Clinical significance of macroscopic T-wave alternans after sodium channel blocker administration in patients with Brugada syndrome

INTRODUCTION

Macroscopic T-wave alternans (TWA) is sometimes observed after sodium channel blocker administration in patients with Brugada syndrome (BS), but little is known about the association between occurrence of TWA and clinical characteristics in BS patients. We investigated the association between spontaneous ventricular fibrillation (VF) occurrence and TWA after pilsicainide, a sodium channel blocker administration in BS patients.

METHODS AND RESULTS

We administered pilsicainide at a dose of 1 mg/kg to 77 BS patients (76 males and one female; mean age, 48.4 years) and examined the association between TWA after pilsicainide administration and clinical characteristics, including age, spontaneous VF, syncope, family history of sudden death, spontaneous coved ST elevation, late potentials (LP), induction of VF by programmed electrical stimulation, and SCN5A mutation. None of the patients had TWA before pilsicainide administration, but TWA became apparent in 17 (22.1%) of the patients after pilsicainide administration. Patients with TWA had a significantly higher incidence of spontaneous VF (52.9% vs 8.3%, P < 0.001) and syncope (58.8% vs 26.7%, P < 0.05) than did patients without TWA. Then, we focused on the association between spontaneous VF and clinical characteristics. Patients with spontaneous VF had a significantly higher incidence of TWA (64.3% vs 12.7%, P < 0.001) and LP positive (92.9% vs 56.5%, P < 0.01) than did patients without spontaneous VF. In multivariate analysis, TWA (P = 0.001) and LP (P = 0.047) appeared as the independent predictor for spontaneous VF.

CONCLUSION

TWA after pilsicainide administration is associated with a high risk of clinical VF in patients with BS.

Living-donor lobar lung transplantation for pulmonary arterial hypertension after failure of epoprostenol therapy

OBJECTIVES

The aim of this study was to evaluate the long-term effects of living-donor lobar lung transplantation (LDLLT) for critically ill patients with pulmonary arterial hypertension (PAH) who failed in epoprostenol treatment.

BACKGROUND

Although continuous epoprostenol infusion has markedly improved survival in patients with PAH, some patients do not benefit from this therapy.

METHODS

From July 1998 to December 2003, 28 consecutive PAH patients who were treated with epoprostenol and accepted as candidates for lung transplantation were enrolled. All data were prospectively collected. As of July 2006, LDLLT was performed in 11 of those patients whose condition was deteriorating. Cadaveric lung transplantation (CLT) was performed in 2 patients. Medical treatment was continued in 15 patients.

RESULTS

There was no mortality in patients receiving LDLLT during a follow-up period of 11 to 66 months (average 48 months), and all patients returned to World Health Organization functional class I. Mean pulmonary artery pressure decreased from 62 +/- 4 mm Hg to 15 +/- 2 mm Hg (p < 0.001) at discharge and remained normal at 3 years. One CLT patient died of primary graft failure. Among medically treated patients, 6 patients died of disease progression. The survival rate was 100% at 5 years for patients receiving LDLLT, and 80% at 1 year, 67% at 3 years, and 53% at 5 years for patients medically treated (p = 0.028). All living donors have returned to their previous lifestyles.

CONCLUSIONS

These follow-up data support the option of LDLLT in patients with PAH who would die soon otherwise.

Intramyocardial Transplantation of Autologous CD34 + Stem Cells for Intractable Angina

BACKGROUND

A growing population of patients with coronary artery disease experiences angina that is not amenable to revascularization and is refractory to medical therapy. Preclinical studies have indicated that human CD34+ stem cells induce neovascularization in ischemic myocardium, which enhances perfusion and function.

