Transitioning disopyramide to mavacamten in obstructive hypertrophic cardiomyopathy: A case series and clinical guide.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is a genetic disorder for which first-line treatments for obstructive HCM (oHCM) include beta-blockers, non-dihydropyridine calcium channel blockers, and disopyramide for refractory cases. Mavacamten, a selective cardiac myosin inhibitor, is indicated for symptomatic oHCM to improve functional capacity and symptoms. Use of disopyramide and mavacamten together is not recommended due to concerns of additive negative inotropic effects. Transitioning from disopyramide to mavacamten may be preferred to avoid adverse effects and frequent administration, however, the best approach for making the transition has not been established. CASES: We present a series of seven patients with oHCM who transitioned from disopyramide to mavacamten and underwent echocardiograms mandated by a Risk Evaluation and Mitigations Strategies program. Two methods were employed. The first approach, involving washout of disopyramide before starting mavacamten, resulted in worsening of heart failure symptoms in the first two cases. The second approach, involving tapering disopyramide when starting mavacamten, was successfully implemented in the last five cases, with no adverse effects or worsening of systolic dysfunction. CONCLUSION: Our method of tapering disopyramide when starting mavacamten using a stepwise approach is feasible and safe. Our report fulfills an unmet need by serving as a guide for other clinicians who seek to transition their patients from disopyramide to mavacamten.

Disopyramide is a safe and effective treatment for children with obstructive hypertrophic cardiomyopathy.

BACKGROUND: Left ventricular outflow tract obstruction (LVOTO) is present in 1/3 of children with Hypertrophic Cardiomyopathy (HCM). Disopyramide improves symptoms associated with LVOTO and delays surgical intervention in adults, but it is not licensed in children. AIM: To describe a single-centre thirty-year experience of using disopyramide to treat LVOTO-related symptoms in a paediatric HCM cohort. METHODS: Clinical data were collected for all patients meeting diagnostic criteria for HCM (<18 years) at the time of initiation, 6 months after, and last follow-up or end of disopyramide treatment. It included demographics, clinical history, 12­lead electrocardiography, and echocardiography. Comparisons between baseline and 6 month follow up, and end of follow up respectively were performed. RESULTS: Fifty-one patients with HCM were started on disopyramide at a mean age 10.2±5.3 years. At 6 months, of those previously symptomatic, 33(86.8%) reported an improvement of symptoms and 12(31.6%) were asymptomatic. PR interval, corrected QT interval and maximal LVOT gradient had not significantly changed, but fewer participants were noted to have systolic anterior motion of the mitral valve 31 (72.1%) vs. 26 (57.80%). Patients were followed up for a median of 1.9 years (IQR 0.83-4.5). Nine patients (17.6%) reported side effects, and eleven patients (33.3%) with initial improvement in symptoms reported a return or worsening of symptoms requiring a change in medication (n = 4, 12.1%) or left ventricular septal myomectomy (n = 7, 21.2%) during follow up. CONCLUSION: Disopyramide is a safe and effective treatment for LVOTO-related symptoms in childhood obstructive HCM. Any delay in the need for invasive intervention, particularly during childhood, is of clear clinical benefit.

Bisoprolol for treatment of symptomatic patients with obstructive hypertrophic cardiomyopathy. The BASIC (bisoprolol AS therapy in hypertrophic cardiomyopathy) study.

