly after 12 months, but the difference was not significant (24.8±3.5 vs. 24.2±3.4 mm, P>0.05). The reduction in LVOT gradient was associated with an improvement in NYHA functional classification (from 3.0±0.0 to 1.6±0.7, P<0.05), the 6-minute walking distance (413±129 m at baseline; 458±108 m immediately after ERFA; 471±139 m after 12 months, P<0.05), and pro B-type natriuretic peptide levels (from 924.00±139 to 137.45 ±75.73 pg/mL, P<0.05). After the procedure, the patients showed no worsening of LVEF compared with baseline (64%±5.3%), and no cases of bundle branch block nor complete heart block occurred.

Conclusions

ERFA guided by TTE provides a new treatment option for HOCM which can achieve symptomatic improvement as well as a significant and sustained reduction of the LVOT gradient. Moreover, by avoiding the use of the 3D electroanatomical system or ICE, this treatment has an acceptable cost.

Transcatheter septal ablation in hypertrophic obstructive cardiomyopathy: a technical guide and review of published results

Transcatheter alcohol septal ablation (ASA) treatment of symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM) is based on the existence and degree of intraventricular obstruction. Patients with significant gradient and symptoms who do not respond to optimal medical therapy are eligible to gradient reduction through a surgical (septal myectomy) or a transcatheter (alcohol septal ablation) septal reduction. The latter encompasses occlusion of a septal branch perfusing the hypertrophied septum, which is involved in the generation of obstruction, by injecting ethanol into the supplying septal branch(es). ASA has been established as a highly effective and safe method and has outnumbered the surgical gold standard. Although the technique is straightforward, patient selection and some technical details may influence the efficacy and safety of the procedure. The technique is based on echocardiographic contrast guidance, which allows accurate target septal branch selection and optimisation of the result. Published long-term results from high-volume centres have confirmed the effectiveness of ASA and have shown excellent survival, which is comparable to that in the general population. Choice and performance of the surgical or interventional treatment should be implemented in highly specialised centres in terms of a heart-team approach, taking notice of anatomic characteristics as well as comorbidities. Involvement of all cases in international registries may reveal the individual merits and indications for the surgical and interventional treatment in HOCM.

Hypertrophic Obstructive Cardiomyopathy: Surgical Myectomy and Septal Ablation

Hypertrophic cardiomyopathy is a genetic disorder characterized by marked hypertrophy of the myocardium. It is frequently accompanied by dynamic left ventricular outflow tract obstruction and symptoms of dyspnea, angina, and syncope. The initial therapy for symptomatic patients with obstruction is medical therapy with β-blockers and calcium antagonists. However, there remain a subset of patients who have continued severe symptoms, which are unresponsive to medical therapy. These patients can be treated with septal reduction therapy, either surgical septal myectomy or alcohol septal ablation. When performed by experienced operators working in high-volume centers, septal myectomy is highly effective with a >90% relief of obstruction and improvement in symptoms. The perioperative mortality rate for isolated septal myectomy in most centers is <1%. Alcohol septal ablation is a less invasive treatment. In many patients, the hemodynamic and clinical results are comparable to that of septal myectomy. However, the results of alcohol septal ablation are dependent on the septal perforator artery supplying the area of the contact between the hypertrophied septum and the anterior leaflet of the mitral valve. There are some patients, particularly younger patients with severe hypertrophy, who do not uniformly experience complete relief of obstruction and symptoms. Both techniques of septal reduction therapy are highly operator dependent. The final decision as to which approach should be selected in any given patient is dependent up patient preference and the availability and experience of the operator and institution at which the patient is being treated.