METHODS AND RESULTS

Twenty-four patients (19 men and 5 women aged 48 to 84 years) with Canadian Cardiovascular Society class 3 or 4 angina who were undergoing optimal medical treatment and who were not candidates for mechanical revascularization were enrolled in a double-blind, randomized (3:1), placebo-controlled dose-escalating study. Patients received granulocyte colony-stimulating factor 5 microg x kg(-1) x d(-1) for 5 days with leukapheresis on the fifth day. Selection of CD34+ cells was performed with a Food and Drug Administration-approved device. Electromechanical mapping was performed to identify ischemic but viable regions of myocardium for injection of cells (versus saline). The total dose of cells was distributed in 10 intramyocardial, transendocardial injections. Patients were required to have an implantable cardioverter-defibrillator or to temporarily wear a LifeVest wearable defibrillator. No incidence was observed of myocardial infarction induced by mobilization or intramyocardial injection. The intramyocardial injection of cells or saline did not result in cardiac enzyme elevation, perforation, or pericardial effusion. No incidence of ventricular tachycardia or ventricular fibrillation occurred during the administration of granulocyte colony-stimulating factor or intramyocardial injections. One patient with a history of sudden cardiac death/ventricular tachycardia/ventricular fibrillation had catheter-induced ventricular tachycardia during mapping that required cardioversion. Serious adverse events were evenly distributed. Efficacy parameters including angina frequency, nitroglycerine usage, exercise time, and Canadian Cardiovascular Society class showed trends that favored CD34+ cell-treated patients versus control subjects given placebo.

CONCLUSIONS

A randomized trial of intramyocardial injection of autologous CD34+ cells in patients with intractable angina was completed that provides evidence for feasibility, safety, and bioactivity. A larger phase IIb study is currently under way to further evaluate this therapy.

Relationship between arrhythmogenesis and disease activity in cardiac sarcoidosis

BACKGROUND

In patients with cardiac sarcoidosis, ventricular arrhythmias and/or conduction disturbances are frequently observed and sometimes fatal. However, few reports on disease activity and arrhythmic events in cardiac sarcoidosis are available.

OBJECTIVE

The purpose of this study was to investigate the relationship between disease activity and arrhythmic events in cardiac sarcoidosis and the effect of corticosteroid therapy.

METHODS

The study population consisted of 15 cardiac sarcoidosis patients with new-onset symptomatic arrhythmia, including eight patients admitted once for complete atrioventricular block (CAVB), five patients admitted once for sustained ventricular tachycardia (VT), and two patients admitted twice for two arrhythmic events (one for CAVB and the other for sustained VT). Disease activity was evaluated by gallium-67 citrate (Ga) scintigraphy. All patients with positive Ga uptake were treated with corticosteroids, and arrhythmic events were evaluated by repeat Holter recordings.

RESULTS

Positive uptake of Ga was observed in 8 (80%) of the 10 CAVB events and in 1 (14%) of the 7 sustained VT events (80% vs 14%, P = .02). Corticosteroids abolished myocardial Ga uptake in all nine patients with positive Ga uptake. After corticosteroid therapy was started, AV conduction improved in 5 of 9 CAVB patients (including 8 patients with new-onset CAVB and one patient with history of CAVB). However, ventricular arrhythmias were not improved after corticosteroid therapy.

CONCLUSION

In cardiac sarcoidosis patients, CAVB develops mainly during the active phase of the disease. Early treatment with corticosteroids might improve AV conduction disturbance. However, sustained VT is not closely linked with disease activity and frequently develops in the advanced stage of disease.

Prevention of catheter-related infections using a closed hub system in patients with pulmonary arterial hypertension

BACKGROUND

Most of the patients with pulmonary arterial hypertension (PAH) receiving intravenous epoprostenol have experienced catheter-related infections during long-term treatment. Catheter hub was reported to be the most important source of catheter-related infections. To prevent the catheter-related infections, we have introduced a closed hub system and compared the incidence of catheter-related infections with that in patients using a non-closed hub system.

METHODS AND RESULTS

We evaluated the results obtained on 24 occasions in 20 patients with PAH between June 1999 and December 2005. On 11 occasions, a non-closed hub system was used and on 13 cases a closed hub system. We classified the catheter-related infection into a catheter-related bloodstream infection (CRBSI) group or a tunnel infection group based on the pathway of bacteria. The CRBSI rate was 0.89 per 1,000 catheter days in the non-closed hub system group vs 0.10 per 1,000 catheter days in the closed hub system group. Kaplan-Meier analysis showed that the risk of CRBSI significantly decreased in the closed hub system group. None of the patients died as a direct consequence of catheter-related infection during the study period.