AIMS: To evaluate the role of bisoprolol to control symptoms and left ventricular outflow tract obstruction (LVOTO) in a consecutive cohort of adults with hypertrophic cardiomyopathy (HCM). METHODS AND RESULTS: In this retrospective study, patients with HCM with an LVOT gradient ≥50 mmHg after Valsalva manoeuvre and New York Heart Association (NYHA) class II-III symptoms were assigned to receive bisoprolol (starting at 1.25 mg daily). The initial dose was increased every two weeks to achieve the target in LVOT gradient <30 mmHg or the maximum tolerated dose. The primary endpoint was the achievement of a LVOT gradient <30 mmHg and ≥ 1 NYHA class improvement. The secondary endpoints were proportion of patients with LVOT gradient <30 mmHg or < 50 mmHg, proportion of patients with ≥1 NYHA class improvement, and change from baseline in LVOT gradient. Between December 2001 and December 2020, 92 patients were enrolled into the study. Sixteen (17%) patients on bisoprolol met the primary endpoint. Bisoprolol reduced the LVOT gradient to less than 30 mmHg in 33 (36%) patients, to less than 50 mmHg in 57 (62%), and improved NYHA class in 30 (33%). The mean reduction of LVOT gradient on bisoprolol was 28 (±14) mmHg and the percentage reduction was 42 (±21) %. In 35 (38%) patients, bisoprolol did not reduce the gradient to less than 50 mmHg requiring disopyramide and/or myectomy to achieve this goal. CONCLUSION: Treatment with bisoprolol was well-tolerated and effective in relieving obstruction and improving symptoms in a significant proportion of patients with symptomatic obstructive HCM.

Prediction and Prevention of Sudden Death in Young Patients (<20 years) With Hypertrophic Cardiomyopathy.

Highly reliable identification of adults with hypertrophic cardiomyopathy (HC) at risk for sudden death (SD) has been reported. A significant controversy remains, however, regarding the most reliable risk stratification methodology for children and adolescents with HC. The present study assesses the accuracy of SD prediction and prevention with prophylactic implantable cardioverter-defibrillators (ICDs) in young HC patients. The study group is comprised of 146 HC patients <20 years of age evaluated consecutively over 17 years with prospective risk stratification and ICD decision-making. We relied on ≥1 established individual risk markers considered major within each patient's clinical profile, based on an enhanced American College of Cardiology /American Heart Association (ACC/AHA) guidelines algorithm. Of the 60 largely asymptomatic patients implanted with primary prevention ICDs at age 15 ± 4 years, 9 (15%) experienced device therapy terminating potentially lethal ventricular tachyarrhythmias and restoring sinus rhythm at 19 ± 6 years (range 9 to 29), 5.1 ± 6.0 years after implant; 3 patients had multiple appropriate ICD discharges. The individual risk marker algorithm was associated with 100% sensitivity in predicting SD events (95%CI: 69, 100) and 63% specificity for identifying patients without events (95%CI: 54, 71). Of these patients with device therapy, massive left ventricular hypertrophy (absolute wall thickness ≥30 mm) was the most common predictor, present in 70% of patients either alone or in combination with other risk markers. Each of the 146 study patients have survived to date at 22 ± 5 years, including all 86 without ICD recommendations. In conclusion, an enhanced ACC/AHA risk stratification strategy, based on established individual risk markers, was highly reliable in prospectively predicting SD events in children and adolescents with HC, and preventing arrhythmia-based catastrophes in this susceptible high risk population.

Left ventricular outflow tract pressure gradient changes after carvedilol-disopyramide cotherapy in a cat with hypertrophic obstructive cardiomyopathy.

Disopyramide reduces the left ventricular outflow tract (LVOT) pressure gradient and improves symptoms in humans with hypertrophic obstructive cardiomyopathy (HOCM). However, the efficacy of disopyramide in cats has not been reported. We treated a cat with HOCM with carvedilol and disopyramide cotherapy and monitored the changes in LVOT flow velocity and N-terminal pro B-type natriuretic peptide (NT-proBNP) concentration. A 10-month-old neutered male Norwegian Forest cat was referred with a moderate systolic cardiac murmur. Echocardiography revealed thickening of the left ventricular wall, systolic anterior motion of the mitral valve leaflets, and turbulent aortic flow in the LVOT at systole. The LVOT flow velocity was 5.6 m/s. The plasma NT-proBNP concentration exceeded 1,500 pmol/L. The cat was diagnosed with HOCM and the ß-blocker carvedilol was started and gradually increased to 0.30 mg/kg, bid. After 57 days, the LVOT flow velocity (4.8 m/s) and plasma NT-proBNP concentration (870 pmol/L) had decreased but remained elevated. Therefore, disopyramide was added at 5.4 mg/kg po bid and increased to 10.9 mg/kg po bid after 22 days. After 141 days of carvedilol and disopyramide treatment, the systolic anterior motion of the mitral valve leaflets had disappeared and the LVOT flow velocity and plasma NT-proBNP concentration had decreased to 0.7 m/s and 499 pmol/L, respectively. No adverse effect has been observed during the follow-up. Disopyramide might relieve feline LVOT obstruction after only partial response to a beta-blocker. Further large-scale studies are required to investigate the efficacy and safety of disopyramide use in cats with moderate to severe HOCM.

