Nonsurgical septal reduction for hypertrophic obstructive cardiomyopathy: outcome in the first series of patients

Left ventricular catheter ablation using direct, intramural ethanol injection in swine

INTRODUCTION

Limitations in lesion volume and particularly lesion depth may negatively effect the efficacy of catheter ablation procedures using radiofrequency energy. This study evaluated the safety and efficacy of myocardial ablation using direct intramural injection of ethanol with a novel injection catheter system.

METHODS

Left ventricular lesions were performed in 9 male swine (80-85 pounds); two animals were studied 6 weeks following anterior infarction produced by agarose gel embolization. An 8 Fr deflectable catheter equipped with a 27 gauge adjustable depth, retractable needle was directed to the LV using a retrograde aortic approach. Lesion deployment was guided by fluoroscopy and intracardiac echocardiography (ICE). Lesion characteristics were assessed with ICE imaging and pathologic analysis.

RESULTS

Ethanol lesions were confined to the tissue directly adjacent to the injection port. Lesions were intramural with no evidence of overlying thrombus. Lesions delivered with a single port injection needle in normal myocardium (n = 24) averaged 1910 +/- 1066 mm(3) with a depth of 8.9 +/- 3.3 mm. Lesions directed to infarct border zones (n = 4) averaged 929 +/- 882 mm(3) with a depth of 4.3 +/- 2.8 mm. Lesions were immediately evident on ICE imaging, and were visualized by increased echo density and tissue swelling. Pathological analysis revealed homogenous lesions with intramural hemorrhage and contraction band necrosis.

CONCLUSIONS

Myocardial catheter ablation using direct ethanol injection is feasible, and relatively large and deep intramural lesions can be delivered, even in the infarct border zone. This technique may prove useful in ablation of arrhythmia substrates that are deep to the endocardial surface.

Hypertrophic cardiomyopathy: management issues in the new millennium

Hypertrophic cardiomyopathy is an inherited cardiac disorder. Sudden cardiac death frequently occurs in otherwise healthy individuals, and accounts for nearly 35% of all sudden deaths within this age group. Although symptoms occur commonly, they often go unreported. Despite this, a degree of functional limitation is often seen on objective assessment. Management of hypertrophic cardiomyopathy is aimed at relieving symptoms, identifying and treating those individuals at increased risk of sudden death, and screening family members.

Regional overexpression of insulin-like growth factor-I and transforming growth factor-beta1 in the myocardium of patients with hypertrophic obstructive cardiomyopathy

OBJECTIVE

Hypertrophic obstructive cardiomyopathy has been proposed to be the result of gene mutations of contractile proteins. However, we have previously shown significant elevation of insulin-like growth factor-I (IGF-I) and transforming growth factor-beta1 (TGF-beta1) at the messenger RNA, protein, and receptor levels in patients with hypertrophic obstructive cardiomyopathy when compared with myocardium from patients without this disorder. We hypothesized that this growth factor overexpression is a regional phenomenon. To test this hypothesis, we compared levels of IGF-I and TGF-beta1 in hypertrophic and nonhypertrophic myocardium within the same group of patients with hypertrophic obstructive cardiomyopathy.

METHODS

Two biopsy specimens were obtained from each patient undergoing septal myectomy for severely symptomatic hypertrophic obstructive cardiomyopathy, from hypertrophied septum and from nonhypertrophied myocardium (8 patients in total). Clinical data were prospectively recorded. Messenger RNA levels for growth factor were quantified by means of multiplex reverse transcriptase-polymerase chain reaction, expressed as a densitometric ratio of growth factor/glyceraldehyde-3-phosphate dehydrogenase. Protein levels were quantified by means of chemiluminescent slot blot analysis. Growth factor proteins were used to generate a standard curve.

RESULTS

IGF-I messenger RNA and protein levels in hypertrophic myocardium were 2.6 and 2.9 times greater, respectively, than in nonhypertrophic myocardium of the same patients (both P <.01). TGF-beta 1 messenger RNA and protein levels in the hypertrophic myocardium were 2.5 and 2.8 times greater, respectively, than the levels in the nonhypertrophied myocardium (both P <.01). There was a significant correlation between the IGF-I protein ratio (hypertrophic/nonhypertrophic myocardium) and the inducible left ventricular outflow tract gradients measured at cardiac catheterization (r = 0.77, P =.025).

CONCLUSIONS

Myocardial overexpression of IGF-I and TGF-beta1 is a regional phenomenon in patients with hypertrophic obstructive cardiomyopathy and is likely involved in the pathogenesis of the disorder.

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.

Comparison of ethanol septal reduction therapy with surgical myectomy for the treatment of hypertrophic obstructive cardiomyopathy

OBJECTIVES

This study was designed to compare the hemodynamic efficacy of nonsurgical septal reduction therapy (NSRT) by intracoronary ethanol with standard therapy (surgical myectomy) for the treatment of hypertrophic obstructive cardiomyopathy (HOCM).

BACKGROUND

Nonsurgical septal reduction therapy has gained interest as a new treatment modality for patients with drug-refractory symptoms of HOCM; however, its benefits in comparison to surgery are unknown.

METHODS

Forty-one consecutive NSRT patients at Baylor College of Medicine with one-year follow-up were compared with age- and gradient-matched septal myectomy patients at the Mayo Clinic. All patients had left ventricular outflow obstruction with a resting gradient > or =40 mm Hg and none had concomitant procedures.

