Catheter-based therapy for hypertrophic obstructive cardiomyopathy

Predicting complete heart block after alcohol septal ablation for hypertrophic cardiomyopathy using a risk stratification model and clinical tool

BACKGROUND

Alcohol septal ablation (ASA) is a proven method of septal reduction for patients with drug refractory, symptomatic hypertrophic obstructive cardiomyopathy (HOCM). This procedure is associated with a 6.5-11% risk of complete heart block (CHB).

OBJECTIVE

The aim of this study is to determine factors that predict CHB and to develop a clinical tool for risk stratification of patients.

METHODS

Patients were enrolled into an ongoing ASA study. A total of 636 patient procedures were included, 527 of whom were used in the development of the prediction tool, and 109 of whom were used for independent validation. Multivariate analysis was performed with odds ratios used to develop the clinical prediction tool. This was then internally and externally validated.

RESULTS

Of the 527 in the prediction cohort, 46 developed CHB. The predictors of CHB were age ≥50 years, pre-ASA left bundle branch block (LBBB), transient procedural high-grade block, post-ASA PR prolongation ≥68 ms, and new bifascicular block. An 11-point clinical prediction tool was developed to classify these factors. Internal validation using a receiver operating characteristic curve revealed an area under the curve of 0.88 for the clinical prediction tool. External validation using 109 contemporary patients revealed a 98% negative predictive value, 24% positive predictive value, 75% sensitivity, and 81% specificity in high-risk patients.

CONCLUSION

Among patients undergoing ASA, the risk of CHB can be predicted with easily obtained clinical and electrocardiographic factors. This clinical prediction tool allows identification of high-risk patients who may benefit from additional monitoring and therapy.

Alcohol dose in septal ablation for hypertrophic obstructive cardiomyopathy

BACKGROUND

The aim of this study was to evaluate short- and long-term outcomes related to dose of alcohol administered during alcohol septal ablation (ASA) in patients with hypertrophic obstructive cardiomyopathy (HOCM). Current guidelines recommend using 1-3 mL of alcohol administered in the target septal perforator artery, but this recommendation is based more on practical experience of interventionalists rather than on systematic evidence.

METHODS

We included 1448 patients and used propensity score to match patients who received a low-dose (1.0-1.9 mL) versus a high-dose (2.0-3.8 mL) of alcohol during ASA.

RESULTS

The matched cohort analysis comprised 770 patients (n = 385 in both groups). There was a similar occurrence of 30-day post-procedural adverse events (13% vs. 12%; p = 0.59), and similar all-cause mortality rates (0.8% vs. 0.5%; p = 1) in the low-dose group and the high-dose group, respectively. In the long-term follow-up (5.4 ± 4.5 years), a total of 110 (14%) patients died representing 2.58 deaths and 2.64 deaths per 100 patient-years in the low dose and the high dose group (logrank, p = 0.92), respectively. There were no significant differences in the long-term dyspnea and left ventricular outflow gradient between the two groups. Patients treated with a low-dose of alcohol underwent more subsequent septal reduction procedures (logrank, p = 0.04).

CONCLUSIONS

Matched HOCM patients undergoing ASA with a low-dose (1.0-1.9 mL) or a high-dose (2.0-3.8 mL) of alcohol had similar short- and long-term outcomes. A higher rate of repeated septal reduction procedures was observed in the group treated with a low-dose of alcohol.

Hypertrophic obstructive cardiomyopathy: what, when, why, for whom?

Hypertrophic cardiomyopathy is the most common genetic cardiovascular disorder and is associated with symptoms of heart failure and increased risk of sudden cardiac death. The most common condition is obstruction of the left ventricular outflow tract. Surgical septal myectomy and alcohol septal ablation are the 2 accepted modes of septal reduction therapy and are indicated when there are advanced symptoms and a peak left ventricular outflow gradient ≥50 mmHg. Advantages of alcohol septal ablation are limited groin approach, reduction of obstruction of the left ventricular outflow tract and functional improvement, but there are higher chances for intracardiac device implantation and residual obstruction. Septal myectomy offers very low mortality, absolute and immediate resolution of obstruction of the left ventricular outflow tract and survival comparative to a matched general population with almost negligible residual obstruction. It is recommended that patients with obstructive hypertrophic cardiomyopathy should be treated at experienced centres.