Twenty Years of Alcohol Septal Ablation in Hypertrophic Obstructive Cardiomyopathy

Hypertrophic obstructive cardiomyopathy is the most common genetic cardiac disease and is generally characterised by asymmetric septal hypertrophy and intraventricular obstruction. Patients with severe obstruction and significant symptoms that persist despite optimal medical treatment are candidates for an invasive septal reduction therapy. Twenty years after its introduction, percutaneous transluminal alcohol septal ablation has been increasingly preferred for septal reduction in patients with drug refractory hypertrophic obstructive cardiomyopathy. Myocardial contrast echocardiography and injection of reduced alcohol volumes have increased safety, while efficacy is comparable to the surgical alternative, septal myectomy, which has for decades been regarded as the 'gold standard' treatment. Data on medium- and long-term survival show improved prognosis with survival being similar to the general population. Current guidelines have supported its use by experienced operators in centres specialised in the treatment of patients with hypertrophic obstructive cardiomyopathy.

Cardiopulmonary Exercise Testing and Prognosis in Hypertrophic Cardiomyopathy

Background—

Exercise testing is performed in patients with hypertrophic cardiomyopathy to evaluate blood pressure response, a risk factor for sudden cardiac death. The prognostic role of exercise gas exchange variables is unknown.

Methods and Results—

Between 1998 and 2010, 1898 patients (age 47±15 years, range 16–86 years; 67% male) with hypertrophic cardiomyopathy underwent cardiopulmonary exercise testing. A total of 178 (9.4%) patients reached the primary end point of all-cause mortality or heart transplant (death/transplant) during a median follow-up of 5.6 years (interquartile range 2.6–8.9), giving an annual event rate of 1.6% per person year. Peak oxygen consumption (adjusted hazard ratio [HR] 0.82, 95% confidence interval [CI] 0.77–0.88, P <0.001), ventilatory efficiency (adjusted HR 1.10, 95% CI 1.00–1.22, P =0.049), and ventilatory anaerobic threshold (adjusted HR 0.82, 95% CI 0.70–0.96, P =0.016) were predictors of the primary outcome after correction for age, sex, left atrial size, nonsustained ventricular tachycardia, and ejection fraction. The overall adjusted death/transplant estimates for patients in the lowest quartile with peak oxygen consumption ≤15.3 mL/kg/min were 14% at 5 years and 31% at 10 years. Peak oxygen consumption (HR 0.81, 95% CI 0.77–0.86, P <0.01) and ventilation to carbon dioxide production (HR 1.10, 95% CI 1.08–1.13, P <0.001) were predictors of death because of heart failure or transplantation but not sudden cardiac death or implantable cardioverter defibrillator shocks.

Conclusions—

Cardiopulmonary exercise testing provides prognostic information in patients with hypertrophic cardiomyopathy. Submaximal exercise parameters, such as ventilatory efficiency and anaerobic threshold, measured alone or in combination with peak oxygen consumption, predict death from heart failure.

Alcohol septal ablation for hypertrophic obstructive cardiomyopathy - 8 years follow up

Background

Alcohol septal ablation is emerging as an alternative to surgical myectomy in the management of symptomatic cases of Hypertrophic obstructive cardiomyopathy (HOCM). This involves injection of absolute alcohol into 1st septal perforator thereby producing myocardial necrosis with resultant septal remodelling within 3–6 months. This results in reduction of septal thickness and LV outflow gradients with improvement in symptoms.

Methods

Fifty three patients had undergone alcohol septal ablation, there were 2 early and 2 late deaths and 4 patients lost to follow up. Forty-five (85%) of them were followed up to a mean period of 96 ± 9.2 months. Clinical, ECG, and Echocardiographic parameters were evaluated during follow up.

Results

Only 4 out of 51 patients remained in NYHA class III or IV at the end of 6 months. Significant reduction of LV outflow gradients (79 ± 35 to 34 ± 23 mmHg) and septal thickness (23 ± 4.7 mm to 19 ± 3 mm) were observed during 6 months follow up. Beyond 6 months there was no further decrease in either septal thickness or LVOT gradients noted. Ten percent of patients needed pacemaker implantation. There was 92% survival at the end of 8 years.

Conclusion

Alcohol septal ablation is a safe and effective nonsurgical procedure for the treatment of HOCM. By minimizing the amount of alcohol to ≤2 ml, one can reduce complications and mortality. The long-term survival is gratifying.

