Provocable Left Ventricular Outflow Tract Research Articles

Diagnosis and management of hypertrophic cardiomyopathy: European vs. American guidelines.

Hypertrophic cardiomyopathy (HCM) is the most common genetic heart disease, affecting 1:200 to 1:500 individuals worldwide. Guidelines on the diagnosis and management of HCM have been recently published by the European Society of Cardiology (ESC) and American societies. The ESC guidelines cover a broad range of cardiomyopathies, including HCM, with 119 recommendations, whereas the American guidelines focus exclusively on HCM with 141 specific recommendations. Both guidelines emphasize a comprehensive diagnostic approach, including imaging and genetic testing, but differ in some specific aspects. For example, sudden cardiac death (SCD) risk assessment is a primary point of divergence. The ESC guidelines advocate for the use of a validated Risk-SCD calculator, while the American guidelines rely on specific risk markers for individualized risk evaluation. Management strategies also vary: both guidelines prioritize beta-blockers and calcium channel blockers in patients with resting or provocable left ventricular outflow tract (LVOT) obstruction. If beta-blockers (or verapamil/diltiazem) are ineffective, either disopyramide or the myosin inhibitor mavacamten may be an option with slightly different indications among the two guidelines. Septal reduction therapy is recommended in ESC guidelines for symptomatic patients with significant LVOT gradients, while American guidelines suggest earlier myectomy for certain clinical factors and emphasize shared decision-making. The ESC guidelines recommend sequential atrioventricular pacing and dual-chamber defibrillators for reducing LVOT gradients. The American guidelines focus on genetic testing for risk assessment and suggest periodic cardiac magnetic resonance imaging. This paper provides a detailed comparison of these guidelines, highlighting key differences and areas needing further research and expert debate.

Radiofrequency septal reduction in symptomatic hypertrophic obstructive cardiomyopathy

Alcohol septal ablation remains the only approved nonsurgical therapeutic alternative for patients with drug-resistant hypertrophic obstructive cardiomyopathy (HOCM). Radiofrequency (RF) ablation offers another option for treating HOCM. The purpose of this study was to determine whether irrigated RF ablation can reduce symptomatic outflow tract obstruction in adults with HOCM. Patients with symptomatic HOCM and an outflow gradient of >50 mm Hg despite medication were offered RF ablation. In 11 patients, the hypertrophied interventricular septum was localized on a 3-dimensional mapping system and ablated via a transmitral or retrograde aortic approach. Ten of 11(91%) patients had a significant and persistent reduction in resting and provocable left ventricular outflow tract gradients. Mean resting gradients at 12 months postprocedure were reduced by 85% (66.7 mm Hg at baseline to 10.0 mm Hg at 12 months); mean provocable gradients were reduced by 85% from baseline (136.2 mm Hg at baseline to 20.0 mm Hg at 12 months). Functional New York Heart Association heart classification improved from class 3.0 ± 0.0 in all patients to class mean of 1.8 ± 0.8. RF septal ablation for the treatment of HOCM is a safe therapeutic option that allows for significant reduction in left ventricular outflow tract gradients, improvement in symptoms, and increase in efficacy rates comparable to reported rates for alcohol septal ablation.

The Natural History of Nonobstructive Hypertrophic Cardiomyopathy

ObjectiveTo describe the survival of a large nonobstructive hypertrophic cardiomyopathy (NO-HCM) cohort and to identify risk factors for increased mortality in this population. Patients and MethodsPatients were identified from the Mayo Clinic HCM database from January 1, 1975, through November 30, 2006, for this retrospective observational study. Patients with resting or provocable left ventricular outflow tract gradients were excluded. Echocardiographic, clinical, and genetic data were compared between subgroups, and survival data were compared with expected population rates. ResultsA total of 706 patients with NO-HCM were identified. During median follow-up of 5 years (mean, 7 years), there were 208 deaths. Overall survival was no different than expected compared with age- and sex-matched white US population mortality rates (P=.77). Independent predictors of death were age at diagnosis, “burned out” HCM, and history of transient ischemic attack or stroke; use of an implantable cardioverter defibrillator (ICD) was inversely related to death. After exclusion of patients with an ICD, there was no difference in survival compared with age- and sex- matched individuals (P=.39); age, previous transient ischemic attack/stroke, and burned out HCM were predictors of death. ConclusionIn this cohort, patients with NO-HCM had similar survival rates as age- and sex-matched white US population mortality rates. Although use of an ICD was inversely related to death, no differences in overall survival were seen after those patients were excluded. Burned out HCM was independently associated with an increased risk of death, identifying a subset of patients who may benefit from more aggressive therapies.