Hypertrophic Cardiomyopathy-Past, Present and Future

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

Long-term clinical outcome after alcohol septal ablation for obstructive hypertrophic cardiomyopathy: results from the Euro-ASA registry

AIMS

The first cases of alcohol septal ablation (ASA) for obstructive hypertrophic cardiomyopathy (HCM) were published two decades ago. Although the outcomes of single-centre and national ASA registries have been published, the long-term survival and clinical outcome of the procedure are still debated.

METHODS AND RESULTS

We report long-term outcomes from the as yet largest multinational ASA registry (the Euro-ASA registry). A total of 1275 (58 ± 14 years, median follow-up 5.7 years) highly symptomatic patients treated with ASA were included. The 30-day post-ASA mortality was 1%. Overall, 171 (13%) patients died during follow-up, corresponding to a post-ASA all-cause mortality rate of 2.42 deaths per 100 patient-years. Survival rates at 1, 5, and 10 years after ASA were 98% (95% CI 96-98%), 89% (95% CI 87-91%), and 77% (95% CI 73-80%), respectively. In multivariable analysis, independent predictors of all-cause mortality were age at ASA (P < 0.01), septum thickness before ASA (P < 0.01), NYHA class before ASA (P = 0.047), and the left ventricular (LV) outflow tract gradient at the last clinical check-up (P = 0.048). Alcohol septal ablation reduced the LV outflow tract gradient from 67 ± 36 to 16 ± 21 mmHg (P < 0.01) and NYHA class from 2.9 ± 0.5 to 1.6 ± 0.7 (P < 0.01). At the last check-up, 89% of patients reported dyspnoea of NYHA class ≤2, which was independently associated with LV outflow tract gradient (P < 0.01).

CONCLUSIONS

The Euro-ASA registry demonstrated low peri-procedural and long-term mortality after ASA. This intervention provided durable relief of symptoms and a reduction of LV outflow tract obstruction in selected and highly symptomatic patients with obstructive HCM. As the post-procedural obstruction seems to be associated with both worse functional status and prognosis, optimal therapy should be focused on the elimination of LV outflow tract gradient.

Percutaneous Septal Ablation in Hypertrophic Obstructive Cardiomyopathy: From Experiment to Standard of Care

Hypertrophic cardiomyopathy (HCM) is one of the more common hereditary cardiac conditions. According to presence or absence of outflow obstruction at rest or with provocation, a more common (about 60-70%) obstructive type of the disease (HOCM) has to be distinguished from the less common (30-40%) nonobstructive phenotype (HNCM). Symptoms include exercise limitation due to dyspnea, angina pectoris, palpitations, or dizziness; occasionally syncope or sudden cardiac death occurs. Correct diagnosis and risk stratification with respect to prophylactic ICD implantation are essential in HCM patient management. Drug therapy in symptomatic patients can be characterized as treatment of heart failure with preserved ejection fraction (HFpEF) in HNCM, while symptoms and the obstructive gradient in HOCM can be addressed with beta-blockers, disopyramide, or verapamil. After a short overview on etiology, natural history, and diagnostics in hypertrophic cardiomyopathy, this paper reviews the current treatment options for HOCM with a special focus on percutaneous septal ablation. Literature data and the own series of about 600 cases are discussed, suggesting a largely comparable outcome with respect to procedural mortality, clinical efficacy, and long-term outcome.

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.