Structure-activity relationship and cardiac safety of 2-aryl-2-(pyridin-2-yl)acetamides as a new class of broad-spectrum anticonvulsants derived from Disopyramide.

A series of 2-aryl-2-(pyridin-2-yl)acetamides were synthesized and screened for their anticonvulsant activity in animal models of epilepsy. The compounds were broadly active in the 'classical' maximal electroshock seizure (MES) and subcutaneous Metrazol (scMET) tests as well as in the 6 Hz and kindling models of pharmacoresistant seizures. Furthermore, the compounds showed good therapeutic indices between anticonvulsant activity and motor impairment. Structure-activity relationship (SAR) trends clearly showed the highest activity resides in unsubstituted phenyl derivatives or compounds having ortho- and meta- substituents on the phenyl ring. The 2-aryl-2-(pyridin-2-yl)acetamides were derived by redesign of the cardiotoxic sodium channel blocker Disopyramide (DISO). Our results show that the compounds preserve the capability of the parent compound to inhibit voltage gated sodium currents in patch-clamp experiments; however, in contrast to DISO, a representative compound from the series 1 displays high levels of cardiac safety in a panel of in vitro and in vivo experiments.

Markers of responsiveness to disopyramide in patients with hypertrophic cardiomyopathy.

BACKGROUND: Significant left-ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM) may result in symptoms and is associated with adverse outcomes. Although disopyramide can reduce resting gradients, nearly 30% of HCM patients do not respond. We sought to study the clinical and echocardiographic variables associated with disopyramide-induced LVOT-gradient reduction. METHODS: Forty-one disopyramide-treated HCM patients (average daily-dose 305 mg) were subdivided into two groups: (1) nineteen responders, with a reduction of LVOT-gradients of at least 30% from baseline, and (2) twenty-two non-responders, in whom LVOT-gradients did not change or increased following treatment. All patients had a thorough clinical and echocardiographic assessment pre- and post-treatment initiation. RESULTS: Patients who responded to disopyramide had better pretreatment left ventricular (LV) systolic function (LV ejection fraction of 67.9 ±â€¯5.6% vs. 59.7 ±â€¯5.8%, p = 0.0001), better LV global longitudinal strain (-17.9 ±â€¯2.3% vs. -16.1 ±â€¯2.5%, p = 0.048), less mitral regurgitation, smaller LV size (indexed LV end-systolic volume of 16.2 ±â€¯5.1 ml/m2 vs. 23.2 ±â€¯6.8 ml/m2, p = 0.001), and lower LV maximal wall thickness (17.2±3 mm vs.19.2 ±â€¯3.4 mm, p = 0.046). Baseline left atrial (LA) volumes were significantly lower in the responders, with higher indices of LA ejection fraction (62 ±â€¯11.2% vs. 50.5 ±â€¯12.2%, p = 0.005), systolic LA strain (34 ±â€¯12.4% vs. 25.8 ±â€¯10.6%, p = 0.04), and LA strain-rate (1.34 ±â€¯0.49%/sec vs. 0.99 ±â€¯0.24%/sec, p = 0.012). In multivariable analysis, the presence of reduced LV systolic function and systolic LA strain-rate remained independently associated with poor response to disopyramide. CONCLUSIONS: Obstructive HCM patients with more severe disease at baseline tend to respond less to disopyramide treatment. In those patients, early referral for alcohol septal ablation or myectomy surgery should be considered.

