Percutaneous transluminal septal ablation in hypertrophic obstructive cardiomyopathy

Looking back on 15 years of ultrasound-guided alcohol septal ablation for hypertrophic obstructive cardiomyopathy

Background: Septal reduction remains an important target of current therapeutic modalities in hypertrophic obstructive cardiomyopathy (HOCM). Surgical septal myectomy has long been considered the gold standard in pharmacotherapy-refractory severely symptomatic patients with marked left ventricular outflow tract (LVOT) obstruction. In recent years, percutaneous alcohol septal ablation (ASA) has matured into the preferred strategy for patients with favourable anatomy and no other coexisting surgically amenable disease.Methods: We discuss 26 HOCM patients with persistent dyspnoea, angina or syncope despite optimal medical treatment. Baseline septal wall thickness was 20 ± 3 mm, with peak resting/provoked LVOT gradients of 53 ± 35/112 ± 40 mmHg. Guided by echocardiography, alcohol injection could be restricted to the first septal coronary artery in 85% of patients, provoking basal septal infarction with average troponin rise of 3.0 ng/ml.Results: Eighty-six per cent of patients experienced sustained clinical improvement, associated with a reduction of septal wall thickness to 15 ± 3 mm and resting LVOT gradient to 21 ± 15 mmHg. One of the two non-responders underwent additional septal myectomy 11 years after ASA. Notable adverse events during the follow-up of 7.2 ± 4.7 years included: persistent conduction disturbances (65%) necessitating early postprocedural permanent pacemaker implantation (15%); atrial fibrillation (32%); ventricular tachycardia (4%) and aortic stenosis (14%). Six patients died, of which only 1 cardiac death.Conclusions: Our case series underscores the efficacy of ASA at relieving LVOT obstruction and improving symptoms in properly selected HOCM patients, with acceptably low procedural and long term mortality and morbidity.

Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disease. The disease is characterized by marked variability in morphological expression and natural history, ranging from asymptomatic to heart failure or sudden cardiac death. Left ventricular hypertrophy and abnormal ventricular configuration result in dynamic left ventricular outflow obstruction in most patients. The goal of pharmacological therapy in HCM is to alleviate the symptoms, and it includes pharmacotherapies and septal reduction therapies. In this review, we summarize the relevant clinical issues and treatment options of HCM.

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.

Percutaneous transluminal radiofrequency closure of the coronary artery in animal studies

The aim of this study was to investigate the safety and effectiveness of a novel method for the selective transcoronary closure of small coronary arteries by the intraluminal application of radiofrequency (RF) energy. Twenty-six small (diameter of 1–2 mm) coronary artery branches were selected in 13 dogs. An RF electrode wire (CRW-Zcy) was placed into the target vessel and a coronary balloon was used to transiently block the blood flow and limit damage to the proximal vessel. A therapeutic dosage of 20–30 W of RT energy every 10–30 sec (selected according the diameter of the target artery) was discharged via the CRW-Zcy inside a microcatheter two or three times in order to achieve arterial closure. A high dosage of 60 W every 120 sec of RF energy was used to conduct the safety study. All 26 branches were successfully closed resulting in the complete blockage of the antegrade and retrograde flows. The area of injury was limited to the target artery and the supplied myocardium. High-dose RF did not cause injury to the adjacent vessels and myocardium. The animals tolerated the procedure well without any untoward systemic effects. A follow-up angiography at two weeks revealed no evidence of recanalization or retrograde filling of the target artery. Percutaneous transluminal radiofrequency closure is a safe and effective interventional approach for closing the small coronary arteries, and is potentially valuable for further investigation.

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.

Visualization of transcoronary ablation of septal hypertrophy in patients with hypertrophic obstructive cardiomyopathy: a comparison between cardiac MRI, invasive measurements and echocardiography

Objective

Hypertrophic obstructive cardiomyopathy (HOCM) is treated by surgical myectomy or transcoronary ablation of septal hypertrophy (TASH). The aim of this study was to visualize the feasibility, success and short-term results of TASH on the basis of cardiac MRI (CMR) in comparison with cardiac catheterization and echocardiography.

Methods

In this in vivo study, nine patients with HOCM were treated with TASH. Patients were evaluated by transthoracic echocardiography, invasive cardiac angiography and CMR. Follow-up examinations were carried out after 1, 3 and 12 months. MR imaging was performed on a 1.5-T scanner. All images were processed using the semiautomatic Argus software and were evaluated by an attending thoracic radiologist and cardiologist.