Alcohol septal ablation for hypertrophic obstructive cardiomyopathy

Since its original description in 1994, alcohol septal ablation (ASA) has emerged as a minimally invasive modality for treatment of hypertrophic obstructive cardiomyopathy compared to surgical myomectomy. This catheter-based intervention relies on the injection of absolute alcohol into the septal perforator to induce a controlled infarction of the hypertrophied septum and consequently abolish the dynamic outflow obstruction. This gradient reduction has been correlated with a significant clinical improvement in the patient’s symptomatology and with left ventricular remodeling. The procedure has been refined throughout the years, especially with the introduction of myocardial contrast echocardiography for localization of the area at risk of infarction and the reduction in the amount of alcohol used. Major complications of ASA are uncommon in large referral centers but conduction system disturbances has been the most commonly reported complications of ASA with 10% of patients necessitating permanent pacemaker implantation for complete heart block. ASA has not been compared to the gold standard surgical myomectomy in a randomized prospective study. We review the clinical aspects of this procedure and provide some historical background.

Follow-up by cardiac magnetic resonance imaging in patients with hypertrophic cardiomyopathy who underwent percutaneous ventricular septal ablation

To evaluate myocardial infarction and describe the early to mid-term changes induced by percutaneous ventricular septal ablation (PVSA) in symptomatic patients with hypertrophic cardiomyopathy using cardiac magnetic resonance imaging. Cardiac magnetic resonance imaging was performed before and 1 week and 1 year after PVSA in 52 patients. The relation between the infarction size and other factors was determined. At 1 week after PVSA, regional hyperenhancement was visualized in the basal interventricular septum in all patients. The mean infarction size was 29.5 ± 15.9 g. The infarction size correlated well with the ethanol volume. The left ventricular myocardial mass decreased significantly from 196.1 ± 65.9 g at baseline to 183.4 ± 63.6 g 1 week after PVSA (p <0.001) and 164.1 ± 60.9 g within the 1-year follow-up period (p <0.001). In conclusion, cardiac magnetic resonance imaging allowed a detailed evaluation of the size and location of septal myocardial infarction induced by PVSA. The left ventricular myocardial mass decreased significantly during the follow-up period.

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.

Dispelling the myths about omega-3 fatty acids

Although there is an enormous amount of information available on omega-3 fatty acids, it is sometimes misleading, contradictory, and unsupported by scientific fact. Consumers and medical professionals may be confused regarding the potential value of omega-3 fatty acid supplements, despite having either read or heard about fi sh oil consumption and/or omega-3 fatty acid benefits and risks. The availability of a prescription formulation of omega-3-acid ethyl esters (P-OM3) has provided important new information that helps to dispel the myths and alleviate concerns surrounding the use of omega-3 fatty acids in clinical practice. The safety and efficacy of P-OM3, but not dietary-supplement omega-3 fatty acids, are documented in placebo-controlled trials. In general, studies using Food and Drug Administration-approved dosages of P-OM3 have not substantiated various myths surrounding the negative effects of omega-3 fatty acids. Thus, there are now evidence-based clinical guidelines for the use of omega-3 fatty acids in clinical practice.

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.

One-year follow-up of percutaneous septal ablation for symptomatic hypertrophic obstructive cardiomyopathy in 312 patients: predictors of hemodynamic and clinical response

AIM

The aim of this study was to analyze hemodynamic and clinical outcome in a cohort of 312 patients who were followed up over a period of 12 months after alcohol septal ablation (PTSMA) for symptomatic hypertrophic obstructive cardiomyopathy (HOCM).