CONCLUSIONS

We successfully prevented CRBSI by using a closed hub system.

The predictors of central and obstructive sleep apnoea in haemodialysis patients

BACKGROUND

Sleep apnoea (SA) is often observed in haemodialysis patients, but there have been few studies on types of SA and their predictors. We therefore investigated the prevalence and types of SA and the associations between types of SA and clinical factors in haemodialysis patients.

METHODS

We initially examined nocturnal oxygen desaturation index (ODI) (desaturation of >4%/events per hour) in 119 haemodialysis patients (68 males, mean age of 61.4 years). Patients with ODI of more than five were diagnosed as having SA. Then, 30 patients underwent polysomnography and we measured Apnoea-hypopnoea index (AHI), which was calculated as the number of apnoeas plus hypopnoeas per hour of sleep. Clinical characteristics were examined in all patients.

RESULTS

Forty-one (34.5%) of the 119 patients had SA. Twenty-seven (22.7%) of the 119 patients had SA with subjective symptoms such as daytime somnolence and snoring. There was a significant difference between body mass index (BMI) in patients with SA and that in patients without SA (22.5 vs 19.8 kg/m2, P<0.001). There were significantly higher prevalences of hypertension (85.4 vs 66.7%, P<0.05) and diabetes mellitus (36.6 vs 10.3%, P<0.01) in patients with SA than those in patients without SA. Multivariable analysis showed that BMI was independently associated with the occurrence of SA (OR 1.20, 95% CI 1.05-1.38). Mean AHI of 30 patients who underwent polysomnography was 53.2+/-28.9 [central apnoea, 4.1+/-5.6 (8%); obstructive apnoea, 21.7+/-21.5 (42%); mixed apnoea, 4.9+/-8.0 (9%); hypopnoea, 21.4+/-15.5 (41%)]. The number of obstructive apnoea events per hour was significantly correlated with BUN (r=0.490, P<0.01), Cr (r=0.418, P<0.05) and BMI (r=0.489, P<0.01) and was inversely correlated with serum bicarbonate (r=-0.646, P<0.01) and brain natriuretic peptide (BNP) (r=-0.481, P<0.01). The number of central apnoea events per hour was correlated inversely with PaO2 (r=-0.393, P<0.05) and PaCO2 (r=-0.388, P<0.05) and tended to be correlated with cardiothoracic ratio (CTR) (r=0.347, P=0.060).

CONCLUSIONS

There is a high prevalence of SA in haemodialysis patients. The dominant type of SA in haemodialysis patients is obstructive sleep apnoea (OSA). Uraemia (BUN, Cr), metabolic acidosis (serum bicarbonate) and BMI are good predictors of OSA. PaO2, PaCO2 and CTR are good predictors of central sleep apnoea (CSA). Good management of these factors might improve SA in haemodialysis patients.

Efficacy and Safety of the Additional Bepridil Treatment in Patients With Atrial Fibrillation Refractory to Class I Antiarrhythmic Drugs

BACKGROUND

Bepridil has multiple ion-channel blocking effects and is expected to be useful for managing atrial fibrillation (AF). The purpose of this study was to clarify the efficacy and safety of additional treatment with bepridil in patients with AF who had been treated with class I antiarrhythmic drugs (AADs).

METHODS AND RESULTS

Bepridil (50-200 mg/day) was given to 76 patients with either paroxysmal (n=49) or persistent AF (n=27). All patients had been treated with class I AADs (1.9+/-0.9 drugs/patient) that failed to control the AF. With the addition of bepridil, the frequency of symptomatic AF episodes decreased to less than 10% in 38 (78%) patients with paroxysmal AF, and sinus rhythm was restored within 3 months and maintained during the follow-up in 20 (74%) patients with persistent AF. Efficacy was usually obtained with a small to moderate dose (50-150 mg/day) of bepridil. During a mean follow-up period of 27+/-22 months, no potential complications occurred in any of the patients.