Cardiac MRI detected septal and lateral myocardial infarction by alcohol septal ablation through the intermediate artery

A 65-year-old woman with hypertrophic obstructive cardiomyopathy presented with dyspnea. Transthoracic echocardiography showed severe mitral regurgitation (MR) due to systolic anterior motion and a peak gradient of 102 mmHg across the LV outflow. Cardiac magnetic resonance imaging (CMR) showed patchy late gadolinium enhancement in the hypertrophied septum. Because of non-responsiveness to medical treatment, percutaneous alcohol septal ablation (ASA) was conducted. The septal perforator that supplied the hypertrophic myocardium originated from the intermediate artery. A 2.0-mm over-the-wire balloon was used to occlude the intermediate artery and 1.1 ml of ethanol was injected slowly into the target septal perforator branch. The gradient decreased markedly to 5 mmHg immediately after ASA, and electrocardiogram showed right bundle branch block. Echocardiographic findings at 1 week were satisfactory. However, CMR showed delayed enhancement in both the hypertrophic basal septum and the lateral wall. The clinical course was uneventful, and she has maintained NHYA functional class 1 so far. In this case, proximal migration of the balloon or an undersized occluding balloon may have caused lateral infarction through leakage of ethanol into another branch. CMR is a useful modality to verify whether the ASA procedure has induced the appropriate controlled infarction.

A decade of percutaneous septal ablation in hypertrophic cardiomyopathy

Percutaneous septal ablation has emerged as a less invasive treatment of symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM). In the past decade, the availability of this sophisticated technique has revived the interest of cardiologists in left ventricular outflow tract obstruction, which led to the recognition that most patients with HCM have the obstructive type. Follow-up studies have already shown the safety and efficacy of the procedure, which offers symptomatic relief in most patients. Long-term survival is comparable to historical reports after surgical myectomy. Complications are rare and can be further reduced with increased experience of the operators, and the theoretical concern for possible ventricular arrhythmogenicity of the myocardial scar has not been documented by the existing data. Although there are still no randomized trials, percutaneous septal ablation is undeniably a viable alternative for patients with HOCM.

Descriptive anatomy of the dominant septal perforators using Dual Source Coronary CT Angiography

Although clinical outcomes for septal ablation in treating left ventricular outflow tract obstructions are generally favorable, a variety of complications have been reported including a high incidence of right bundle branch block. These complications may be attributed to anatomic variability of the dominant septal perforator. We used Dual Source CT Coronary Angiography (DS-CTA) to determine the location of the termination point of the dominant septal perforator as well as the distance of the termination point from the mitral annulus in patients undergoing DS-CTA. One-hundred-fourteen DS-CTA scans were retrospectively reviewed by two observers by consensus. The left ventricle was divided into anterior wall, anterioseptum, and inferioseptum. For each segment, the myocardium was divided into three layers (1) right ventricular side, (2) mid portion, and (3) left ventricular side. The zone of termination of the dominant septal perforator was identified as well as the distance of the termination point from the mitral annulus. The dominant septal perforator terminated in the right ventricular side of the anterioseptum in 86 of the 118 visualized terminations (73%) and in the left ventricular anterior wall in 6 visualized terminations (5%). On average, the dominant septal perforator terminated 26.3 +/- 8.6 mm from the mitral annulus. In the majority of cases, the dominant septal perforator terminates in the right ventricular side of anterioseptum. In addition, there is great variability in the distribution of the termination point of the dominant septal perforator from the mitral annulus.

[Evolution of the surgical strategy in hypertrophic cardiomyopathy: case studies of eight patients]

INTRODUCTION

Hypertrophic cardiomyopathy is an inherited disease characterized by a left ventricular hypertrophy, a diastolic dysfunction and rhythm troubles with risk of sudden death. There was an evolution in the surgical strategy to treat the patients who present a left ventricular outflow tract gradient.

MATERIALS AND METHODS

A retrospective study was conducted: We selected eight cases who presented an hypertrophic cardiomyopathy and operated on. Pre and post operative echocardiographic data were analysed. Follow up was obtained by call or mail to the cardiologist.