Results

The echocardiographic pressure gradient (at rest) was 69.3 ± 15.3 mmHg before and 22.1 ± 5.7 mmHg after TASH (P < 0.01, n = 9). The flux acceleration over the aortic valve examined (V_max) was 5.1 ± 0.6 m/s before and 3.4 ± 0.3 m/s after the TASH procedure (P < 0.05). Also, there was a decrease of septum thickness from 22.0 ± 1.2 to 20.2 ± 1.0 mm (P < 0.05) after 6 ± 3 weeks. The invasively assessed pressure gradient at rest was reduced from 63.7 ± 15.2 to 21.2 ± 11.1 mmHg (P < 0.01) and the post-extrasystolic gradient was reduced from 138.9 ± 12.7 to 45.6 ± 16.5 mmHg (P < 0.01). All differences as well as the quantity of injected ethanol were plotted against the size or amount of scar tissue as assessed in the MRI. There was a statistically significant correlation between the post-extrasystolic gradient decrease and the amount of scar tissue (P = 0.03, r² = 0.5). In addition, the correlation between the quantity of ethanol and scar tissue area was highly significant (P < 0.01, r² = 0.6), whereas the values for the gradient deviation (P = 0.10, r² = 0.34), ΔV_max (P = 0.12, r² = 0.31), as well as the gradient at rest (P = 0.27, r² = 0.17) were not significant.

Conclusion

TASH was consistently effective in reducing the gradient in all patients with HOCM. In contrast to the variables investigated by echocardiography, the invasively measured post-extrasystolic gradient correlated much better with the amount of scar tissue as assessed by CMR. We conclude that the optimal modality to visualize the TASH effect seems to be a combination of CMR and the invasive identification of the post-extrasystolic gradient.

[The role of real-time three-dimensional echocardiography in the evaluation of hypertrophic cardiomyopathy]

Hypertrophic cardiomyopathy is a relatively common hereditary disorder, which is associated with cardiac morphologic and functional alterations. Echocardiography is a non-invasive, simple and easy-to-learn method to evaluate patients with cardiomyopathy. The aim of this review paper is to demonstrate the possible diagnostic role of one of the newest echocardiographic development, the real-time 3-dimensional echocardiography in the evaluation of hypertrophic cardiomyopathy.

Usefulness of clinical, echocardiographic, and procedural characteristics to predict outcome after percutaneous transluminal septal myocardial ablation

This study was conducted to assess outcomes after percutaneous transluminal septal myocardial ablation (PTSMA) treatment in 131 patients (mean age 56+/-16 years) with obstructive hypertrophic cardiomyopathy. In-hospital and follow-up complications as well as late PTSMA failure (defined as unsatisfactory clinical outcome and a significant residual outflow tract gradient, necessitating reintervention) were noted. Baseline clinical, echocardiographic, and PTSMA characteristics were examined as determinants of outcomes. Also, the effect of ethanol volume and the role of a learning curve were investigated. PTSMA was successful in 90% of the patients. In-hospital and follow-up cardiac events were noted in 20 patients, including cardiac death (in-hospital n=4, follow-up n=1), acute myocardial infarction due to ethanol leakage (n=1), coronary dissection (n=2), nonfatal cardiac tamponade (n=1), and permanent pacemaker (n=6) or cardiac defibrillator (in-hospital n=4, follow-up n=1) implantation. Late PTSMA failure was noted in 12 patients. All baseline characteristics were comparable between successful and failed PTSMA. Ethanol volume was related to peak creatinine kinase value (p<0.0001) but not to late PTSMA failure or greater need for pacemaker implantation. Late PTSMA failure occurred more frequently in PTSMA procedures performed in the early, less experienced time period (p<0.001). In conclusion, this study confirms that PTSMA, although effective, has a relatively high complication rate. Late PTSMA failure could not be predicted by baseline characteristics but could partially be explained by a learning-curve effect. This finding implies that PTSMA procedures should be restricted to experienced centers.

Treatment modalities in hypertrophic obstructive cardiomyopathy: surgical myectomy versus percutaneous septal ablation

BACKGROUND

The aim of this study was to compare the results of percutaneous septal myocardial ablation (PSMA) and surgical myectomy (SM) for decreasing the left ventricular outflow tract (LVOT) gradient, septal thickness, ventricular dimensions, and mitral regurgitation (MR) in patients with symptomatic hypertrophic obstructive cardiomyopathy.

METHODS

We treated 40 patients (mean age, 24.4 +/- 6.8 years; 34 male and 6 female patients) between June 2002 and April 2006. Twenty-four patients underwent SM, and 16 patients underwent PSMA. All patients were symptomatic despite maximal medical treatment and had an LVOT gradient higher than 65 mm Hg. Their echocardiographic data were recorded before and after the procedure and then compared. The patients were followed up postoperatively for a mean of 13 months.