RESULTS

There were no baseline differences in New York Heart Association class, severity of mitral regurgitation, use of cardiac medications or exercise capacity. One death occurred during NSRT because of dissection of the left anterior descending artery. At one year, all improvements in both groups were similar. After surgical myectomy, more patients were on medications (p < 0.05) and there was a higher incidence of mild aortic regurgitation (p < 0.05). After NSRT, the incidence of pacemaker implantation for complete heart block was higher (22% vs. 2% in surgery; p = 0.02). However, seven of the nine pacemakers in the NSRT group were implanted before a modified ethanol injection technique and the use of contrast echocardiography.

CONCLUSIONS

Nonsurgical septal reduction therapy resulted in a significantly higher incidence of complete heart block, but the risk was reduced with contrast echocardiography and slow ethanol injection. Surgical myectomy resulted in a significantly higher incidence of mild aortic regurgitation. Nonsurgical septal reduction therapy, guided by contrast echocardiography, is an effective procedure for treating patients with HOCM. The hemodynamic and functional improvements at one year are similar to those of surgical myectomy.

[Therapeutic approaches in symptomatic hypertrophic obstructive cardiomyopathy]

Hypertrophic cardiomyopathy is a complex and heterogeneous disease. Although most patients experience just a few symptoms, and have a good prognosis, there are others whose symptoms are severe and progressive, determined by different pathophysiological elements such as diastolic dysfunction, myocardial ischemia, arrhythmias and subaortic obstruction. Approximately 20-30% of hypertrophic cardiomyopathy patients develop an intraventricular dynamic gradient, which in some cases, is responsible for severe symptoms which are ameliorated once the obstruction is reduced. In many cases the symptoms can be controlled with medical treatment which includes betablockers, calcium-channel antagonists and dysopiramide, but some patients will still experience severe and refractory symptoms. This subgroup of patients, which represent approximately 5-10% of patients with hypertrophic cardiomyopathy, can be problematic from a management perspective. For many years, septal myectomy and/or mitral valve replacement offered the only effective alternative therapy for these patients. However, the high rates of morbidity and mortality associated with these procedures have necessitated the search for new and less invasive procedures such as ventricular pacing and percutaneous septal ablation. Although the initial results with sequential pacing were encouraging, further studies have suggested a significant placebo effect, which makes its application controversial. In the last 5 years selective embolization of the septal artery precipitating a localized myocardial infarction has been utilized to reduce the subaortic gradient. The potential indications and efficacy of these new forms of treatment, like ventricular pacing and percutaneous septal ablation, are presently under evaluation and are the main subject of this review. Medical treatment, with either beta-blockers, calcium channel antagonists or dysopiramide constitutes the first therapeutic step. Surgery, while alleviating the subaortic obstruction and reducing the intraventicular pressure and mitral insufficiency, produces important and long-lasting symptomatic and functional improvement in most of these patients, and it continues to be an important therapeutic alternative in these cases. If the first results with sequential pacemaker implants were encouraging, today it is alluded to an important placebo effect that causes its application to be controversial. In the last 5 years the path has been made in the creation of a septal infarction located through the embolization of the septal branches to reduce the gradient.

Pressure-guided nonsurgical myocardial reduction induced by small septal infarctions in hypertrophic obstructive cardiomyopathy

OBJECTIVES

We sought to assess the safety and efficacy of pressure-guided nonsurgical myocardial reduction (NSMR) with the induction of small septal infarctions in patients with hypertrophic obstructive cardiomyopathy (HOCM).

BACKGROUND

Nonsurgical myocardial reduction has been shown to decrease left ventricular outflow tract (LVOT) obstruction and to improve symptoms in patients with HOCM. Infarct sizes differ considerably among studies published so far.

METHODS

In 50 patients, the LVOT gradient was invasively determined at the time of the intervention, four to six months (n = 49) and 12 to 18 months (n = 25) after NSMR. New York Heart Association functional class and quality of life were assessed by using a standard questionnaire. Exercise capacity was tested by spiro-ergometry. Left ventricular (LV) mass was determined by electron beam computed tomography.

RESULTS

Small septal infarctions (mean creatine kinase value 413 +/- 193 U/l) resulted in a sustained decrease in LVOT gradients, from 80 +/- 33 to 18 +/- 17 mm Hg after four to six months (p < 0.001, n = 49) and to 17 +/- 15 mm Hg (p < 0.001, n = 25) after 12 to 18 months. Nonsurgical myocardial reduction was followed by a decrease in LV hypertrophy, which was associated with a sustained increase in exercise capacity, as well as improvement in quality of life.

CONCLUSIONS

Pressure-guided NSMR inducing small septal infarctions was sufficient to result in a sustained decrease in LVOT obstruction and to improve symptoms. The incidence of complications, such as complete heart block with necessary permanent pacemaker implantation (<10%), seems to be diminished by minimizing the infarct size.

Usefulness of selective myocardial contrast echocardiography in percutaneous transluminal septal myocardial ablation: a case report

A 67-year-old woman with hypertrophic obstructive cardiomyopathy that was refractory to medical treatment underwent percutaneous transluminal septal myocardial ablation (PTSMA). The septal branch supplying the myocardium involved in the left ventricular outflow tract (LVOT) obstruction was identified by selective myocardial contrast echocardiography (MCE). MCE for the third and largest septal branch opacified the right side of the mid-septal myocardium and MCE for the second septal branch opacified the right side of the basal portion of the septal myocardium. Finally, contrast agent was injected into the first, small branch, which opacificied the myocardium protruding into the LVOT. Subsequently, septal myocardial ablation for this vessel with intracoronary alcohol was performed, followed by a reduction of the LVOT gradient and successful, dramatic improvement in the patient's clinical condition. Selective MCE was very useful to identify the appropriate septal branch for PTSMA and enabled maximal effect of this treatment with minimal myocardial damage.