TCT-747 Utility of isoproterenol challenge in predicting symptomatic response to myectomy in hypertrophic cardiomyopathy with occult obstruction

Septal myectomy is the gold standard for medically-refractory patients with hypertrophic obstructive cardiomyopathy (HCM). There is a subset of patients who have severe exertional symptoms without a resting or provocable left ventricular outflow tract (LVOT) gradient on noninvasive testing. These

TCTAP A-073 Alcohol Septal Ablation in Hypertrophic Cardiomyopathy: A Prospective Study

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease caused by multiple mutations of cardiac sarcomeres. Resting and provocable left ventricular outflow tract (LVOT) gradient is a strong determinant of morbidity and mortality in patients with hypertrophic

The influence of aortoseptal angulation on provocable left ventricular outflow tract obstruction in hypertrophic cardiomyopathy

ObjectivesAortoseptal angulation (AoSA) can predict provocable left ventricular outflow tract obstruction (LVOTO) in patients with symptomatic hypertrophic cardiomyopathy (HCM). Lack of a standardised measurement technique in HCM without the need...

Exercise in Hypertrophic Cardiomyopathy

The risk of sudden cardiac death (SCD) associated with vigorous athletic competition in individuals with hypertrophic cardiomyopathy (HCM) is well documented, and is the basis for recommended exclusion from competitive sports independent of other risk factors. Although SCD risk with recreational exercise is less well defined, published guidelines for participation in recreational sports, based on a consensus of expert opinion, offer a valuable framework for counseling patients. Exercise stress testing is an important diagnostic and prognostic tool in the evaluation of HCM patients, providing an objective measure of functional capacity, physiologic hemodynamic responses to stress, presence of ischemia, and provocable left ventricular outflow tract obstruction. The value of cardiopulmonary exercise testing in HCM is less well studied than in the heart failure population, but can be used to set a safe target for exercise intensity as part of an individualized exercise prescription. The long-term effects of exercise on HCM pathophysiology are largely theoretical at this stage. Potential harmful effects of fatiguing exercise include prolonged contractile dysfunction resulting from microvascular ischemia and energetic compromise. Conversely, several animal studies have shown that voluntary exercise prevents or reverses many pathologic features of HCM, including those related to apoptosis and energetics. Substantial evidence for health-promoting benefits of exercise in the general population, in addition to promising safety and efficacy data in patients with chronic heart failure, emphasizes the need to attain a reasonable balance between potential risks and benefits of aerobic fitness in individuals with HCM.

Long-term results of left ventricular myotomy and myectomy for obstructive hypertrophic cardiomyopathy

A retrospective analysis of patients with hypertrophic obstructive cardiomyopathy treated by left ventricular myotomy and myectomy from 1972 to 1994 is reported. There were 158 patients (81 male and 77 female) with a mean age of 50.2 (±17.2) years (range 12 to 80 years). One hundred nine patients (69%) were 60 years of age or younger, and 49 patients (31%) were older than 60 years. The overall mean follow-up period was 6.1 (±4.8) years (range 0.1 to 19.3 years) and was 94% complete with a cumulative total of 956 patient-years. Preoperative exertional dyspnea was present in 84%, chest pain in 70%, presyncope in 54%, syncope in 31%, and cardiac arrest in 5% of patients. Preoperative cardiac catheterization was done in 150 patients, with mitral regurgitation detected in 104 patients (67%). The average maximal provocable left ventricular outflow tract gradient was 118 (±46) mm Hg (range 25 to 250 mm Hg). The average preoperative echocardiographic gradient at rest was 64 mm Hg, 20 mm Hg in the early postoperative period and 10 mm Hg in the late postoperative period. The mean septal thickness was 2.2 (±0.6) cm, 1.9 (±0.7) cm in the early postoperative period ( p < 0.05 vs preoperative) and 1.7 (±0.5) cm in the late postoperative period (p < 0.05 vs preoperative). The overall 30-day operative mortality rate was 3.2% (5/158), and 0% for 109 patients 60 years of age or younger. Causes of death included myocardial infarction and left ventricular free wall rupture, myocardial failure from septal perforation, sepsis, cerebrovascular accident caused by thromboembolism, and delayed cardiac tamponade in one patient each. Concomitant coronary artery bypass grafting was performed in 22 patients (19.3% of patients ≥40 years of age) and mitral valve replacement in 5 patients (3.2%). One hundred nine patients (69%) are alive, 10 patients (6.3%) were lost to follow-up, and 39 patients died (24.7%, including operative deaths). Actuarial survivals at 1, 5, 10, and 15 years were 92.4% ±2.2%, 85.4% ±3.1%, 71.5% ±4.6%, and 46% ±9%, respectively. The overall linearized death rate for discharged patients was 1.9%/pt-yr, and for cardiac related deaths it was 1.7%/pt-yr. Thirty-nine (36%) of the 109 survivors received β-adrenergic blockers, and 30 (28%) received calcium channel blockers. Ninety-four patients had improvement in New York Heart Association functional class, 10 had improvement in symptoms but not in functional class, and 5 had no improvement in functional class or symptoms. Neither preoperative hemodynamic values nor routine echocardiographic measurements significantly correlated with quality of postoperative results. Left ventricular myotomy and myectomy is a safe and reproducibly effective operative treatment for medically refractory hypertrophic obstructive cardiomyopathy, especially for patients 60 years of age or younger. Improvement in functional class and symptoms can be expected in nearly all patients. The results of myotomy and myectomy serve as a standard for comparison with other interventions for medically refractory cardiomyopathy. (J T HORAC C ARDIOVASC S URG 1996;111:586-94)