METHODS AND RESULTS

PTSMA was intended in 337 patients with HOCM (mean age: 54+/-15 years), with 312 procedures completed by injection of 2.8+/-1.2 ml of alcohol. In 25 patients (8%) the intervention was aborted, mostly because of contrast echocardiographic findings. In the 312 patients who received alcohol, permanent pacing was necessary in 22 cases (7%); and in-hospital mortality was 1.3% (four patients). During follow-up, contact to six patients (2%) was lost, and three additional patients (1%) died. The 299 patients who either underwent non-invasive reassessment in our institution or transmitted followup data from their local physician formed the study population. Improvement in symptoms was reported by 272 patients (91%). Mean NYHA functional class was reduced from 2.9+/-0.4 to 1.5+/-0.7 (p<0.0001) along with a gradient reduction (echo-Doppler) from 59+/-32 to 8+/-15 mmHg at rest, and from 120+/-42 to 28+/-32 mmHg with provocation (p<0.0001 each). Exercise capacity improved from 94+/-51 to 119+/-40 watts (p=0.001), and peak oxygen consumption from 18+/-4 to 21+/-6 ml/ kg/min (p=0.01). Younger age and higher outflow gradients at baseline and immediately after intervention were associated with a less favorable hemodynamic outcome. The degree of limitation of exercise capacity at baseline was the only predictor of symptomatic improvement.

CONCLUSIONS

Catheter-based septal ablation is an effective non-surgical technique for reducing symptoms and outflow gradients in HOCM. In contrast to a previous study, in this cohort of 312 patients there was no association between post-interventional enzyme release and hemodynamic success. Younger patients with high baseline gradients, however, tended to have a less favorable hemodynamic outcome with higher residual gradients.

Predictors of Complete Heart Block After Transcoronary Ablation of Septal Hypertrophy

OBJECTIVES

This study analyzed changes in intracardiac conduction during transcoronary ablation of septal hypertrophy (TASH) to identify predictors for pacemaker dependency after TASH.

BACKGROUND

Transcoronary ablation of septal hypertrophy is an accepted therapeutic option in hypertrophic obstructive cardiomyopathy (HOCM). However, atrioventricular conduction disorders, requiring permanent pacemaker implantation, remain a major adverse effect.

METHODS

This study measured changes in intracardiac conduction in 172 consecutive patients during TASH by simultaneously recording electrophysiological parameters and correlated these parameters with the occurrence of complete heart block during continuous electrocardiographic monitoring for 8 days.

RESULTS

Intraprocedural complete heart block occurred in 36 patients (20.1%) and was associated with a pre-existing bundle branch block (p = 0.010) or advanced age (p = 0.023). All patients with delayed complete heart block during follow-up (n = 15, 8.7%), occurring 1 to 6 days after TASH, showed lack of retrograde atrioventricular nodal conduction after TASH (p = 0.018). None of the patients with intact retrograde conduction after TASH developed delayed complete heart block. Further risk factors for delayed block were advanced age, intraprocedural complete heart block, and prolonged QRS duration before or after TASH (p < 0.05 for all). Permanent pacemaker implantation was performed in 20 patients.

CONCLUSIONS

Measurement of intracardiac conduction during TASH improves the safety of the procedure by enabling identification of patients who are at risk of complete heart block after TASH. The duration of prophylactic temporary pacemaker backup should be prolonged up to day 6 after TASH in patients at increased risk (patients with retrograde atrioventricular block and at least 1 additional risk factor).

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.

Delayed Occurrence of Unheralded Phase IV Complete Heart Block After Ethanol Septal Ablation for Symmetric Hypertrophic Obstructive Cardiomyopathy

Ethanol septal ablation has emerged as a less invasive alternative to surgical myomectomy for treatment of asymmetric hypertrophic obstructive cardiomyopathy (ASH). The procedure has very low mortality, but high-degree AV conduction block is a frequent complication. Prior studies have documented baseline left bundle branch block and high volume of ethanol injection (greater than 4 mL) as risk factors. Complete heart block is often preceded by postprocedure conduction abnormalities and generally develops within 48 hours after ethanol ablation. We present a unique case of a patient with symmetric hypertensive hypertrophic obstructive cardiomyopathy (SHOCM) who developed phase IV complete heart block >96 hours postprocedure without preceding conduction abnormalities or other classic risk factors.