Percutaneous transluminal alcohol septal myocardial ablation after aortic valve replacement

When left ventricular outflow tract obstruction develops after aortic valve replacement, few treatment choices have been available until now. We present a patient with prior aortic valve replacement who developed left ventricle outflow tract obstruction that was successfully treated with a percutaneous transcoronary myocardial septal alcohol ablation. This technique is a useful tool for the treatment of obstructive hypertrophic cardiomyopathy, especially in those patients with prior heart surgery.

Antiarrhythmic drug, cibenzoline, can directly improve the left ventricular diastolic function in patients with hypertrophic cardiomyopathy

The effect of cibenzoline on left ventricular diastolic function was investigated in patients with hypertrophic cardiomyopathy (HCM). Before and 2 h after an oral administration of 200 mg of cibenzoline, echocardiographic, apexcardiographic and gated radionuclide angiographic studies were performed in 12 patients with hypertrophic obstructive cardiomyopathy (HOCM) and 7 with hypertrophic nonobstructive cardiomyopathy (HNCM). After administration of cibenzoline, the left ventricular pressure gradient decreased from 96+/-33 mmHg to 29+/-22 mmHg (<0.0001). Fractional shortening decreased from 53.3+/-7.5 to 45.4+/-6.2% (p=0.0008) in patients with HOCM and from 49.9+/-8.7 to 40.9+/-7.5% (p=0.0039) in patients with HNCM. On the other hand, E-wave velocity increased and A-wave velocity decreased in both groups. The time between the second heart sound and O point was shortened from 253+/-53 to 176+/-21 ms (p<0.0001) in patients with HOCM and from 245+/-54 to 185+/-44 ms (p=0.0050) in patients with HNCM. The time to peak filling rate was shortened from 248+/-79 to 190+/-40 ms (p=0.0072) in patients with HOCM and from 218+/-33 to 163+/-26 ms (p=0.0052) in patients with HNCM. These results indicate that in patients with HCM, cibenzoline suppresses left ventricular systolic function, but can markedly improve left ventricular diastolic dysfunction through its direct action.

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.

Echocardiographic insights into the mechanisms of relief of left ventricular outflow tract obstruction after nonsurgical septal reduction therapy in patients with hypertrophic obstructive cardiomyopathy

OBJECTIVES

We sought to evaluate the mechanisms by which nonsurgical septal reduction therapy (NSRT) reduces left ventricular outflow tract (LVOT) obstruction in patients with hypertrophic obstructive cardiomyopathy (HOCM) both acutely and on a long-term basis.

BACKGROUND

NSRT reduces LVOT obstruction in patients with HOCM and leads to symptomatic improvement. The mechanisms involved, however, are not well studied.

METHODS

An initial group of 30 HOCM patients (age 46 +/- 17, 16 women) who underwent NSRT had echocardiographic studies performed at baseline and six months after the procedure. Measurements included LVOT diameter, end-diastolic distance between the anterior mitral leaflet and interventricular septum, septal base function and the angle between LV systolic flow and the protruding mitral leaflets. In addition, pulse Doppler recordings at a point 2.5 cm apical to the mitral valve were acquired and analyzed for peak and mean ejection velocity, peak acceleration rate and the ratio of acceleration time to ejection time (AT/ET).

RESULTS

Significant changes were observed after the procedure, with widening in the LVOT, thinning and akinesis of the septal base, decrease in the angle between LV systolic flow and the protruding mitral leaflets, a decrease in peak acceleration rate and an increase in AT/ET. All of these variables had significant relations with the decrease in LVOT obstruction (r = 0.5 to 0.79, p < 0.01). These correlations were then evaluated in a test group of 15 patients who underwent echocardiographic examinations at baseline, acutely in the catheterization laboratory with ethanol injection and at six weeks post NSRT. Acute changes in peak acceleration rate (r = 0.65) and AT/ET (r = 0.73) related significantly (p < 0.01) to the decrease in LVOT obstruction with ethanol. At six weeks, changes similar to those noted in the initial group were observed in LVOT geometry, the angle between LV systolic flow and the protruding mitral leaflets, peak acceleration rate and AT/ET. In both populations combined, these parameters accounted for 72% to 77% of the variance in gradient reduction.

CONCLUSIONS

Changes in LV ejection dynamics and septal base function account in part for the acute relief of LVOT gradient after NSRT. The long-term relief of obstruction is dependent on remodeling of LVOT as well as the changes in LV ejection.

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

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

Use of implantable pacemakers and implantable defibrillators in hypertrophic cardiomyopathy

Recent data have emerged to help guide the use of implantable pacemakers and implantable defibrillators in patients who have hypertrophic cardiomyopathy (HCM). Controlled studies of the use of dual chamber pacemakers to treat outflow tract obstruction in HCM have shown little benefit, and have raised the possibility that earlier favorable reports were demonstrating an element of placebo effect. In particular, there is no recent support for earlier claims of regression of ventricular hypertrophy from chronic dual chamber pacing. Several reports have added to our understanding of the risk factors for sudden death in HCM. A normal blood pressure response to exercise appears to identify a subset of patients at low risk for sudden death. In a recent study of a large number of HCM patients, the risk of sudden death was found to be directly proportional to the extent of left ventricular hypertrophy. There is accumulating evidence that the implantable defibrillator is highly effective in terminating malignant ventricular arrhythmias in HCM patients, and HCM patients thought to be at significant risk for sudden death should be offered defibrillator implantation.