RESULTS

There was no mortality in either group. One year after the procedure, the LVOT gradients for the 2 groups were not statistically different. During the follow-up, moderate MR was found in 4 patients (25%) in the ablation group and in 2 patients (8.3%) in the myectomy group. Exercise capacity and New York Heart Association class improved after PSMA, whereas postoperative MR severity and effort capacity were better in the surgical group.

CONCLUSION

The 2 approaches yielded similar results with regard to reducing the LVOT gradient. We conclude that SM is preferable to PSMA in cases with MR.

Comparison of Surgical Septal Myectomy and Alcohol Septal Ablation With Cardiac Magnetic Resonance Imaging in Patients With Hypertrophic Obstructive Cardiomyopathy

OBJECTIVES

This study sought to describe the acute morphologic differences that result from septal myectomy and alcohol septal ablation using cardiac magnetic resonance (CMR) imaging.

BACKGROUND

Surgical septal myectomy and alcohol septal ablation relieve left ventricular outflow tract obstruction in severely symptomatic patients with hypertrophic cardiomyopathy (HCM).

METHODS

Cine and contrast-enhanced CMR images were obtained in HCM patients before and after septal myectomy (n = 24) and alcohol septal ablation (n = 24). Location of septal reduction, extent of myocardial necrosis, and conduction system abnormalities with each technique were compared.

RESULTS

With septal myectomy, there was a discrete area of resected tissue consistently localized to anterior septum. In contrast, alcohol septal ablation resulted in a more variable effect. In most patients, alcohol septal ablation caused a transmural region of tissue necrosis, located more inferiorly in the basal septum than myectomy and usually extending into the right ventricular side of the septum at the midventricular level. However, there were 6 patients after alcohol septal ablation in whom there was sparing of the basal septum with residual gradients at follow-up. After the procedure, left bundle branch block developed in 46% of septal myectomy patients, and right bundle branch block was evident in 58% of alcohol septal ablation patients.

CONCLUSIONS

Septal myectomy and alcohol septal ablation for severely symptomatic, drug-refractory patients with obstructive HCM have different morphologic effects and location sites on left ventricular septal myocardium. Septal myectomy provides consistent resection of the obstructing portion of the anterior basal septum, whereas the effect of ethanol septal ablation is more variable. These findings may have important implications for patient selection and management as well as long-term outcome.

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.

Pathological effects of alcohol septal ablation for hypertrophic obstructive cardiomyopathy

BACKGROUND

The pathological effects and the mechanisms of action of intracoronary administration of ethanol for alcohol septal ablation (ASA) for the management of hypertrophic obstructive cardiomyopathy (HOCM) are unknown.

METHODS

We examined surgical specimens and, in one case, autopsy specimens from four patients who underwent surgical septal myectomy 2 days to 14 months after unsuccessful ASA.

RESULTS

Pathological examination early after ASA showed coagulative necrosis of both the myocardium and the septal perforator arteries. Affected arteries were distended and occluded by necrotic intraluminal debris, without platelet-fibrin thrombi. Late after unsuccessful ASA, excised septal tissue was heterogeneous, containing a region of dense scar, and adjacent tissue containing viable myocytes and interspersed scar.

CONCLUSIONS

Intracoronary administration of ethanol in patients with HOCM causes acute myocardial infarction with vascular necrosis. The coagulative necrosis of the arteries, their distension by necrotic debris and the absence of platelet-fibrin thrombi distinguish ethanol-induced infarction from that caused by atherosclerotic coronary artery disease. The direct vascular toxicity of ethanol may be an important aspect of the mechanism of successful ASA.

Percutaneous Versus Surgical Treatment for Patients With Hypertrophic Obstructive Cardiomyopathy and Enlarged Anterior Mitral Valve Leaflets

Background— The purpose of this study was to compare percutaneous transluminal septal myocardial ablation (PTSMA) and septal myectomy combined with mitral leaflet extension (MLE) in symptomatic hypertrophic obstructive cardiomyopathy patients with an enlarged anterior mitral valve leaflet (AMVL). Both PTSMA and myectomy reduce septal thickness and left ventricular outflow tract (LVOT) gradient; however, an uncorrected enlarged AMVL may predispose to residual systolic anterior motion (SAM) after successful standard myectomy or PTSMA. Myectomy with MLE previously demonstrated superior hemodynamic results compared with standard myectomy, but its value relative to PTSMA is unknown.