RESULTS

The patients were classified in four groups: isolated left ventricular outflow tract obstruction, left ventricular outflow tract obstruction and associated lesions, obstructive hypertrophic cardiomyopathy and endocarditis, post operative complications of the hypertrophic cardiomyopathy surgery. We observed a significant decrease of the left ventricular outflow tract mean gradient in the post operative period and at four years.

CONCLUSION

Surgical management of obstructive hypertrophic cardiomyopathy remain an important option in young patients, in case of failure of the ethanol septal ablation or in patients who present other surgical lesions. The dual chamber stimulation remain indicated in old patients.

Alcohol septal ablation for hypertrophic obstructive cardiomyopathy: a systematic review of published studies

OBJECTIVE

Alcohol septal ablation (ASA) for hypertrophic obstructive cardiomyopathy (HOCM) has emerged as a lesser invasive alternative to surgical myectomy over the past decade. The purpose of this study is to analyze all the published literature on outcomes and complications after ASA.

METHODS

MEDLINE and PubMed were searched for all available published literature on ASA (June 1996-June 2005) using the terms hypertrophic obstructive cardiomyopathy (HOCM), alcohol septal ablation for hypertrophic obstructive cardiomyopathy, alcohol septal ablation for HOCM, alcohol septal ablation (ASA), transcoronary alcohol septal ablation for hypertrophic obstructive cardiomyopathy (TASH), transcoronary alcohol septal ablation for HOCM, nonsurgical septal reduction therapy (NSRT), and percutaneous transcoronary septal myocardial ablation (PTSMA).

RESULTS

A total of 42 published studies (2,959 patients) were analyzed. Mean age was 53.5 (35.4-72) years with a mean male to female ratio of 1.17. Mean follow-up was 12.7 +/- 0.3 months (1.5-43.2). Absolute ethanol (3 mL) was injected in 1.2 septal perforator arteries. On average, serum CK peaked at 964 units. At 12 months, there was a sustained decrease in resting and provoked LVOT gradient (65.3-15.8 and 125.4-31.5 mmHg, respectively) accompanied by reduction in basal septal diameter (20.9-13.9 mm), improvement in NYHA Class (2.9-1.2), and increase in exercise capacity (325.3-437.5 seconds). Early mortality (within 30 days) was 1.5% (0.0-5.0%) and late mortality (beyond 30 days) was 0.5% (0.0-9.3%). Other complications include ventricular fibrillation (2.2%), LAD dissection (1.8%), complete heart block requiring permanent pacemaker (10.5%), and pericardial effusion (0.6%). A repeat ASA was performed on 6.6% of patients and 1.9% of patients underwent surgical myomectomy with resolution of symptoms.

CONCLUSIONS

Literature to date suggests that ASA results in acute and intermediate-term favorable clinical and echocardiographic outcomes. A randomized controlled trial is needed to compare ASA and myomectomy in order to determine which technique provides maximal benefit.

Effects of varying ethanol dosing in percutaneous septal ablation for obstructive hypertrophic cardiomyopathy on early hemodynamic changes

This prospective, randomized study evaluates the association between ethanol dose and postprocedural hemodynamic changes in 42 patients treated by alcohol septal ablation for obstructive hypertrophic cardiomyopathy. These results suggest that the early course of hemodynamic changes is not related to the use of a small (1 to 2 ml) or standard (>2 ml) dose of ethanol.

Apical myocardial injury caused by collateralisation of a septal artery during ethanol septal ablation

In patients who are refractory to medical treatment of hypertrophic cardiomyopathy, surgical myomectomy or percutaneous transluminal alcohol septal myocardial ablation (PTSMA) is appropriate, with both the procedures having comparable results. In PTSMA ethanol is selectively injected into septal arteries supplying the hypertrophied septal myocardium. The authors describe a case of apical myocardial injury caused by passage of ethanol into the distal left anterior descending artery through a septal collateral that developed after double bolus injection of ethanol. They advocate single bolus injection of alcohol to avoid this complication.