Targeting percutaneous transluminal septal ablation for hypertrophic obstructive cardiomyopathy by intraprocedural echocardiographic monitoring

BACKGROUND

Percutaneous septal ablation has evolved as an alternative to surgery for reducing symptoms and outflow gradients in patients with hypertrophic obstructive cardiomyopathy. Intraprocedural echo-cardiographic imaging can improve clinical and hemodynamic results. Growing experience with this method has additionally shown that threatening necrosis of the myocardium distant from the septal target region can be detected.

METHODS AND RESULTS

Percutaneous septal ablation was performed in 162 patients (80 women, 82 men; aged 54.1 +/- 15.5 years); 131 of whom were targeted by intraprocedural myocardial contrast echocardiography. In 11 patients (7%), an atypical target vessel or a perfusion area distant from the expected septal target region was detected, leading to a target vessel change. Permanent pacing was necessary in 14 patients (9%). Three patients (2%) died. After 3 months, the mean New York Heart Association functional class was reduced in the returning 159 patients from 2.8 +/- 0.5 to 1.3 +/- 1.0 (P <.0001) along with a gradient reduction from 77 +/- 35 to 12 +/- 22 mm Hg at rest, and from 147 +/- 43 to 44 +/- 45 mm Hg with provocation (P < .0001 each). The main reason for unsatisfactory gradient reduction was suboptimal scar placement in the patients treated before the introduction of intraprocedural myocardial contrast echocardiography.

CONCLUSIONS

Percutaneous septal ablation is an effective nonsurgical technique for reducing symptoms and outflow gradients in hypertrophic obstructive cardio-myopathy. Echocardiographic guidance adds substantially to safety and efficacy of the procedure and should therefore be considered routinely.

Systolic anterior motion begins at low left ventricular outflow tract velocity in obstructive hypertrophic cardiomyopathy

OBJECTIVES

The purpose of this study was to determine whether the dynamic cause for mitral systolic anterior motion (SAM) is a Venturi or a flow drag (pushing) mechanism.

BACKGROUND

In obstructive hypertrophic cardiomyopathy (HCM), if SAM were caused by the Venturi mechanism, high flow velocity in the left ventricular outflow tract (LVOT) should be found at the time of SAM onset. However, if the velocity was found to be normal, this would support an alternative mechanism.

METHODS

We studied with echocardiography 25 patients with obstructive HCM who had a mean outflow tract gradient of 82 +/- 6 mm Hg. We compared mitral valve M-mode echocardiogram tracings with continuous wave (CW) and pulsed wave (PW) Doppler tracings recorded on the same study. A total of 98 M-mode, 159 CW, and 151 PW Doppler tracings were digitized and analyzed. For each patient we determined the LVOT CW velocity at the time of SAM onset. This was done by first determining the mean time interval from Q-wave to SAM onset from multiple M-mode tracings. Then, CW velocity in the outflow tract was measured at that same time interval following the Qwave.

RESULTS

Systolic anterior motion began mean 71 +/- 5 ms after Q-wave onset. Mean CW Doppler velocity in the LVOT at SAM onset was 89 +/- 8 cm/s. In 68% of cases SAM began before onset of CW and PW Doppler LV ejection.

CONCLUSIONS

Systolic anterior motion begins at normal LVOT velocity. At SAM onset, though Venturi forces are present in the outflow tract, their magnitude is much smaller than previously assumed; the Venturi mechanism cannot explain SAM. These velocity data, along with shape, orientation and temporal observations in patients, indicate that drag, the pushing force of flow, is the dominant hydrodynamic force that causes SAM.

Coronary stent implantation in a septal perforator artery: case report and review of the literature

Septal perforator arteries play an important role in the blood supply of the anterior interventricular septum. Their intramyocardial course makes them inaccessible for coronary bypass revascularization. Although modern catheter-based techniques might be superior to coronary bypass grafting in offering the most complete revascularization in selected patient populations, a systematic review of the literature revealed a paucity of data regarding the outcome of these patients. The present report describes coronary stent implantation in a dominant septal perforator artery and the analysis of the anatomic relationship between the stent and the intraventricular septum using a new imaging technique, catheter-based intracardiac ultrasound.

Nonsurgical septal reduction therapy for hypertrophic obstructive cardiomyopathy: one-year follow-up

OBJECTIVE

The objective of this study is to evaluate the one-year outcome of the first 50 patients who underwent nonsurgical septal reduction for symptomatic hypertrophic obstructive cardiomyopathy at our institution.

BACKGROUND

Left ventricular outflow tract obstruction is an important determinant of clinical symptoms in patients with hypertrophic obstructive cardiomyopathy. Nonsurgical septal reduction is a new therapy that has been shown to result in left ventricular outflow tract gradient reduction and resolution of symptoms immediately after the procedure and on midterm follow-up.

METHODS

Fifty patients with hypertrophic obstructive cardiomyopathy who underwent nonsurgical septal reduction at our institution and completed 1-year follow-up are described. Complete history, physical examination, two-dimensional echocardiography with Doppler and exercise treadmill testing have been analyzed.