Methods and Results— Twenty-nine patients (aged 44±12 years) underwent myectomy with MLE, and 43 patients (aged 52±17 years) underwent PTSMA. Mitral leaflet area was similar in both groups (16.7±3.4 versus 15.9±2.7 cm 2 , respectively). After PTSMA, 2 patients died, 4 needed a reintervention, and 4 required a permanent pacemaker for complete heart block. After surgery, only 1 patient needed a reintervention. At 1-year follow-up, LVOT gradients did not differ between surgical and PTSMA patients (17±14 versus 23±19 mm Hg, respectively). Preinterventional mitral regurgitation grade was more severe in the surgical group, but with myectomy combined with MLE, the residual grade was similar to that of PTSMA. Mean SAM grade decreased significantly more after surgery (from 2.9±0.3 to 0.5±0.7 mm Hg versus from 2.8±0.5 to 1.3±0.9 mm Hg, P <0.05).

Conclusions— PTSMA in these selected patients with hypertrophic obstructive cardiomyopathy had more periprocedural complications and resulted in more reinterventions. Hemodynamic results (SAM grade and reduction in mitral regurgitation) were better in surgical patients.

Clinical and Echocardiographic Determinants of Long-Term Survival After Surgical Myectomy in Obstructive Hypertrophic Cardiomyopathy

Background— Surgical myectomy has been the standard treatment for patients with drug-refractory obstructive hypertrophic cardiomyopathy. The clinical and echocardiographic predictors of long-term survival and freedom from cardiovascular morbidity after myectomy have been unclear.

Methods and Results— We studied a consecutive cohort of 338 adult patients (age at operation 47±14 [range 18 to 77] years, 60% male) who underwent myectomy at our institution. Preoperative resting left ventricular outflow tract (LVOT) gradient was 66±32 mm Hg (range 5 to 158 mm Hg). Early postoperative mortality was 1.5% (5 deaths): 4 deaths occurred between 1978 and 1992, and 1 death occurred between 1993 and 2002. During long-term follow-up, 83% of patients reported an improvement to functional class I or II. The majority of patients (98%) had no resting LVOT gradient. Long-term survival was excellent, with 98±1% survival at 1 year, 95±1% at 5 years, and 83±3% at 10 years after myectomy. Multivariable Cox regression analysis identified 5 predictors of overall mortality: (1) age ≥50 years at surgery (hazard ratio [HR] 2.8, 95% CI 1.5 to 5.1, P =0.001), (2) female gender (HR 2.5, 95% CI 1.5 to 4.3, P =0.0009), (3) history of preoperative atrial fibrillation (HR 2.2, 95% CI 1.2 to 4.0, P =0.008), (4) concomitant CABG (HR 3.7, 95% CI 1.7 to 8.2, P =0.001), and (5) preoperative left atrial diameter ≥46 mm (HR 2.9, 95% CI 1.6 to 5.4, P =0.0008). Significant predictors of late major cardiovascular events found on multivariable analysis were (1) female gender (HR 3.3, 95% CI 2.0 to 5.4, P <0.0001), (2) history of preoperative atrial fibrillation (HR 1.9, 95% CI 1.1 to 3.3, P =0.02), and (3) preoperative left atrial diameter ≥46 mm (HR 2.5, 95% CI 1.5 to 4.3, P =0.0008).

Conclusions— Myectomy provides excellent relief for LVOT obstruction in patients with hypertrophic cardiomyopathy. Preoperative clinical and echocardiographic variables can predict long-term outcome after myectomy.

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.

Impact of Right Atrial-Left Ventricular Dual-Chamber Permanent Pacing in Patients With Severely Symptomatic Hypertrophic Obstructive Cardiomyopathy

BACKGROUND

Effective alternatives to surgical myectomy for patients with symptomatic hypertrophic obstructive cardiomyopathy (HOCM) remain unestablished. Dual-chamber (DDD) pacing was evaluated in these patients using right atrial (RA) and epicardial left ventricular (LV) leads.

METHODS AND RESULTS

In 6 patients with HOCM refractory to medical therapy and conventional RA-right ventricular (RV) DDD pacing, we implanted DDD pacemakers using RA and epicardial LV leads. The baseline intraventricular pressure gradient before pacemaker implantation was 103+/-44 mmHg. The pressure gradient decreased significantly to 8+/-16 mmHg by temporary RA-LV DDD pacing (p=0.006), while it decreased only to 68+/-25 mmHg by temporary RA-RV pacing (NS). It was nearly eliminated to 1+/-2 mmHg (p=0.027) 3 months after RA-LV DDD pacemaker implantation. LV end-diastolic pressure, cardiac index and systolic aortic pressure did not change significantly. New York Heart Association class improved in all patients (p=0.023). Brain and atrial natriuretic peptide concentrations, respectively 516+/-286 and 143+/-34 pg/ml at baseline, decreased significantly to 230+/-151 and 93+/-44 pg/ml 3 months after implantation (p=0.027 and 0.028).