Effect of transcoronary ablation of septal hypertrophy on clinical outcome in hypertrophic obstructive cardiomyopathy associated with atrial fibrillation

BACKGROUND

Relatively few reports on the clinical impact of atrial fibrillation (AF) in hypertrophic obstructive cardiomyopathy (HOCM) are available. The aims of our study are to report the effect of transcoronary ablation of septal hypertrophy (TASH) on clinical outcome in HOCM associated with AF and to evaluate the influence of AF on symptoms and quality of life in HOCM.

PATIENT AND METHODS

In 80 consecutive patients (38 f, mean age 56 +/- 17 years) with severely symptomatic HOCM referred for interventional treatment, we analyzed the prevalence of AF based on 240 Holter ECG recordings and patients' history, retrospectively. Symptoms, quality of life, number of hospital admissions and hemodynamic performance were obtained in all patients before and after TASH. Mortality was additionally investigated by letter and telephone contact.

RESULTS

The overall prevalence of AF was 29%. Paroxysmal AF was detected in 17 pts (21.3%), persistent AF in 5 pts (6.3%). Only 1 pt (1.3%) suffered from permanent AF. Symptoms due to AF were present in 52.6% of the AF patients. Quality of life score was markedly improved after TASH (15.9 +/- 3.8 vs. 20.7 +/- 3.8, p < 0.001) with no difference between sinus rhythm and atrial fibrillation. However, hospital admissions were more frequent in the AF group (0.85 +/- 1.84 vs. 0.28 +/- 0.81, p = 0.03) in 32 +/- 13 months. AF patients suffered more often from syncope before TASH (30 +/- 70% vs. 10 +/- 30%, p = 0.008). Two patients with sinus rhythm at baseline died after 32 +/- 13 months from cardiovascular cause.

CONCLUSIONS

Atrial fibrillation is the major cardiac arrhythmia in severe HOCM. The majority of AF patients demonstrate AF specific symptoms. The paroxysmal type of atrial fibrillation dominates by far. Both patients with and without atrial fibrillation showed similar quality of life with marked improvement after TASH.

Impact of Ethanol Dosing on the Long-Term Outcome of Alcohol Septal Ablation for Obstructive Hypertrophic Cardiomyopathy A Single-Center, Prospective, and Randomized Study

BACKGROUND

The impact of ethanol dose on the long-term outcome of alcohol septal ablation (ASA) for obstructive hypertrophic cardiomyopathy was investigated.

METHODS AND RESULTS

Fifty-four patients (age 24-82 years; 65% women) undergoing ASA were randomized into 2 groups according to the dose of injected ethanol: Group A 1-2 ml, Group B >2 ml. Clinical and echocardiographic data were obtained at baseline and during follow-up. The volume of ethanol injected was 1.50+/-0.4 and 2.60+/-0.6 ml (p<0.001) with a subsequent peak of creatine kinase-MB of 2.25+/-1.00 and 2.62+/-1.57 microkat/L (p=0.02) in Groups A and B, respectively. The median follow-up was 39 (range 6-72) months after ASA, during which 1 patient died and 1 repeat procedure was necessary in both groups of patients. Both groups had a significant and similar improvement in outflow pressure gradient, dyspnea (New York Heart Association functional class) and angina pectoris (Canadian Cardiovascular Society class) (p<0.001). There was a significant decrease in the left ventricular ejection fraction (LVEF) in Group B (81+/-7 vs 75+/-7%; p=0.002), but not in Group A (80+/-7 vs 79+/-7%; p=0.67). Thinning of the basal septum was more pronounced in Group B than in Group A (9.3+/-5.7 vs 6.6+/-3.4 mm; p=0.04).

CONCLUSIONS

A lower dose of ethanol injected into the target septal branch reduces both the size of necrosis and subsequent thinning of the basal septum, and preserves LVEF during long-term follow-up. Moreover, the low dose (1-2 ml) is as safe and as hemodynamically efficacious as higher doses.