RESULTS

The mean age of the study group was 53 +/- 17 years. All patients had refractory symptoms before enrollment. Ninety-four percent had class III or IV New York Heart Association class symptoms at baseline compared to none at 1 year (p < 0.001). The exercise duration increased by 136 s at 1 year (p < 0.021). Only 20% of patients were either receiving beta-blockers or calcium-channel blockers on follow-up. The resting left ventricular outflow tract gradient decreased from 74 +/- 23 mm Hg to 6 +/- 18 mm Hg (p < 0.01) and from 84 +/- 28 mm Hg to 30 +/- 33 mm Hg (p < 0.01) in patients with dobutamine-provoked gradient at one year. These changes are associated with decreased septal thickness and preserved systolic function.

CONCLUSION

Nonsurgical septal reduction therapy is an effective therapy for symptomatic patients with hypertrophic obstructive cardiomyopathy with persistence of the favorable outcome up to one year after the procedure.

Magnitude of left ventricular hypertrophy and risk of sudden death in hypertrophic cardiomyopathy

BACKGROUND

Sudden death is known to be a possible consequence of hypertrophic cardiomyopathy. Quantification of the risk of sudden death, however, remains imprecise for most patients with this disease.

METHODS

We assessed the relation between the magnitude of left ventricular hypertrophy and mortality in 480 consecutive patients with hypertrophic cardiomyopathy. The patients were categorized into five subgroups according to maximal wall thickness: 15 mm or less, 16 to 19 mm, 20 to 24 mm, 25 to 29 mm, and 30 mm or more. Their ages ranged from 1 to 89 years (median, 47).

RESULTS

Over a mean follow-up period of 6.5 years, 65 of the 480 patients (14 percent) died: 23 suddenly, 15 of heart failure, and 27 of noncardiac causes or stroke. The risk of sudden death increased progressively and in direct relation to wall thickness (P=0.001), ranging from 0 per 1000 person-years (95 percent confidence interval, 0 to 14.4) for a wall thickness of 15 mm or less to 18.2 per 1000 person-years (95 percent confidence interval, 7.3 to 37.6) for a wall thickness of 30 mm or more and almost doubling from each wall-thickness subgroup to the next. The cumulative risk 20 years after the initial evaluation was close to zero for patients with a wall thickness of 19 mm or less but almost 40 percent for wall thicknesses of 30 mm or more. As compared with the other subgroups, patients with extreme hypertrophy were the youngest (mean age, 31 years), and most (41 of 43) had mild symptoms or no symptoms; of the 12 patients who were less than 18 years old at the initial evaluation, 5 died suddenly.

CONCLUSIONS

In hypertrophic cardiomyopathy, the magnitude of hypertrophy is directly related to the risk of sudden death and is a strong and independent predictor of prognosis. Young patients with extreme hypertrophy, even those with few or no symptoms, appear to be at substantial long-term risk and deserve consideration for interventions to prevent sudden death. The majority of patients with mild hypertrophy are at low risk and can be reassured regarding their prognosis.

New treatment methods for patients with hypertrophic obstructive cardiomyopathy

The past decade has witnessed significant advancements in the treatment of patients with refractory symptoms due to hypertrophic obstructive cardiomyopathy. In this publication, we will review the impact of dual-chamber pacing and nonsurgical septal reduction therapy with ethanol on the outcome of these patients. Both therapies have been shown to result in significant reductions in the left ventricular outflow gradient, which was an entry criterion in all the reported studies, along with symptomatic relief from symptoms of angina and dyspnea on midterm follow-up. Studies currently are under way to compare dual-chamber pacing and nonsurgical septal reduction therapy with myotomy-myomectomy, which is considered to be the standard of care in these patients.

Left ventricular opacification during selective intracoronary injection of echocardiographic contrast in patients with hypertrophic cardiomyopathy

Percutaneous alcohol ablation of the interventricular septum via the first septal perforator branch of the left anterior descending artery can successfully treat dynamic left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy. Increasingly, echocardiographic contrast agents are used before alcohol injection to identify the perfusion bed of the septal perforator vessels. This study describes the unexpected opacification of the left ventricular cavity in three of five consecutive patients following selective injection of the first septal perforator with Optison. This case study demonstrates that direct communication between the first septal perforator vessel and the left ventricle is common, an observation that may have considerable relevance to the technique of alcohol septal reduction.

Percutaneous transluminal septal myocardial ablation for hypertrophic obstructive cardiomyopathy: long term follow up of the first series of 25 patients

OBJECTIVE

To determine the long term outcome in patients treated with percutaneous transluminal septal myocardial ablation (PTSMA) for hypertrophic obstructive cardiomyopathy (HOCM).

DESIGN AND SETTING

Observational, single centre study.

PATIENTS

25 patients (13 women, 12 men, mean (SD) age 54.7 (15.0) years) with drug treatment resistant New York Heart Association (NYHA) class 2.8 (0. 6) symptoms attributed to a high left ventricular outflow gradient (LVOTG) and a coronary artery anatomy suitable for intervention.

INTERVENTION

PTSMA by injection of 4.1 (2.6) ml of alcohol (96%) into 1.4 (0.6) septal perforator arteries to ablate the hypertrophied interventricular septum.