CONCLUSION

RA-LV DDD pacemaker implantation is a useful option for patients with symptomatic HOCM.

Alcohol septal ablation for hypertrophic cardiomyopathy: Indications and technique

Alcohol septal ablation for the treatment of hypertrophic cardiomyopathy has been the subject of great interest, and the number of procedures performed is increasing despite an absence of randomized trial data. Although straightforward in concept, alcohol septal ablation may be considerably more difficult in actual practice. To optimize the results and prevent complications, the anatomy of the septal arcade architecture must be understood and the anatomic relationship between the septal artery and the specific portion of the septum to be ablated must be carefully delineated. For the latter, during the procedure, an echocardiographic contrast medium injection into the septal artery of interest is essential. Selection of the volume and amount of alcohol to be injected varies depending on the size and distribution of the septal artery. Specific complications such as conduction defects, hemodynamic compromise, ventricular arrhythmias, and inadequate gradient reduction can be minimized by specific technical approaches. After ablation, protocols are needed for periprocedural guidelines because some complications may occur late during the next several days. For optimal results, patients need to be selected after catheter assessment and combined echocardiography and angiography, and ablation techniques need to be scientific and rigorous.

Usefulness of real-time three-dimensional echocardiography for evaluation of myectomy in patients with hypertrophic cardiomyopathy

Real-time 3-dimensional echocardiography was performed in 10 patients with obstructive hypertrophic cardiomyopathy (HC) before and after myectomy and in 6 controls. The exact location of systolic anterior motion of the mitral leaflet was shown in all patients with HC with a predominant involvement of the medial portion in 4 patients and the middle portion in 6 patients. The smallest area of the left ventricular outflow tract was significantly smaller in patients with HC than in controls (1.4 +/- 0.7 vs 5.1 +/- 1.2 cm(2), p <0.01), significantly increased after myectomy (4.8 +/- 1.8 cm2, p <0.01) and was associated with a reduction of the pressure gradient at rest from 63 +/- 41 to 15 +/- 5 mm Hg (p <0.01).

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).

Monomorphic ventricular tachycardia: a late complication of percutaneous alcohol septal ablation for hypertrophic cardiomyopathy

Percutaneous alcohol septal ablation has emerged as a promising treatment option for patients with symptomatic hypertrophic obstructive cardiomyopathy. Although the procedure involves an alcohol-induced myocardial infarction and results in a substrate potentially conducive to re-entrant tachyarrhythmias, late-occurring ventricular arrhythmias have not been described. We report a case of monomorphic ventricular tachycardia occurring several days after alcohol septal ablation. Patients with hypertrophic cardiomyopathy undergoing alcohol septal ablation should be considered for prophylactic placement of implantable cardioverter defibrillator.

Management of hypertrophic cardiomyopathy in children

Hypertrophic cardiomyopathy (HCM) is an inherited cardiac disease characterized by unexplained left ventricular hypertrophy, typically involving the interventricular septum. Hypertrophy may be present in infants, but commonly develops during childhood and adolescence. Management of children with HCM aims to provide symptomatic relief and prevention of sudden death, which is the primary cause of death. Unfortunately, no randomized comparative trials to date have assessed different treatment options in HCM. Medical treatment with negative inotropic agents (beta-adrenoceptor antagonists [beta-blockers], verapamil) is the first therapeutic choice in all symptomatic patients. Beta-blockers also appear to have prognostic merit in children. Surgical myectomy is effective in reducing symptoms in children with left ventricular (LV) obstruction who are unresponsive to medical treatment, although a repeat operation may be needed in a substantial proportion of patients due to relapse of LV obstruction. The recently introduced percutaneous septal ablation can also be regarded as a feasible alternative in this cohort. Technical limitations of both invasive therapeutic options should be carefully considered, preferably in experienced centers. Results of recent randomized trials indicate that dual chamber pacing, once considered a therapeutic option for patients with HCM, should only be used as treatment for conduction abnormalities. Regular clinical risk stratification for sudden death is of vital importance for the prevention of sudden death in young patients. Familial history of sudden death at a young age, LV hypertrophy >3 cm, unexplained syncope, nonsustained ventricular tachycardia in Holter monitoring, and abnormal blood pressure response during exercise are currently considered clinical risk factors for sudden death. Each factor has a low positive predictive accuracy, but patients having two or more of these risk factors are deemed as high risk. Secondary prevention of sudden death in patients successfully resuscitated from cardiac arrest and/or sustained ventricular tachycardia warrants treatment with an implantable cardioverter defibrillator (ICD). Primary prevention of sudden death in patients considered to be at high risk should aim at the management of obvious arrhythmogenic mechanisms (paroxysmal atrial fibrillation, sustained monomorphic ventricular tachycardia, conduction system disease, accessory pathway, myocardial ischemia), and the prevention and/or management of ventricular tachyarrhythmias with amiodarone and/or ICD implantation, respectively. The choice of treatment in children is greatly influenced by technical aspects, such as adverse effects of amiodarone, and ICD implantation difficulties or complications. Amiodarone could also be used as a bridge in children at high risk, until they reach adulthood, possibly achieving a lower risk status, or until their physical growth permits ICD implantation as long-term therapy.