Radiofrequency catheter septal ablation for hypertrophic obstructive cardiomyopathy in childhood

Two patients, a 5 year old boy with progressive hypertrophic obstructive cardiomyopathy and increasing symptoms despite appropriate pharmacologic therapy and an 11 year old girl with symptoms of tiredness and peak instantaneous LVOT gradient of 80 and 90 mmHg respectively were considered for radiofrequency catheter septal ablation, to relieve the left ventricular outflow tract obstruction. Via a femoral arterial approach, the His bundle was initially plotted and marked using the LocaLisa navigation system. Subsequently, using a cooled tip catheter a series of lesions was placed in the hypertrophied septum, commencing distally in the ventricle and proceeding towards the aortic valve, taking care to stay away from the His bundle. The procedure was deemed to be completed when the entire extent of the hypertrophied septum had been treated. In the boy the procedure was complicated by two episodes of ventricular fibrillation, requiring DC cardioversion, but without any neurologic sequelae. The peak to peak gradient between left ventricle and aorta was 50 mmHg and 60 mmHg respectively pre-ablation, and remained unchanged immediately after. Both patients were discharged from the hospital 48 hours later. Serial measurement of serum Troponin T and CK-MB isoenzyme confirmed significant myocardial necrosis. Follow-up echocardiography at 7 days and at 6 weeks post-ablation respectively confirmed a beneficial hemodynamic result, with reduction of left ventricular outflow obstruction and relief of symptoms. In young children, in whom alcohol induced septal ablation is not an option, radiofrequency catheter ablation offers an alternative to surgery, with the benefits of repeatability and a lower risk of procedure-related permanent AV block.

Catheter-based septal ablation for symptomatic hypertrophic obstructive cardiomyopathy: follow-up results of the TASH-registry of the German Cardiac Society

INTRODUCTION

In late 1997, the German Cardiac Society set up a multicenter registry to evaluate the acute and mid-term course of all patients (pts.) treated with septal ablation for symptomatic hypertrophic obstructive cardiomyopathy (HOCM). An analysis of the acute results has already been published. We now report on the mid-term course (3-6 months) of 242 pts. registered through September 1999.

RESULTS

Follow-up was 92% complete (n=222). During follow-up (mean: 4.9+/-2.3 months), an additional 3 pts. died (in-hospital mortality: 3 pts.). A satisfactory clinical effect was reported by 195 pts. (88%); 27 pts. (12%) remained in NYHA classes III and IV. Overall symptomatic improvement (NYHA class: from 2.8+/-0.7 to 1.7+/-0.7) paralleled the outflow gradient (LVOTG) reduction which was further accentuated as compared with the acute result (Doppler measurement at rest: from 57+/-31 to 25+/-25 mmHg to 20+/-21 mmHg; with provocation: from 107+/-53 to 49+/-40, to 44+/-40 mmHg, p<0.001, resp.). Left atrial (LA) diameter (from 46+/-8 to 44+/-7 mm) and septal thickness (from 20+/-5 to 15+/-5 mm; p<0.001, resp.) were also reduced. Comparing the methods for target vessel selection (i.e., with contrast echo monitoring vs pressurefluoroscopy guidance), at followup clinical improvement and hemodynamic measurements were comparable.

CONCLUSION

Clinical success can be achieved by septal ablation, both with the echocontrast guided and gradient-fluoroscopy guided method, in 88% of highly symptomatic HOCM pts. At mid-term follow-up, symptoms, left atrial size and septal thickness are reduced, and outflow gradients are further improved as compared to the acute result.

Management of pediatric hypertrophic cardiomyopathy

PURPOSE OF REVIEW

As the underlying genetic basis of hypertrophic cardiomyopathy is being characterized, there has been increasing recognition of the wide spectrum and variable evolution of this disease within the pediatric age range. This review outlines recent evidence relevant to the diagnosis, management, and prognosis of hypertrophic cardiomyopathy specific to children and adolescents.