The results of operation in patients with hypertrophic cardiomyopathy and pulmonary hypertension

The clinical course and hemodynamic results in patients undergoing operation for obstructive hypertrophic cardiomyopathy with preoperative pulmonary arterial hypertension were unknown. The hypothesis tested in this retrospective study was that operative relief of left ventricular outflow tract obstruction resulted in a substantial reduction in pulmonary artery pressures and mitral regurgitation without necessitating mitral valve replacement. Patients were included if their preoperative pulmonary systolic pressure was greater than 35 mm Hg and if they were without concomitant cardiac disease, with the exception of mitral regurgitation. Since 1962, 49 patients who fit our criteria underwent left ventricular myotomy and myectomy with 98% follow-up. Mean follow-up was 7.9 +/- 0.7 (mean +/- standard error of the mean) years with a range of 0.8 to 18.4 years. Early hospital mortality rate was 12% (n = 6); two deaths from low cardiac output and four from arrhythmia. There were 43 (88%) hospital survivors and 18 late deaths. Actuarial survival rate after operation was 87% +/- 5% (n = 31) at 5 years and 55% +/- 8% (n = 9) at 10 years. Thirty-nine of 43 survivors (91%) returned 9 +/- 1 months postoperatively for follow-up evaluation including cardiac catheterization. The majority (83%) were in New York Heart Association functional class I or II postoperatively. Cardiac catheterizations indicated a fall in pulmonary arterial systolic pressure from 62 +/- 3 (range = 36 to 105) to 38 +/- 2 (range = 21 to 65) mm Hg (p = 0.0001) with no difference in right atrial pressure or cardiac output. Pulmonary arterial wedge mean pressure decreased from 24 +/- 1 to 16 +/- 5 mm Hg (p = 0.0002) and preoperative mitral regurgitation improved or was abolished in 85% of patients studied (n = 13). Rest and maximal provocable left ventricular outflow tract gradients decreased from 81 +/- 7 and 103 +/- 5 to 14 +/- 3 and 45 +/- 8 mm Hg, respectively (p = 0.0001). Comparison of the above-mentioned patients, operated on since 1982, with a preoperatively matched group who underwent mitral valve replacement in the same interval showed no statistically significant difference in mortality, morbidity, hemodynamic outcome, or functional outcome with a mean follow-up of 2 years. We conclude that a consistent, significant reduction (mean = 40%) in preoperative pulmonary arterial systolic pressure, clinical symptoms, and mitral regurgitation occurs with relief of outflow tract obstruction by left ventricular myotomy and myectomy and that pulmonary hypertension and mitral regurgitation are not indications for mitral valve replacement in these patients.

Systolic anterior motion of the mitral valve in the absence of asymmetric septal hypertrophy.

Asymmetric septal hypertrophy (ASH) is considered the unifying link in the spectrum of hypertrophic cardiomyopathies. ASH and mitral valve systolic anterior motion (SAM) are the two most important echocardiographic criteria for the diagnosis of idiopathic hypertrophic subaortic stenosis (IHSS). Ten patients found have SAM without ASH were studied. Septal thickness, thickening, and excursion were normal. Seven patients had left ventricular ejection times (LVET) measured before and after amyl nitrite inhalation. In six of them, corrected LVET increased by more than 40 msec. Four patients underwent diagnostic cardiac catheterization. Resting or provocable left ventricular outflow tract (LVOT) gradients were demonstrable in all four patients. The echocardiographic features in patients with SAM alone, ASH and SAM, and ASH alone were compared. compared. LVOT measurements in patients with SAM alone (2.2 +/- .4 cm) and ASH and SAM (2.1 +/- .5 cm) were similar and narrower than in patients with ASH alone (2.8 +/- .5 cm, P less than 0.001). Ejection fractions in patients with SAM alone (79 +/- 10%) were greater than in patients with ASH and SAM (66 +/- 16%, P less than 0.02) or ASH alone (60 +/- 15%, P less than 0.001). Thus, dynamic left ventricular outflow obstruction can exist in the absence of echocardiographic ASH. LVOT width and abnormal LV ejection dynamics may contribute to the LVOT obstruction with or without the presence of ASH.