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Hypertrophic cardiomyopathy (HCM) is an inherited cardiac disorder characterized by unexplained left ventricular hypertrophy in the absence of systemic or metabolic causes. Diagnosis relies on noninvasive imaging, including echocardiography, cardiac magnetic resonance imaging, or computed tomography, with defined wall thickness criteria supporting confirmation. Dynamic left ventricular outflow tract obstruction may occur and contribute to symptoms such as dyspnea, chest pain, and syncope. Management includes pharmacologic therapy and, in symptomatic patients with persistent obstruction, septal reduction therapy (SRT). Surgical myomectomy remains the standard in selected individuals, whereas alcohol septal ablation (ASA) offers a catheter-based alternative for appropriately selected patients. This continuing education activity reviews catheter-based management of HCM, emphasizing patient selection, procedural technique, and outcomes associated with ASA. Participants gain knowledge of indications for SRT, peri-procedural considerations, and expected hemodynamic and symptomatic improvements. Emerging approaches, including septal scoring along the midline endocardium, are introduced within the context of evolving minimally invasive strategies. Collaboration with an interprofessional heart team enhances patient outcomes through comprehensive risk assessment, individualized treatment planning, and coordinated periprocedural care, particularly in patients with advanced age, comorbidities, or elevated surgical risk. Objectives: Apply evidence-based guidelines to optimize diagnosis and management of hypertrophic cardiomyopathy with emphasis on left ventricular outflow tract obstruction and septal reduction therapy. Differentiate candidates appropriate for alcohol septal ablation from those better suited for surgical or medical management. Identify procedural risks and complications associated with alcohol septal ablation and implement best practices in catheter-based intervention for septal reduction. Implement interprofessional strategies to evaluate, identify, and coordinate the care of patients with hypertrophic cardiomyopathy undergoing catheter-based septal reduction by applying effective communication, assessing team roles, and improving collaborative decision-making across the healthcare team. Access free multiple choice questions on this topic.

Hypertrophic cardiomyopathy (HCM) is an inherited cardiac condition characterized by left ventricular muscular hypertrophy without other cardiac, systemic, or metabolic conditions like hypertension, aortic stenosis, amyloidosis, glycogen storage diseases, or lysosomal storage diseases. The diagnosis is established by noninvasive imaging modalities such as two-dimensional echocardiography, cardiovascular magnetic resonance, or cardiac computed tomography. HCM is diagnosed in adults by a maximal Left ventricular end-diastolic wall thickness of 1.5 cm or more or 1.3 cm to 1.4 cm in the presence of a positive family history or genetic test, provided other causes of hypertrophy are ruled out.[1][2] Septal reduction therapy (SRT), performed through percutaneous catheter-directed alcohol septal ablation (ASA) or via surgical myomectomy, is effective in reducing left ventricular outflow tract (LVOT) gradients.[3] LVOT gradient correlates with the degree of obstruction from hypertrophy. Patients with HCM with LVOT obstruction experience increased mortality, but evidence does not demonstrate improved survival using septal reduction therapy in those who are asymptomatic. SRT is indicated in symptomatic individuals who have maxed out on pharmacologic therapy within a comprehensive HCM center.[4] This topic focuses on the catheter management of HCM using ASA.

Complete heart block requiring a permanent pacemaker is the most common complication and can occur several days after the procedure. A myocardial infarction can occur during the procedure due to extravasation of the ethanol. Additional complications from imprecise ethanol placement include ventricular septal rupture, coronary dissection, tachyarrhythmia, and cardiac tamponade.[11] Additional complications secondary to cardiac catheterization included vascular access site hematoma, coronary artery dissection, thromboembolism, stroke, acute limb ischemia, right ventricular perforation from pacemaker insertion, and contrast injuries to the kidneys. Sedation can lead to respiratory failure, memory loss, and aspiration pneumonia.[14] The complication rate from alcohol septal ablation in centers of excellence is very low, and heart block is typically the only postprocedural event.

ASA performed by experienced interventional cardiologists in comprehensive HCM centers demonstrates excellent outcomes with minimal complications. Study results have shown that overall mortality from the procedures is less than 1%, and the survival rate is similar to that of surgical myomectomy.[9][16][17] Appropriate patient selection is the key to procedural success. Specialized nursing staff ensure appropriate pre- and postprocedural monitoring and minimize potentially life-threatening complications or the need for urgent intervention. An experienced surgeon is on standby to handle any potential procedure-related complications. A successful and safe alcohol septal ablation requires collaboration with qualified staff and a trained interdisciplinary team at every stage. Candidates for surgical or ablative intervention should be given full autonomy and introduced to all treatment options. The risks and benefits should be explained in detail. Referral to centers with comprehensive HCM care and excellent clinical outcomes should be standard. For severely symptomatic eligible individuals with LVOT obstruction due to HCM, SRT can be performed as an alternative to an escalation of medical therapy after shared decision-making and explaining the risks and benefits of all available treatment options.

The Interprofessional team is vital to the success of complex cardiac interventions. Patient hemodynamics are monitored preceding, during, and following the procedure. Correct catheter and sheath size, prepared in the correct order, appropriate balloons, contrast, and anticoagulation delivered by the support staff are crucial for procedural success. Unfractionated heparin is given to achieve the therapeutic activated clotting time of 250 to 300 seconds. Astute echocardiogram technicians should be available to monitor pericardial effusion and hemodynamics during the procedure. Vascular access sites are monitored for bleeding, and timely communication of any complications is paramount.

After the procedure, the patient is transferred to the cardiac intensive care unit for close telemetry monitoring, serial electrocardiograms, and cardiac enzymes to track the progression of the induced infarction for the first 48 hours. The transvenous pacemaker is left for 2 to 3 days. Patients are monitored for the following: Access site complications, such as groin or retroperitoneal hematoma Arrhythmias or heart blocks Hemodynamic instability Stroke/transient ischemic attack Contrast nephropathy Myocardial ischemia Following the initial 48 hours, the risk for an acute event is substantially decreased, and the stable patient can transfer to a telemetry floor. Persons most at risk for postprocedural heart block include older adults, those with preexisting conduction abnormalities, and women. TTE is done to assess LVOT gradient and mitral regurgitation before discharge. Patients follow up in the clinic where they are assessed for general well-being and any signs of access site complications like arteriovenous fistula, femoral artery pseudoaneurysm, hematoma, or infection. Patients undergo a repeat echocardiogram within 3 to 6 months to assess the LVOT gradient.[18]