Cardiac transplantation for hypertrophic cardiomyopathy: a valid therapeutic option

BACKGROUND

Hypertrophic cardiomyopathy is a rare indication for cardiac transplantation, with only anecdotal reports in the literature. Transplantation has been proposed to patients with hypertrophic cardiomyopathy who remained symptomatic despite optimal medical treatment or who progressed to congestive heart failure, and when conventional surgical correction was not or was no longer possible. In this report, we analyze the clinical results of cardiac transplantation in these patients.

METHODS

We retrospectively reviewed complete clinical data and prospectively gathered complete follow-up data for 14 patients who underwent orthotopic cardiac transplantation for hypertrophic cardiomyopathy at the Montreal Heart Institute and Ste-Justine Hospital between 1984 and 2001.

RESULTS

Ten male (71.4%, 5 adults and 5 children) and 4 female (28.6%, 2 adults and 2 children) patients underwent heart transplantation for hypertrophic cardiomyopathy. The median age of the recipients in the pediatric group was 13 years (range, 6-16) and was 40 years (range, 22-46) in the adult group. Median duration of follow-up was 9.5 years (mean, 8.8 +/- 4.8 years; range, 1-18) and was 100% complete. We found no operative mortality and found 2 late deaths related to coronary graft atherosclerosis. Long-term survival at 5, 10, and 15 years was 100%, 85%, and 64%, respectively. Freedom from acute rejection at 1, 5, and 10 years was 73%, 32%, and 9%, respectively. The remaining 11 survivors exhibit few symptoms and are currently in New York Heart Association Class I or II.

CONCLUSIONS

Cardiac transplantation is a valid therapeutic option for patients with symptomatic hypertrophic cardiomyopathy who do not respond to optimal medical management and who are not candidates for conventional surgical treatment. The long-term outcome is excellent in these patients.

Conduction system abnormalities in patients with obstructive hypertrophic cardiomyopathy following septal reduction interventions

We observed the impact of percutaneous transluminal septal myocardial ablation (PTSMA) and myectomy on the conduction system in patients with obstructive hypertrophic cardiomyopathy (HC). Septal reduction intervention is capable of eliminating the left ventricular outflow tract obstruction in patients with obstructive HC; however, conduction system abnormalities are frequent consequences of these procedures. A standard 12-lead electrocardiogram and Doppler echocardiogram were obtained in 204 patients who underwent PTSMA (n = 70) or myectomy (n = 134) before and at average of 3 months after intervention. Of 146 patients who had normal conduction systems before intervention, the duration of the QRS complex was significantly prolonged from 98 +/- 15 to 130 +/- 25 ms (p <0.0001), with right bundle branch block (RBBB) developing in 62% patients after PTSMA, and from 100 +/- 13 to 154 +/- 20 ms (p <0.0001), with left bundle branch block (LBBB) developing in 93% patients after myectomy. No significant difference in the QRS duration was found in the remaining 58 patients who had preexisting conduction abnormalities after intervention. In 174 patients without a preexisting permanent pacemaker, a pacemaker was implanted in 22% versus 13% of patients who underwent PTSMA (overall and without preexisting conduction block, respectively) and 10% versus 2% of patients with myectomy. The duration of baseline QRS was an independent predictor for the requirement of a permanent pacemaker (p <0.0001). Thus, RBBB often develops after PTSMA and LBBB is very frequently produced by myectomy. A possible requirement of a permanent pacemaker should always be considered before intervention when patients have preexisting RBBB or LBBB.