Alcohol septal ablation for hypertrophic obstructive cardiomyopathy: Lower alcohol dose reduces size of infarction and has comparable hemodynamic and clinical outcome

Patients with highly symptomatic hypertrophic obstructive cardiomyopathy (HOCM) are considered to be good candidates for percutaneous transluminal septal myocardial ablation (PTSMA). However, there is ongoing discussion regarding the optimal dose of alcohol injected into target septal artery and the impact of infarct sizes on the clinical and hemodynamic outcome. Thirty-four patients with symptomatic HOCM receiving maximum medical therapy were consecutively enrolled. Patients were randomized in a 1:1 ratio into one of the two arms according to dose of injected alcohol during echocardiography-guided PTSMA procedure. Clinical, electrocardiographic, and echocardiographic evaluation were performed 6 months after the procedure in all the patients. Both groups of patients matched in all clinical and echocardiographic data. The dose of alcohol injected was 1.6 +/- 0.4 and 3.4 +/- 0.9 (P < 0.001) with subsequent peak of CK-MB 1.9 and 3.2 microkat/L (P < 0.05) in group A and B, respectively. There was a correlation between amount of injected alcohol and the peak of CK-MB (r = 0.58; P < 0.01), whereas no significant relationship (r = 0.16; P = NS) was documented between the peak of CK-MB and left ventricular outflow gradient at follow-up. At 6-month follow-up, both groups of patients were not significantly different with regard to symptoms or electrocardiographic and echocardiographic findings. In conclusion, this study suggests that the low dose (1- 2 ml) of alcohol injected into target septal branch reduces size of necrosis. Moreover, the low dose is probably as safe and efficacious as usually used doses (2-4 ml).

Comparison of dual-chamber pacing with nonsurgical septal reduction effect in patients with hypertrophic obstructive cardiomyopathy

OBJECTIVES

The aim of the study was to compare the influence of dual-chamber pacing vs. nonsurgical septal reduction on hemodynamic and morphological parameters in patients with obstructive form of hypertrophic cardiomyopathy.

METHODS

Nineteen patients with dual-chamber pacing (group I) and 9 patients who underwent nonsurgical septal reduction (group II) were studied at baseline and after a 6-month follow-up. The changes of left ventricular outflow tract gradient and posterior wall thickness (as an index of left ventricular hypertrophy regression) were compared.

RESULTS

The baseline left ventricular outflow tract gradient was comparable between group I and group II (77+/-25 vs. 82+/-25 mm Hg, p>0.05). At 6-month follow-up, the left ventricular outflow tract gradient was reduced to a similar level in both groups (28+/-19 vs. 25+/-12 mm Hg, p>0.05). At baseline, posterior wall hypertrophy was comparable between groups (12.9+/-1.7 vs. 13.6+/-2.2 mm, p>0.05). During follow-up, the posterior wall thickness was unchanged in the pacing group (12.9+/-1.7 vs. 12.6+/-1.6 mm, p>0.05), whereas nonsurgical septal reduction induced regression of left ventricular hypertrophy in myocardial region remote from the infarcted septal segment (13.6+/-2.2 vs. 10.5+/-2.3 mm, p<0.003).

CONCLUSION

Despite comparable reduction of instantaneous left ventricular outflow tract gradient, the nonsurgical septal reduction decreased posterior wall thickness, whereas pacing did not reduce left ventricular hypertrophy. Thus, regression of left ventricular hypertrophy that appeared solely after nonsurgical septal reduction may reflect the more permanent reduction of left ventricular pressure overload. Thus, not only hemodynamic but also morphological benefit from nonsurgical septal reduction seems to indicate the superiority of this method over dual-chamber pacing.

Miocardiopatía hipertrófica en el adulto. Curso clínico y factores pronósticos de 119 pacientes

BACKGROUND AND OBJECTIVE

The purpose of this study was to characterize adult patients with hypertrophic cardiomyopathy (HCM), to compare their mortality with that of the general population and to establish a prognosis based on clinical and noninvasive techniques.

PATIENTS AND METHOD

One hundred nineteen consecutive patients (60 women, mean: 52 [12] years) with HCM were prospectively studied by ECG, Holter, echo-Doppler, exercise testing, myocardial perfusion SPET and radionuclide ventriculography. Prognostic variables included clinical data and parameters derived from these noninvasive techniques.