Lifestyle Modification and Medical Management of Hypertrophic Cardiomyopathy.

Hypertrophic cardiomyopathy is a heterogenous condition associated with a myriad of symptoms. Just as in other disease states, the aim of medical therapy is the alleviation of suffering, improvement of longevity, and the prevention of complications. This article focuses on the associated comorbidities seen in patients with hypertrophic cardiomyopathy, potential lifestyle interventions, and conventional medical treatments for symptomatic hypertrophic cardiomyopathy.

Theophylline as an adjunct to control malignant ventricular arrhythmia associated with early repolarization.

Early repolarization (ER) has been associated with an increased risk of sudden cardiac arrest. Interestingly, ventricular arrhythmias seem to be triggered by parasympathetic stimulation. In the present case report, we describe complete control of highly frequent malignant ventricular arrhythmias after adding theophylline to ineffective oral hydroquinidine and high-rate pacing in a patient suffering from malignant ER. We hypothesize that the theophylline-mediated enhanced beta-adrenergic stimulation could reduce the transmural myocardial voltage discrepancy by increasing the inward ICa,L current.

Modelling the effects of quinidine, disopyramide, and E-4031 on short QT syndrome variant 3 in the human ventricles.

OBJECTIVE: Short QT syndrome (SQTS) is an inherited cardiac channelopathy, but at present little information is available on its pharmacological treatment. SQT3 variant (linked to the inward rectifier potassium current I K1) of SQTS, results from a gain-of-function mutation (Kir2.1 D172N) in the KCNJ2-encoded channels, which is associated with ventricular fibrillation (VF). Using biophysically-detailed human ventricular computer models, this study investigated the potential effects of quinidine, disopyramide, and E-4031 on SQT3. APPROACH: The ten Tusscher et al model of human ventricular myocyte action potential (AP) was modified to recapitulate the changes in I K1 due to heterozygous and homozygous forms of the D172N mutation. Wild-type (WT) and mutant WT-D172N and D172N formulations were incorporated into one-dimensional (1D) and 2D tissue models with transmural heterogeneities. Effects of drugs on channel-blocking activity were modelled using half-maximal inhibitory concentration (IC50) and Hill coefficient (nH) values. Effects of drugs on AP duration (APD), effective refractory period (ERP) and QT interval of pseudo-ECGs were quantified, and both temporal and spatial vulnerability to re-entry was measured. Re-entry was simulated in the 2D ventricular tissue. MAIN RESULTS: At the single cell level, the drugs quinidine, disopyramide, and E-4031 prolonged APD at 90% repolarization (APD90), and decreased maximal transmural voltage heterogeneity (δV); this caused the decreased transmural dispersion of APD90. Quinidine prolonged the QT interval and decreased the T-wave amplitude. Furthermore, quinidine increased ERP and reduced temporal vulnerability and increased spatial vulnerability, resulting in a reduced susceptibility to arrhythmogenesis in SQT3. In the 2D tissue, quinidine was effective in terminating and preventing re-entry associated with the heterozygous D172N condition. Quinidine exhibited significantly better therapeutic effects on SQT3 than disopyramide and E-4031. SIGNIFICANCE: This study substantiates a causal link between quinidine and QT interval prolongation in SQT3 Kir2.1 mutations and highlights possible pharmacological agent quinidine for treating SQT3 patients.

In silico assessment of the effects of quinidine, disopyramide and E-4031 on short QT syndrome variant 1 in the human ventricles.