CONCLUSIONS

The addition of bepridil to class I AADs is effective and safe for AF, but careful observation using periodic ECG recordings is essential for avoiding torsades de pointes caused by QT prolongation.

Novel percutaneous catheter thrombectomy in acute massive pulmonary embolism: rotational bidirectional thrombectomy (ROBOT)

BACKGROUND

Although thrombolysis is a standard therapy in cases of pulmonary embolism (PE), fatal outcome is often observed. We designed and investigated the efficacy of a novel percutaneous catheter therapy, rotational bidirectional thrombectomy (ROBOT), for PE.

METHODS AND RESULTS

Eighteen patients with acute massive PE (Miller score > or = 20) were included in this study. We separated them into two groups [group A (n = 10), thrombolysis; group B (n = 8): thrombolysis and ROBOT or ROBOT alone]. There was no difference in the hemodynamic indices between the groups at diagnosis. ROBOT was designed to fragment emboli by rotating a regular pigtail catheter. Three deaths occurred in group A because of hemodynamic impairment, but there was no death in group B. One day after treatment, systolic pulmonary artery pressure had decreased from 53 +/- 8 to 30 +/- 8 mm Hg (P < 0.05) in group B and from 54 +/- 5 to 42 +/- 19 mm Hg (NS) in group A. The hospitalization period in group B was shorter than that in group A (17 +/- 6 vs. 27 +/- 10 days, P < 0.05).

CONCLUSION

ROBOT therapy results in a significant, rapid improvement in the hemodynamic situation and in a better outcome than conventional therapy in patients with acute massive pulmonary embolism.

Aldosterone synthesis and cytokine production in human peripheral blood mononuclear cells

Previously, we reported that spironolactone reduced cytokine production in cultured human peripheral blood mononuclear cells (PBMCs) with angiotensin (Ang) II stimulation. To address the mechanisms underlying this effect, we examined the contribution of aldosterone to cytokine production in cultured human PBMCs with Ang II stimulation. PBMCs expressed the messenger RNA (mRNA) of Ang II type 1 receptor (AT1R) and mineralocorticoid receptor (MR) both spontaneously and after Ang II stimulation, but expressed Ang II type 2 receptor (AT2R) under neither condition. After 24 h of incubation, exogenous Ang II induced the expression of CYP11B2 (a key enzyme of aldosterone synthesis) mRNA and caused aldosterone synthesis. CV-11974 (an AT1R antagonist) reduced Ang II-induced aldosterone synthesis, whereas PD-123319 (an AT2R antagonist) had no effect. The concentration of aldosterone peaked earlier than those of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF-alpha). After 48 h of incubation (under the influence of synthesized aldosterone), CV-11974 and spironolactone significantly reduced the Ang II-enhanced production of MCP-1 and TNF-alpha, whereas PD-123319 also had no effect. In conclusion, Ang II induces aldosterone synthesis through AT1R and enhances cytokine production through an AT1R-dependent mechanism and, at least partly, through a MR-dependent mechanism in human PBMCs.

Elevated levels of oxidative DNA damage in serum and myocardium of patients with heart failure

BACKGROUND

Oxidative stress has been implicated in the pathogenesis of chronic heart failure. The present study investigated whether the levels of 8-hydroxy-2-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, were elevated in the serum and myocardium of patients with dilated cardiomyopathy (DCM), and furthermore whether carvedilol, a vasodilating beta-blocker with antioxidant activity, could reduce the levels.

METHODS AND RESULTS

Serum levels of 8-OHdG were measured by enzyme immunoassay in 56 patients with DCM and in 20 control subjects. DCM patients had significantly elevated serum levels of 8-OHdG compared with control subjects. Endomyocardial biopsy samples obtained from 12 DCM patients and 5 control subjects with normal cardiac function were studied immunohistochemically for the expression of 8-OHdG. Positive 8-OHdG staining was found in the nuclei of cardiomyocytes from DCM patients but not in those from control subjects. After treatment with carvedilol, the serum levels of 8-OHdG in DCM patients significantly decreased by 19%, together with amelioration of heart failure.