RESULTS

During a mean follow-up of 10 [6.7] years, 7 patients (5.8%) died of cardiovascular causes (4 cardiac failure and 3 sudden death). The annual mortality rate was 0.6% and the actuarial survival curve for patients with HCM was significantly worse compared with the expected survival curve derived from the general population after adjustment for age and sex (p = 0.008). The presence of atrial fibrillation (p = 0.04), moderate or severe mitral regurgitation (p = 0.02), dynamic gradient > 50 mmHg (p = 0.02), left atrial diameter > 45 mm (p = 0.02), and interventricular septal thickness > 25 mm (p = 0.04) were all predictive of mortality.

CONCLUSIONS

The mortality rate of adult patients with HCM is significantly higher than that expected for the general population and heart failure and sudden death are almost evenly distributed as a cause of death in these patients. Atrial fibrillation, magnitude of mitral regurgitation, dynamic gradient, left atrial dilatation and interventricular septal thickness are the main predictors of death.

Percutaneous transluminal septal myocardial ablation for hypertrophic obstructive cardiomyopathy

Percutaneous transluminal septal myocardial ablation (PTSMA) is a new therapeutic option for patients with hypertrophic obstructive cardiomyopathy (HOCM). In the present study, the acute and follow-up results of PTSMA were evaluated. From August 1997 to March 2003 27 medically refractory patients (New York Heart Association (NYHA) functional class 2.9+/-0.6) with HOCM underwent PTSMA. The target septal branch was determined by probationary ballooning in 3 and by myocardial contrast echocardiography in 24 patients. The mean resting left ventricular outflow tract pressure gradient (PG) was reduced from 70+/-44 to 24+/-22 mmHg (p<0.0001); the peak concentration of creatine kinase was 1545+/-686 IU/L. Although transient trifascicular block was observed in 14 patients, permanent pacemaker implantation was not required. There were no major adverse cardiac events during the hospital stay; the mean clinical follow-up was 2.2+/-1.7 years. Repeated PTSMA was needed in 1 patient; however, symptomatic improvement had been well preserved in all patients (NYHA class 1.2+/-0.4). Follow-up echocardiographic examination showed sustained improvement in PG, septal and left ventricular posterior wall thicknesses, and the grade of systolic anterior movement and regurgitation of the mitral valve. In conclusion, PTSMA is a safe and effective therapeutic option for medically refractory patients with HOCM.

Early remodelling of left ventricle and improvement of myocardial performance in patients after percutaneous transluminal septal myocardial ablation for hypertrophic obstructive cardiomyopathy

BACKGROUND

Percutaneous transluminal septal myocardial ablation (PTSMA) reduces left ventricular outflow (LVOT) gradient in patients with hypertrophic obstructive cardiomyopathy (HOCM) and leads to symptomatic improvement. Effects of PTSMA on left ventricular performance are currently unknown. The purpose of this study was to evaluate changes in the left ventricular performance using Doppler index of myocardial performance (sum of isovolumic contractile and relaxation times divided by left ventricular ejection time) and left ventricular remodelling after PTSMA for HOCM.

METHODS

Twenty-five patients with symptomatic HOCM underwent echocardiography-guided PTSMA procedure. Clinical and echocardiographic data were collected at baseline and 3 months after PTSMA.

RESULTS

PTSMA procedures were uneventful, in one patient (4%), pacemaker implantation was needed for sustained complete heart block after the procedure. At 3-month follow-up, the maximal LVOT gradient decreased from 68+/-39 to 18.6+/-12 mmHg (P<0.001), the provoked maximal LVOT gradient decreased from 128.8+/-59 to 25+/-21.4 mmHg (P<0.001), and basal septal thickness decreased from 21.7+/-4 to 15.2+/-3 mm (P<0.001). The improvement of the index of myocardial performance (from 0.65+/-7 to 0.56+/-11; P<0.001) was associated with neither significant change in left ventricular ejection fraction nor left ventricular ejection time. There was no significant difference in the left ventricular dimension at baseline and at follow-up. All patients reported a significant improvement in symptoms at follow-up, the mean NYHA class decreased from 2.6+/-0.7 to 1.4+/-0.7 (P<0.001), and the number of patients suffering from episodes of syncope or attacks of dizziness decreased from 13 to two during the 3-month follow-up.