AIMS: Short QT syndrome (SQTS) is an inherited disorder associated with abnormally abbreviated QT intervals and an increased incidence of atrial and ventricular arrhythmias. SQT1 variant (linked to the rapid delayed rectifier potassium channel current, IKr) of SQTS, results from an inactivation-attenuated, gain-of-function mutation (N588K) in the KCNH2-encoded potassium channels. Pro-arrhythmogenic effects of SQT1 have been well characterized, but less is known about the possible pharmacological antiarrhythmic treatment of SQT1. Therefore, this study aimed to assess the potential effects of E-4031, disopyramide and quinidine on SQT1 using a mathematical model of human ventricular electrophysiology. METHODS: The ten Tusscher et al. biophysically detailed model of the human ventricular action potential (AP) was modified to incorporate IKr Markov chain (MC) formulations based on experimental data of the kinetics of the N588K mutation of the KCNH2-encoded subunit of the IKr channels. The modified ventricular cell model was then integrated into one-dimensional (1D) strand, 2D regular and realistic tissues with transmural heterogeneities. The channel-blocking effect of the drugs on ion currents in healthy and SQT1 cells was modeled using half-maximal inhibitory concentration (IC50) and Hill coefficient (nH) values from literatures. Effects of drugs on cell AP duration (APD), effective refractory period (ERP) and pseudo-ECG traces were calculated. Effects of drugs on the ventricular temporal and spatial vulnerability to re-entrant excitation waves were measured. Re-entry was simulated in both 2D regular and realistic ventricular tissue. RESULTS: At the single cell level, the drugs E-4031 and disopyramide had hardly noticeable effects on the ventricular cell APD at 90% repolarization (APD90), whereas quinidine caused a significant prolongation of APD90. Quinidine prolonged and decreased the maximal transmural AP heterogeneity (δV); this led to the decreased transmural heterogeneity of APD across the 1D strand. Quinidine caused QT prolongation and a decrease in the T-wave amplitude, and increased ERP and decreased temporal susceptibility of the tissue to the initiation of re-entry and increased the minimum substrate size necessary to prevent re-entry in the 2D regular model, and further terminated re-entrant waves in the 2D realistic model. Quinidine exhibited significantly better therapeutic effects on SQT1 than E-4031 and disopyramide. CONCLUSIONS: The simulated pharmacological actions of quinidine exhibited antiarrhythmic effects on SQT1. This study substantiates a causal link between quinidine and QT interval prolongation in SQT1 and suggests that quinidine may be a potential pharmacological agent for treating SQT1 patients.

Medical Management (ß Blocker ± Disopyramide) of Left Ventricular Outflow Gradient Secondary to Systolic Anterior Motion of the Mitral Valve After Repair.

Systolic anterior motion of the mitral valve (SAM) occurs intraoperatively after mitral valve repair (MVRr) in up to 14% of cases and typically resolves in the operating room with conservative measures. Less commonly SAM may also occur in the early or late postoperative period. The clinical course and optimal management of such cases is poorly defined, but reoperation is common. We describe our experience using disopyramide to successfully treat postoperative SAM refractory to beta blockade. Seven patients were retrospectively identified with mitral valve prolapse who underwent MVRr from 2003 to 2015 and were found during follow-up to have severe SAM with a left ventricular outflow tract (LVOT) gradient not observed intraoperatively. All 7 patients were successfully managed medically. In 5 cases, SAM persisted even after maximization of beta blockade, and the addition of disopyramide led to significant improvement or resolution of SAM, the LVOT gradient, and mitral regurgitation. The postoperative LVOT gradient initially exceeded 30 mm Hg in 6 of 7 patients. In 2 patients, the LVOT gradient exceeded 100 mm Hg, and both were managed medically with disopyramide with complete resolution of SAM. In conclusion, SAM after MVRr typically follows a benign clinical course and can be managed medically in most cases. When an initial treatment strategy of beta blockade is insufficient, the addition of disopyramide can effectively alleviate and terminate this condition and should be considered before reoperation.

Drug Therapy for Hypertrophic Cardiomypathy: Physiology and Practice.