Catheter-Based Approach to Mitral Regurgitation

Mitral Regurgitation (MR) is a common medical problem. MR is also a prognostic factor; patients with severe symptomatic MR have a poor prognosis with an annual mortality rate of 5% without surgical intervention. An anatomic understanding of the normal and regurgitant mitral valve is essential in order to evaluate appropriately the severity and impact of MR. We briefly discuss mitral complex anatomy, MR evaluation, and treatment options (surgical and catheter-based alternatives) according to the type of lesion found. In particular, our group has shown temporal percutaneous annuloplasty and definitive percutaneous edge-to-edge mitral valve repair to be a feasible technique. Recently a study evaluating endovascular mitral valve edge-to-edge repair was successfully initiated by our group. Acute and chronic ischemic mitral regurgitation and special situations, such as paravalvular leaks, hypertrophic obstructive cardiomyopathy, and mixed lesions are also discussed. Future directions may include the percutaneous transcatheter implantation of a bioprosthetic valve in mitral position.

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.

Sudden death of a case of hypertrophic obstructive cardiomyopathy 19 months after successful percutaneous transluminal septal myocardial ablation

A 56-year-old male with hypertrophic obstructive cardiomyopathy complicated with medically refractory paroxysmal atrial fibrillation and congestive heart failure was treated with percutaneous transluminal septal myocardial ablation. The resting left ventricular outflow tract gradient decreased from 70 mmHg to 0 mmHg after the procedure, and clinical symptoms improved dramatically. However, the patient died suddenly 19 months later and autopsy revealed nontransmural myocardial fibrosis with an irregular border in the interventricular septum.

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.

Hypertrophic Cardiomyopathy

When an individual is diagnosed with hypertrophic cardiomyopathy (HCM), all relatives potentially affected by Mendelian autosomal-dominant inheritance should be evaluated with an electrocardiogram (ECG) and echocardiogram. Genetic testing should be considered in high-risk mutations where there are diagnostic uncertainties. Symptom relief depends on beta-blockers as first-line therapy. If the disease is nonobstructive, then calcium channel blockers can be added or used alone. If there is a significant left ventricular outflow tract (LVOT) gradient then disopyramide can be used, ideally in combination with a beta-blocker. Verapamil should be used with care due to potential exacerbation of the LVOT gradient. Nonmedical therapy for obstructive disease consists of surgical myectomy, alcohol septal ablation, or dual-chamber pacing. Surgery is the gold standard, although in experienced hands and directed appropriately, septal ablation achieves good results. Pacing is generally less effective. The development of atrial fibrillation (AF) or left atrial enlargement carries a significant risk of thromboembolism. All patients should be closely observed for AF and thromboembolic risk, and the threshold for initiation of anticoagulation should be low in patients with sustained palpitations, atrial enlargement, and nonsustained supraventricular arrhythmia on Holter. All patients with HCM should be assessed for their risk of sudden death regardless of severity of symptoms or morphology. The factors predictive of risk are 1) previous cardiac arrest; 2) unexplained syncope; 3) family history of premature sudden death; 4) abnormal blood pressure response to exercise; 5) nonsustained ventricular tachycardia; and 6) severe left ventricular hypertrophy >/= 30 mm.

Outcome of patients with hypertrophic obstructive cardiomyopathy after percutaneous transluminal septal myocardial ablation and septal myectomy surgery

OBJECTIVES

This study was conducted to evaluate follow-up results in patients with hypertrophic obstructive cardiomyopathy (HOCM) who underwent either percutaneous transluminal septal myocardial ablation (PTSMA) or septal myectomy.

BACKGROUND

Controversy exists with regard to these two forms of treatment for patients with HOCM.

METHODS

Of 51 patients with HOCM treated, 25 were treated by PTSMA and 26 patients via myectomy. Two-dimensional echocardiograms were performed before both procedures, immediately afterwards and at a three-month follow-up. The New York Heart Association (NYHA) functional class was obtained before the procedures and at follow-up.

RESULTS

Interventricular septal thickness was significantly reduced at follow-up in both groups (2.3 +/- 0.4 cm vs. 1.9 +/- 0.4 cm for septal ablation and 2.4 +/- 0.6 cm vs. 1.7 +/- 0.2 cm for myectomy, both p < 0.001). Estimated by continuous-wave Doppler, the resting pressure gradient (PG) across the left ventricular outflow tract (LVOT) significantly decreased immediately after the procedures in both groups (64 +/- 39 mm Hg vs. 28 +/- 29 mm Hg for PTSMA, 62 +/- 43 mm Hg vs. 7 +/- 7 mm Hg for myectomy, both p < 0.0001). At three-month follow-up, the resting PG remained lower in the PTSMA and myectomy groups (24 +/- 19 mm Hg and 11 +/- 6 mm Hg, respectively, vs. those before procedures, both p < 0.0001). The NYHA functional class was also significantly improved in both groups (3.5 +/- 0.5 vs. 1.9 +/- 0.7 for PTSMA, 3.3 +/- 0.5 vs. 1.5 +/- 0.7 for myectomy, both p < 0.0001).