CONCLUSIONS

PTSMA is a safe, effective and reproducible method in the treatment of highly symptomatic patients with HOCM. This procedure results in a significant relief of symptoms associated with decrease in LVOT gradient and thickness of basal interventricular septum. Positive changes in Doppler IMP suggest possible improvement of left ventricular function.

Current status of alcohol septal ablation for patients with hypertrophic cardiomyopathy

Since the early 1960s, surgical myotomy-myectomy has been the standard treatment for patients with drug-refractory symptoms due to hypertrophic cardiomyopathy and dynamic outflow tract obstruction. Comparable morphologic and functional results can be achieved by percutaneous septal ablation (PTSMA) by alcohol-induced septal branch occlusion. The circumscribed therapeutic myocardial infarction results in widening of the left ventricular outflow tract with consecutive gradient reduction. Follow-up studies show clinical and objective improvement as well as further gradient reduction due to left ventricular remodeling. In this article, an updated review of the latest results of PTSMA is provided.

Value of exercise testing in assessing clinical state and prognosis in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetic disease of the sarcomeric contractile proteins. A majority of patients with HCM are limited in terms of functional capacity, and a minority of these patients die suddenly. The main aims of management are symptom alleviation and prevention of sudden cardiac death. In patients with HCM, cardiopulmonary exercise testing provides a much more accurate index of functional capacity than New York Heart Association classification status, and it is useful in assessing symptoms after various therapeutic strategies have been implemented. Exercise testing is also valuable in identifying patients with HCM who are at high risk of sudden cardiac death and is an integral part of the algorithm in risk stratification and delivery of prophylactic therapy. Also, cardiopulmonary exercise testing plays an important role in differentiating HCM from other conditions associated with left ventricular hypertrophy, such as physiologic athlete's heart. Therefore, during the last few years, cardiopulmonary exercise testing has provided insights into the diagnosis, determinants, and mechanisms of exercise limitation in HCM. This understanding aids physicians in targeting therapy and developing new treatment modalities.

The role of exercise testing in the evaluation of the patient with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetic disease of the sarcomeric contractile proteins that is characterized by left ventricular hypertrophy and myocyte disarray. The majority of patients are limited in terms of functional capacity and a minority die suddenly. The main aims of management are symptom alleviation and prevention of sudden cardiac death. In patients with HCM, cardiopulmonary exercise testing provides a more accurate index of functional capacity than New York Heart Association classification status and is useful in assessing symptoms following various therapeutic interventions. Cardiopulmonary exercise testing plays an important role in differentiating HCM from other conditions associated with left ventricular hypertrophy. Cardiopulmonary exercise testing is also valuable in identifying individuals at high risk of sudden cardiac death and is an integral part of the algorithm in risk stratification and delivery of prophylactic therapy. Over the past few years, cardiopulmonary exercise testing has provided insight into the determinants and mechanisms of exercise limitation. This understanding helps in targeting therapy and the development of new treatment modalities.

Percutaneous transluminal septal myocardial ablation: A new catheter-based therapy for patients with hypertrophic obstructive cardiomyopathy

Hypertrophic obstructive cardiomyopathy is a complex disorder with serious clinical implications. Percutaneous transluminal septal myocardial ablation is a promising new addition to existing therapies for this condition. It is a catheter-based approach that involves instilling alcohol into the septal branches of the left anterior descending artery to induce a 'controlled' septal myocardial infarct. The result is a decrease in thickness of the hypertrophied interventricular septum and a reduction of the left ventricular outflow tract gradient. To date, the results from several series have been promising, with improvements in haemodynamic and clinical parameters without prohibitive complication rates. In this article, the indications, technique and outcomes of this procedure are reviewed.