OUTCOME MEASURES

During in-hospital follow up, enzyme rise, the frequency of atrioventricular conduction lesions requiring permanent DDD pacing, and in-hospital mortality were assessed. Long term follow up (30 (4) months, range 24-36 months) included symptoms, echocardiographic measurements of left atrial and left ventricular dimensions and function, and LVOTG.

RESULTS

Mean postinterventional creatine kinase rise was 780 (436) U/l. During PTSMA 13 patents developed total heart block, permanent pacing being necessary in five of them. One 86 year old patient died from ventricular fibrillation associated with intensive treatment (beta mimetic and theophylline) for coexistent severe obstructive airway disease. After three months, three patients underwent re-PTSMA because of a dissatisfactory primary result, leading to LVOTG elimination in all of them. During long term follow up, LVOTG showed sustained reduction (3 (6) mm Hg at rest and 12 (19) mm Hg with provocation) associated with stable symptomatic improvement (NYHA class 1.2 (1.0)) and without significant global left ventricular dilatation.

CONCLUSIONS

PTSMA is an effective non-surgical technique for reduction of symptoms and LVOTG in HOCM. Prospective, long term observations of larger populations are necessary in order to determine the definitive significance of the procedure.

Apical hypertrophic cardiomyopathy associated with life-threatening paroxysmal atrial flutter with a slow ventricular response: a case report

A 58-year-old male patient had apical hypertrophic cardiomyopathy (HCM) associated with a life-threatening tachycardia due to atrial flutter. Following palpitation and dyspnea for 2-3 h, he became unconscious because of circulatory catastrophe, but was fully resuscitated. An electrocardiogram recorded just before the loss of consciousness revealed atrial flutter at a rate of 260 beats/min with a 2:1 ventricular response. He was diagnosed as having apical HCM based on the echocardiographic and left ventriculographic findings. Atrial stimulation at a rate of 150 pacings/min for 1 min caused a marked drop in systemic systolic blood pressure from 170 to 120 mmHg. The patient was treated with 150 mg of cibenzoline per day to prevent supraventricular tachyarrhythmias and to improve left ventricular diastolic function. At the time of the recent follow-up at 2 and a half years, he felt quite well.

Percutaneous transluminal septal myocardial ablation

Percutaneous transluminal septal myocardial ablation (PTSMA) is a new, investigational, catheter-based treatment for severely symptomatic, medically refractory hypertrophic obstructive cardiomyopathy. A balloon catheter is used to cannulate and isolate the first or second septal perforator coronary artery. Following balloon inflation and intracoronary myocardial contrast echocardiography, ethyl alcohol is injected through the catheter lumen to cause proximal interventricular septum infarction and relief of outflow tract obstruction with improved patient symptoms. Septal scarring and thinning with reductions in the outflow tract gradients ensues over the following 6 to 12 weeks. Most patients have symptomatic improvement, at least moderate reductions in outflow tract gradients, and possibly improvement in exercise capacity. The most common procedural complication is the development of high-grade atrioventricular block necessitating implantation of a permanent pacemaker in 25% of patients. Compared with surgical myectomy, PTSMA has the advantage of being minimally invasive, easily repeated, and with relatively low major morbidity/mortality risk for patients with comorbid conditions. The findings from recently initiated international registries will be helpful in assessing the overall success and complication rates with PTSMA.

Dual chamber pacing for patients with hypertrophic obstructive cardiomyopathy: a clinical perspective in 2000

In some patients with hypertrophic cardiomyopathy, the dynamic left ventricular outflow tract obstructive gradient results in exercise-limiting symptoms of dyspnea, angina, and syncope. Dual chamber pacing has been proposed as a widely available alternative treatment for a subset of patients with symptomatic hypertrophic obstructive cardiomyopathy. Initial studies showed a reduction in gradient and an improvement in symptoms in almost 90% of patients with severe symptoms. We report the Mayo Clinic experience with dual chamber pacing in 38 patients with hypertrophic obstructive cardiomyopathy who had permanent pacemakers implanted for limiting symptoms intractable to medical therapy. After a mean +/- SD follow-up of 24 +/- 14 months, subjective improvement was reported in 47% of patients. However, there was no statistical difference between the maximal oxygen consumption at last follow-up and AAI pacing (atrial sensing and atrial pacing) (18.6 +/- 1.1 mL.kg-1.min-1) (i.e., when the pacemaker was implanted but not pacing continuously). This article discusses the clinical perspective on the utility of dual chamber pacing for patients with hypertrophic obstructive cardiomyopathy.

Pacing in hypertrophic cardiomyopathy

Dual chamber pacing has been proposed as an alternative to surgery in the management of hypertrophic cardiomyopathy. Reports have documented hemodynamic and symptomatic benefit from dual chamber pacing, raising the question of whether or not all patients with drug-refractory symptoms should undergo a trial of pacing before consideration of surgery. The enthusiasm for pacing in hypertrophic cardiomyopathy has generated a number of investigations addressing this issue, including several recently concluded clinical trials. This article reviews the recent experience with dual chamber pacing in hypertrophic cardiomyopathy.

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.

Percutaneous myocardial ablation in double-chamber right ventricle

Double-chamber right ventricle (DCRV) exhibits intracavitary outflow obstruction. We report the first case of percutaneous myocardial ablation of DCRV in a 73-year-old patient. An alcohol-induced conus branch occlusion provided the reduction of pressure gradient from 81 to 48 mm Hg and clinical improvement. This strategy may be an alternative therapy to surgery in the adult patients with DCRV. Cathet. Cardiovasc. Intervent. 49:97-101, 2000.