CONCLUSIONS

Both myectomy and PTSMA reduce LVOT obstruction and significantly improve NYHA functional class in patients with HOCM. However, there are benefits and drawbacks for each therapeutic method that must be counterbalanced when deciding on treatment for LVOT obstruction.

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.

Cardiac pacing. A review

Pacing is a field of rapid clinical progress and technologic advances. Clinical progress in the 1990s included the refinement of indications for pacing as well as the use of pacemakers for new, nonbradycardiac indications, such as the treatment of cardiomyopathies and CHF and the prevention of atrial fibrillation. Important published data and studies in progress are shedding new light on issues of pacing mode selection, and they may influence future practice significantly. Important technologic advances include development of new rate-adaptive sensors and sensor combinations and the evolution of pacemakers into sophisticated diagnostic devices with the capability to store data and ECGs. Automatic algorithms monitor the patient for appropriate capture, sensing, battery status, and lead impedance, providing better patient safety and pacemaker longevity.

Utility of cardiopulmonary exercise in the assessment of clinical determinants of functional capacity in hypertrophic cardiomyopathy

The utility of metabolic gas exchange measurements in evaluating the severity and determinants of exercise limitation was studied during upright symptom-limited cardiopulmonary exercise in 135 consecutive patients with hypertrophic cardiomyopathy (HC) and 50 healthy age- and gender-matched volunteers. Peak oxygen consumption (VO(2)) was less than predicted (age, gender, and size) in 99% patients. Peak VO(2) was significantly associated with New York Heart Association functional class; however, there was considerable overlap of peak VO(2) between classes I and III (70 +/- 15%, 56 +/- 15%, 35 +/- 11%, respectively). Patients with abnormal blood pressure responses and patients with chronotropic incompetence during exercise had lower percent-predicted peak VO(2) than patients with normal blood pressure and heart rate responses during exercise (p = 0.0001 and p <0.001, respectively). Percent-predicted peak VO(2) was similar in patients with and without resting left ventricular outflow obstruction. Of those patients with resting gradients, however, there was a strong inverse correlation between the magnitude of the gradient and peak VO(2) (r = 0.5; p <0.001). In conclusion, peak VO(2) is significantly related to New York Heart Association functional class in this group of patients with HC, but peak VO(2) is a superior measure of cardiovascular performance in individual patients. Our peak VO(2) data indicate that mechanical obstruction has an adverse pathophysiologic effect on functional capacity and provide the rationale to support treatments aimed at gradient reduction. Low peak VO(2) characteristics including those with normal or near-normal left ventricular wall thickness suggests that measurement of peak VO(2) may aid in the differential diagnosis between HC and athlete's heart.

The value of magnetic resonance imaging of the left ventricular outflow tract in patients with hypertrophic obstructive cardiomyopathy after septal artery embolization

BACKGROUND

We tested the value of magnetic resonance imaging (MRI) in the follow-up of patients with hypertrophic obstructive cardiomyopathy after septal artery embolization. MRI provides a noninvasive visualization of transplanar turbulent flow in order to quantify left ventricular outflow tract obstruction.

METHODS AND RESULTS

We followed 10 patients who were treated with septal artery embolization for 12 months. We used gradient echo sequences to document continuous improvement of the outflow tract area and T1- and T2-weighted spin echo sequences to visualize myocardial infarction. A continuous, but not linear, improvement of the outflow tract area occurred after septal artery embolization during the 12-month follow-up period. The improvement of the outflow tract area correlated well with the amelioration of symptoms (r(2)=0.86).

CONCLUSIONS

We conclude that MRI reliably detects the degree of obstruction in patients with hypertrophic obstructive cardiomyopathy. This modality may be especially useful for follow-up after septal artery embolization.

Medical therapy versus interventional therapy in hypertropic obstructive cardiomyopathy

Medical treatment in symptomatic patients with hypertrophic obstructive cardiomyopathy aims to reduce the outflow tract gradients, and to improve diastolic dysfunction and rhythm disorders. Surgical myectomy is the standard treatment in patients with drug refractory symptoms. Since the early 1990s, dual-chamber (DDD)-pacemaker implantation and percutaneous transluminal septal myocardial ablation by alcohol-induced septal branch occlusion have widened treatment options in this subgroup of patients. An overview of medical and interventional treatment is presented.