HCM is the most common inherited heart condition occurring in 1:500 individuals in the general population. Left ventricular outflow obstruction at rest or after provocation occurs in 2/3 of HCM patients and is a frequent cause of limiting symptoms. Pharmacologic therapy is the first-line treatment for obstruction, and should be aggressively pursued before application of invasive therapy. Beta-blockade is given first, and up-titrated to decrease resting heart rate to between 50 and 60 beats per minute. However, beta-blockade is not expected to decrease resting gradients; its effect rests on decreasing the rise in gradient that accompanies exercise. For patients who fail beta-blockade the addition of oral disopyramide in adequate dose often will decrease resting gradients and offer meaningful relief of symptoms. Disopyramide vagolytic side effects, if they occur, can be greatly mitigated by simultaneous administration of oral pyridostigmine. This combination allows adequate dosing of disopyramide to achieve therapeutic goals. Verapamil utility in obstructive HCM with high resting gradients is limited by its vasodilating effects that can, infrequently, worsen gradient and symptoms. As such, we tend to avoid it in patients with high gradients and limiting heart failure symptoms. In a head-to-head comparison of intravenous drug administration in individual obstructive HCM patients the relative efficacy for lowering gradient was disopyramide > beta-blockade > verapamil. Severe symptoms in non-obstructive HCM are caused by fibrosis or severe myocyte disarray, and often by very small LV chamber size. Severe symptoms caused by these anatomic and histologic abnormalities, in the absence of obstruction, are less amenable to current pharmacotherapy. New pharmacotherapeutic approaches to HCM are on the horizon, that are to be evaluated in formal therapeutic trials.

Characterization of Disopyramide derivative ADD424042 as a non-cardiotoxic neuronal sodium channel blocker with broad-spectrum anticonvulsant activity in rodent seizure models.

It was reported that antiarrhythmic drugs (AADs) can be useful in controlling refractory seizures in humans or in enhancing the action of antiepileptic drugs (AEDs) in animal models. Disopyramide phosphate (DISO) is an AAD that blocks sodium channels in cardiac myocytes. We evaluated a DISO derivative, 2-(2-chlorophenyl)-2-(pyridin-2-yl)acetamide (ADD424042) for its anticonvulsant activity in a battery of rodent models of epileptic seizures. The compound displayed a broad spectrum of activity in the 'classical' models as well as in the models of pharmacoresistant seizures. Furthermore, ADD424042 showed good therapeutic indices between the anticonvulsant activity and the motor impairment. On the contrary, no anticonvulsant effects but severe lethality were observed in the primary anticonvulsant testing of the parent DISO. By performing the whole-cell voltage-clamp experiments in dispersed cortical neurons we demonstrated that ADD424042 decreased the maximal amplitude of voltage-gated sodium channels with an IC50 value in nM range. Moreover, the compound enhanced use-dependent block and decreased excitability in pyramidal neurons in the current-clamp experiments in cortical slices. Importantly, we found that ADD424042 possessed either no, or very small cardiotoxic effect. In contrast to DISO, ADD424042 did not produce any apparent changes in electrocardiogram (ECG) and arterial blood pressure recordings. ADD424042 had no effect on QT and corrected QT intervals, at a dose which was 15 times higher than ED50 for the anticonvulsant effect in the MES model. Taken together, these data suggest that ADD424042 has the potential to become a lead structure for novel broadly acting AEDs with wide margin of cardiac safety.

Disopyramide for Hypertrophic Cardiomyopathy: A Pragmatic Reappraisal of an Old Drug.

Hypertrophic cardiomyopathy (HCM) is a genetic cardiac disorder characterized by unexplained left ventricular hypertrophy in the absence of other cardiac or systemic etiologies. Approximately two-thirds of patients with HCM develop left ventricular outflow tract (LVOT) obstruction with or without provocation, whereas nearly half develop heart failure with preserved ejection fraction. Medical management of heart failure with preserved ejection fraction is based on the presence of symptoms and LVOT obstruction and frequently includes ß-blockers or verapamil. Disopyramide is a class Ia antiarrhythmic that historically was used for the treatment of arrhythmias; however, its contemporary use is often reserved for patients with HCM who are persistently symptomatic despite ß-blockers or verapamil and have evidence of LVOT obstruction. The pharmacologic rationale for use of disopyramide is largely based on its strong negative inotropic property. Three clinical studies have showed significant improvements in heart failure symptoms and a reduction in the need for invasive therapy in patients treated with disopyramide. Appropriate dosing and monitoring of disopyramide are important to mitigate the potential for anticholinergic adverse events and proarrhythmias. Disopyramide is a safe and effective medication that reduces heart failure symptoms and LVOT gradient and delays the need for invasive therapy in patients with obstructive HCM.