Electromechanical left ventricular behavior after nonsurgical septal reduction in patients with hypertrophic obstructive cardiomyopathy

OBJECTIVES

To investigate the electromechanical consequences of nonsurgical septal reduction in a group of patients with hypertrophic obstructive cardiomyopathy (HOCM).

BACKGROUND

Patients with HOCM may benefit symptomatically from nonsurgical septal reduction as an alternative to dual chamber pacing and sensing (DDD) pacing and surgical myectomy.

METHODS

We studied 20 symptomatic patients with HOCM (12 men), mean age 52 +/- 17 years, before and after septal reduction using echocardiography and electrocardiogram (ECG).

RESULTS

Septal reduction with a significant rise in cardiac enzymes was successfully achieved in all patients resulting in a 50% reduction in resting left ventricular (LV) outflow tract gradient within 24 h of procedure and an 80% reduction after six months. Left ventricular outflow tract diameter increased at 24 h with a further increase six months later. QRS duration increased by 35 ms at 24 h after procedure associated with right bundle branch block (RBBB) and significant rightward axis rotation in 16 patients. R-wave amplitude in V1 fell by 7 +/- 4 mm in 15/20 patients, 13 of whom developed reduction of septal long axis excursion. Left-axis deviation appeared in three patients and septal q-wave was suppressed in 12 long-axis excursion; peak shortening and lengthening rates all fell at the septal site by 20% at 24 h. Only septal excursion returned back to baseline values at six months. Wall motion also became incoordinate so that postejection septal shortening increased by three times control values at 24 h and by four times six months later.

CONCLUSIONS

Nonsurgical septal reduction is associated with a drop in LV outflow tract obstruction and the creation of a localized myocardial infarction (MI) increasing LV outflow tract diameter. The technique also results in a consistent alteration of septal activation and secondary incoordination. The latter could play a significant role in gradient reduction and symptomatic improvement in a manner similar to that seen with DDD pacing.

Changes in left ventricular filling and left atrial function six months after nonsurgical septal reduction therapy for hypertrophic obstructive cardiomyopathy

OBJECTIVES

The purpose of this study was to evaluate changes in left ventricular (LV) filling, left atrial (LA) volumes and function six months after nonsurgical septal reduction therapy (NSRT) for hypertrophic obstructive cardiomyopathy (HOCM).

BACKGROUND

Patients with HOCM frequently have enlarged left atria, which predisposes them to atrial fibrillation. Nonsurgical septal reduction therapy results in significant reduction in left ventricular outflow tract (LVOT) obstruction and symptomatic improvement. However, its effect on LV passive filling volume, LA volumes and function is not yet known.

METHODS

Thirty patients with HOCM underwent treadmill exercise testing as well as 2-dimensional and Doppler echocardiography before and six months after NSRT. Data included clinical status, exercise duration, LVOT gradient, mitral regurgitant (MR) volume, LV pre-A pressure and LA volumes. Left atrial ejection force and kinetic energy (KE) were computed noninvasively and were compared with 12 age-matched, normal subjects.

RESULTS

New York Heart Association (NYHA) class was lower and exercise duration was longer (p < 0.05) six months after NSRT. The LVOT gradient, MR volume and LV pre-A pressure were all significantly reduced. HOCM patients had larger atria, which had a higher ejection force and KE, compared with normal subjects (p < 0.01). After NSRT, LV passive filling volume increased (p < 0.01), whereas LA volumes, ejection force and KE decreased (p < 0.01). Reduction in LA maximal volume was positively related to changes in LV pre-A pressure (r = 0.8, p < 0.05) and MR volume (0.4, p < 0.05). Changes in LA ejection force were positively related to changes in LA pre-A volume (r = 0.7, p < 0.01) and KE (r = 0.81, p < 0.01). The increase in exercise duration paralleled the increase in LV passive filling volume (r = 0.85, p < 0.05).

CONCLUSIONS

Nonsurgical septal reduction therapy results in an increase in LV passive filling volume and a reduction in LA size, ejection force and KE.

Nonsurgical Treatment of Hypertrophic Cardiomyopathy

Nonsurgical septal reduction has been proposed as a means of treating patients with hypertrophic cardiomyopathy whose symptoms of exercise limitation by chest pain or breathlessness are inadequately controlled with standard medical therapy (i.e., beta blockers, calcium antagonists, or even DDD pacing).

Intraprocedural myocardial contrast echocardiography as a routine procedure in percutaneous transluminal septal myocardial ablation: detection of threatening myocardial necrosis distant from the septal target area

Percutaneous transluminal septal myocardial ablation (PTSMA) has been introduced as an alternative to surgery for symptomatic hypertrophic obstructive cardiomyopathy (HOCM). Visualization of the ablation area prior to induction of the chemical necrosis is possible by intraprocedural myocardial contrast echocardiography (MCE). We report on two patients in whom MCE showed opacification of the medial papillary muscle or the left ventricular posterolateral free wall. In both patients the correct ablation area could be identified by MCE after a change of the target vessel, thus avoiding potentially fatal complications due to induction of a necrosis of myocardium distant from the septal target area.

Pericardium-covered stent for septal myocardial ablation in hypertrophic obstructive cardiomyopathy

This report describes a patient with severe hypertrophic obstructive cardiomyopathy in New York Heart Association functional class III. Complete reduction of left ventricular outflow tract gradient was achieved by the selective occlusion of three target septal arteries with a pericardium-covered stent. The patient's in-hospital course was uneventful and has improved to functional class I.