RECENT FINDINGS

Studies of putative causal genes are leading to the discovery of factors affecting the variability of phenotypic expression and possible avenues for new therapies. Nonetheless, the use of genetic testing currently remains for research purposes only. Echocardiography is the primary means for evaluation, with an increasing focus on diastolic performance. Useful prognostic information can be obtained from the safe performance of cardiopulmonary stress testing. Sudden death can occur in children, although the risk factors are likely different than in adults. The role and mechanisms for possible ischemia remain controversial, and likely differ between individuals. Activity restrictions are recommended, with medical therapy reserved for those who are symptomatic. For those with important left ventricular outflow obstruction, surgical myectomy may be indicated, with little current role for alcohol septal ablation. Advances in implantable defibrillators now make this therapy feasible in younger children.

SUMMARY

There are important differences from adults in the approach to the diagnosis and management of hypertrophic cardiomyopathy in children and adolescents. Care regarding prognostication and therapy must be taken given the potential life-long implications.

Technology Insight: transcoronary ablation of septal hypertrophy

Among patients with hypertrophic cardiomyopathy, 5-10% have outflow tract obstruction that results in symptoms refractory to medical therapy. Surgical myectomy has been the gold standard for treating these patients since the 1960s. In the past 10 years, however, alcohol septal ablation has emerged as an alternative procedure. There is growing evidence to indicate that this technique is comparable to surgical myectomy with respect to hemodynamic and functional improvement, although no randomized comparative studies exist to date. The procedure consists of injecting as mall volume of alcohol into a septal perforator under balloon occlusion,preferably after localization of the target septal branch by myocardial contrast echocardiography. Relief of the gradient is instantaneous in about 90% of patients, and further decreases might occur over time. Functional class, exercise capacity and quality of life have been shown to be improved during follow-up. The main risk of the technique is atrioventricular block, which occurs in about 10% of patients. Because of this side-effect and a steep learning curve, the technique should be performed only by experienced operators and on carefully selected patients.

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 myocardial contrast echocardiographic quantification of risk area for predicting postprocedural complications in patients undergoing septal ethanol ablation for obstructive hypertrophic cardiomyopathy

Septal ethanol ablation (SEA) is an alternative to surgical myectomy in patients who have drug-refractory obstructive hypertrophic cardiomyopathy. However, permanent atrioventricular conduction block is seen more frequently with SEA. To determine whether septal infarction risk area (SIRA) predicts outcome in patients who have obstructive hypertrophic cardiomyopathy and are undergoing SEA, we evaluated 51 patients (mean age 60 +/- 16, 53% women) who had a successful SEA at Toronto General Hospital (November 1998 to June 2003). Intracoronary myocardial contrast echocardiography that targeted the contact area between the septum and the anterior mitral leaflet was performed before ethanol injection. End-systolic myocardial contrast echocardiographic frames were color coded for better delineation of contrast borders, and myocardial contrast echocardiographic area was calculated by planimetry. Patients were assigned to 1 of 2 groups by median SIRA value (3.51 cm(2), range 0.4 to 7.8). The 2 groups did not differ significantly in age, medication before SEA, electrocardiographic characteristics, left ventricular function, left atrial diameter, volume of intracoronary ethanol injected, peak creatine kinase after ablation, and baseline and follow-up left ventricular outflow tract gradients at rest. Patients in the large SIRA group had greater hypertrophy and a larger septal artery than did patients in the small SIRA group. In the small SIRA group, 3 patients (11.5%) had pacemaker implantation; in the large SIRA group, 12 patients (48.0%) had complications after SEA (pacemaker in 5 patients, implantable defibrillator in 5 patients, death in 2 patients; p = 0.008). We conclude that patients who have hypertrophic cardiomyopathy with a small, well-localized SIRA benefit similarly from SEA as patients who have a larger SIRA but with significantly fewer serious complications.