Advances in medical treatment of hypertrophic cardiomyopathy.

We reviewed the natural history of patients with hypertrophic cardiomyopathy (HCM). The effect of medical treatments on natural history, left ventricular (LV) functions and LV remodeling was also evaluated. Sudden cardiac death and end-stage heart failure are the most serious complications of HCM. Age <30 years and a family history of sudden premature death are risk factors for sudden cardiac death in HCM patients. End-stage heart failure is not a specific additional phenomenon observed in patients with HCM, but is the natural course of the disease in most of those patients. After the occurrence of heart failure, the progression to cardiac death is very rapid. Young age at diagnosis, a family history of HCM, and greater wall thickness are associated with a greater likelihood of developing end-stage heart failure. Neither beta-blockers nor calcium antagonists can prevent this transition. The class Ia antiarrhythmic drugs, disopyramide and cibenzoline are useful for the reduction of LV pressure gradient. Unlike disopyramide, cibenzoline has little anticholinergic activity; therefore, this drug can be easily adapted to long-term use. In addition to the reduction in LV pressure gradient, cibenzoline can improve LV diastolic dysfunction, and induce regression of LV hypertrophy in patients with HCM. A decrease in intracellular Ca(2+) concentration through the activation of the Na(+)/Ca(2+) exchanger associated with cibenzoline therapy is likely to be closely related with the improvement in HCM-related disorders. It is possible that cibenzoline can prevent the progression from typical HCM to end-stage heart failure.

Treatment of obstructive hypertrophic cardiomyopathy symptoms and gradient resistant to first-line therapy with ß-blockade or verapamil.

BACKGROUND: There is controversy about preferred methods to relieve obstruction in hypertrophic cardiomyopathy patients still symptomatic after ß-blockade or verapamil. METHODS AND RESULTS: Of 737 patients prospectively registered at our institution, 299 (41%) required further therapy for obstruction for limiting symptoms, rest gradient 61 ± 45, provoked gradient 115 ± 49 mm Hg, and followed up for 4.8 years. Disopyramide was added in 221 (74%) patients and pharmacological control of symptoms was achieved in 141 (64%) patients. Overall, 138 (46%) patients had surgical relief of obstruction (91% myectomy) and 6 (2%) alcohol septal ablation. At follow-up, resting gradients in the 299 patients had decreased from 61 ± 44 to 10 ± 25 mm Hg (P<0.0001); New York Heart Association class decreased from 2.7 ± 0.7 to 1.8 ± 0.5 (P<0.0001). Kaplan-Meier survival at 10 years in the 299 advanced-care patients was 88% and did not differ from nonobstructed patients (P=0.28). Only 1 patient had sudden death, a low annual rate of 0.06%/y. Kaplan-Meier survival at 10 years in the advanced-care patients did not differ from that expected in a matched cohort of the US population (P=0.90). CONCLUSIONS: Patients with obstruction and symptoms resistant to initial pharmacological therapy with ß-blockade or verapamil may realize meaningful symptom relief and low mortality through stepped management, adding disopyramide in appropriately selected patients, and when needed, by surgical myectomy.

A primer of disopyramide treatment of obstructive hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) occurs in 1 in 500 individuals. Treatment options for HCM differ from those administered in coronary disease, heart failure, and valvular disease patients that comprise the core of many cardiology practices. In this article, we offer a concise summary of the therapeutic use of disopyramide for reducing gradients and relieving symptoms in obstructive HCM.