Improvement in exercise capacity and exercise blood pressure response after transcoronary alcohol ablation therapy of septal hypertrophy in hypertrophic cardiomyopathy

Transcoronary alcohol ablation (TAA) therapy of septal hypertrophy was recently proposed as a therapeutic modality for obstructive hypertrophic cardiomyopathy (HC). However, questions remain about the effect of TAA on exercise performance. We performed a time-course analysis of exercise capacity and exercise hemodynamics in 20 patients with symptomatic obstructive HC after TAA. Symptom-limited bicycle exercise testing was performed before and 3 and 12 months after TAA, and cardiac catheterization at 3-month follow-up. The pressure gradient of the left ventricular outflow tract immediately decreased from 58 +/- 8 to 4 +/- 1 mm Hg at rest (p <0.01) and from 143 +/- 11 to 30 +/- 6 mm Hg after extrasystole (p <0.01), but partially recovered at 3-month follow-up (14 +/- 4 and 40 +/- 9 mm Hg, respectively). Left ventricular end-diastolic pressure was not changed after TAA. Peak oxygen consumption increased from 19 +/- 2 to 23 +/- 1 ml/kg/min (p < 0.01) and exercise duration from 573 +/- 47 to 742 +/- 46 seconds (p <0.01) at 3-month follow-up, but thereafter reached a plateau. Abnormal patterns of exercise blood pressure response were shown in 9 patients but normalized after TAA. Major complications occurred in 4 patients: no reflow to the left anterior descending coronary artery in 2 patients and ventricular tachycardia requiring cardioversion in 2 patients. During the follow-up period, all patients survived with symptomatic improvement in 17 patients. Thus, TAA is a promising therapeutic modality with improvement in exercise capacity and abnormal exercise blood pressure response in obstructive HC. However, potential serious complications should be considered in the application of TAA.

Electrocardiographic changes after alcohol septal ablation in hypertrophic obstructive cardiomyopathy

OBJECTIVE

To report acute and mid-term electrocardiographic changes in patients with hypertrophic obstructive cardiomyopathy (HOCM) after alcohol ablation of the first large septal branch of the left anterior descending coronary artery; and to relate electrocardiographic data with the left ventricular outflow tract pressure gradients.

PATIENTS

Nine consecutive symptomatic patients with HOCM (mean (SD) age 45 (12) years).

METHODS

Analysis of baseline and post-procedure ECGs and 24 hour ambulatory monitoring (up to six months). ECG data were related to left ventricular outflow tract pressure gradients.

RESULTS

One patient developed complete atrioventricular block requiring permanent pacing. The PR interval was significantly prolonged up to third month after ablation. Immediately after the procedure all patients developed right bundle branch block. At the sixth month of follow up, right bundle branch block was present in four patients. New anterior ST elevation developed immediately after ablation in five of the nine patients, and new Q waves in four. The QRS duration was significantly prolonged immediately after ablation and during follow up. There was significant but transient prolongation of QT-mean and QTc-mean intervals. QT dispersion, QTc dispersion, and JTc-mean interval were not affected. JT and JTc dispersions were transiently prolonged. No serious ventricular arrhythmias were recorded during Holter monitoring, either before or after the procedure. There were no significant correlations between the left ventricular outflow tract pressure gradient and QTc, QT-d, QTc-d, JTc, JT-d, JTc-d, or QRS duration before and after ablation.

CONCLUSIONS

Alcohol septal ablation for HOCM induces significant changes in the resting ECG in most patients, despite the occlusion of a relatively small artery. The changes include new Q waves, new bundle branch block, transient anterior ST segment elevation, atrioventricular block, and transient prolongation of QT interval.

Complete heart block and polymorphic ventricular tachycardia complicating myocardial infarction after occlusion of the first septal perforator with coronary stenting

We report a case of complete heart block (CHB) and polymorphic ventricular tachycardia (VT) which was associated with a modest-sized myocardial infarction (MI) following incidental occlusion of the first septal perforator (FSP) branch after stent deployment to the left anterior descending (LAD) coronary artery. These complications were successfully treated with temporary pacing and subsequently resolved with spontaneous recanalization of the first septal perforator. This case represents an interesting product of medical progress which defies the adverse natural history and poor prognosis of anteroseptal MI associated with CHB due to the small amount of myonecrosis associated with this event.

Transluminal percutaneous septal myocardial ablation in a patient with hypertrophic obstructive cardiomyopathy

Reduction of septal mass by inducing septal infarction using catheter techniques is a new therapy for hypertrophic obstructive cardiomyopathy (HOCM). We report a case of severe HOCM that was dramatically improved by this non-surgical treatment. A 60-year-old woman with HOCM had suffered dyspnea (NYHA class III) with syncopal attack despite medical treatment. Left heart catheterization showed a resting pressure gradient across the left ventricular outflow tract of 156 mmHg. Two proximal septal branches of the anterior descending coronary artery were catheterized with a balloon catheter by the usual percutaneous coronary angioplasty techniques and were completely blocked by injection of absolute alcohol. The pressure gradient decreased to 26 mmHg after the procedure. Symptoms were markedly improved (NYHA class I) without any medical treatment. The reduced pressure gradient was maintained at the 3-month follow-up catheterization (36 mmHg). Further long-term follow-up is needed, but this treatment would seem to to be a promising technique for reducing pressure gradient in symptomatic patients with HOCM.