CONCLUSIONS

Levels of 8-OHdG are elevated in the serum and myocardium of patients with heart failure. Treatment with carvedilol might be effective for decreasing the oxidative DNA damage.

Carvedilol inhibits proliferation of cultured pulmonary artery smooth muscle cells of patients with idiopathic pulmonary arterial hypertension

Idiopathic pulmonary arterial hypertension (IPAH) is associated with proliferation of smooth muscle cells (SMCs) in small pulmonary arteries. Inhibition of proliferation of pulmonary artery smooth muscle cells (PASMCs) may be an effective treatment of patients with idiopathic pulmonary arterial hypertension. Recent studies have shown that carvedilol, an alpha- and beta-blocker with antioxidant and calcium channel blocking properties, inhibits the proliferation of cultured normal human pulmonary artery smooth muscle cells. In this study, we tested the hypothesis that carvedilol has antiproliferative effects on pulmonary artery smooth muscle cells of patients with idiopathic pulmonary arterial hypertension. Pulmonary artery smooth muscle cells from six idiopathic pulmonary arterial hypertension patients who had undergone lung transplantation were cultured. To determine cell proliferation, H-thymidine incorporation was measured. Platelet-derived growth factor-induced proliferation of IPAH-PASMCs was significantly greater than that of normal control pulmonary artery smooth muscle cells. Carvedilol (0.1 microM to 10 microM) inhibited the proliferation of idiopathic pulmonary arterial hypertension-pulmonary artery smooth muscle cells in a concentration-dependent manner. Prazosin (an alpha-blocker) and N-acetyl L cysteine (an antioxidant agent) (0.1 microM to 10 microM) did not inhibit their proliferation, but the high concentration of propranolol (a beta-blocker) and nifedipine (a calcium channel blocker) (10 microM) inhibited the proliferation. The combination of propranolol and nifedipine inhibited the proliferation but only at a high concentration (10 microM) combination. Cell cycle analysis revealed that carvedilol (10 microM) significantly decreased the number of cells in S and G2/M phases. These results indicate that carvedilol inhibits the exaggerated proliferation of pulmonary artery smooth muscle cells of patients with idiopathic pulmonary arterial hypertension partially via its beta-blocking [corrected] and calcium channel blocking effects in vitro.

Anti-inflammatory effect of spironolactone on human peripheral blood mononuclear cells

We evaluated the effect of alacepril, CV-11974, and spironolactone on the production of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF-alpha) in cultured human peripheral blood mononuclear cells stimulated with angiotensin (Ang) II. Alacepril, CV-11974, and spironolactone significantly reduced the enhanced production of MCP-1 and TNF-alpha induced by exogenous Ang II. Specifically, 10 muM of spironolactone significantly reduced cytokine production, compared to the same dose of alacepril or CV-11974. These findings indicate that spironolactone may contribute to ameliorate the prognosis of patients with cardiovascular diseases by reducing Ang II-induced inflammation, although further exploration including determining the mechanisms would be required.

Low-dose isoproterenol for repetitive ventricular arrhythmia in patients with Brugada syndrome

AIMS

Arrhythmic storm or repetitive ventricular arrhythmia (VA) has been occasionally observed in Brugada syndrome (BS). A beta-adrenergic stimulator [isoproterenol (ISP)] has been reported to suppress this arrhythmic storm in sporadic cases. Accordingly, we investigated the antiarrhythmic effects of ISP infusion in consecutive BS patients with arrhythmic storm or repetitive VA.

METHODS AND RESULTS

Seven BS patients with arrhythmic storm were studied. Intravenous ISP was administered as a bolus injection (1-2 microg), followed by continuous infusion (0.15 microg/min). Arrhythmic storm or repetitive VA was suppressed immediately after the bolus administration of ISP, which was followed by continuous infusion of low-dose ISP for 1-3 days. In all patients, ST-elevation decreased in right precordial leads. In six of the seven patients, VA subsided after the discontinuance of ISP. RR interval was shortened and ST-elevation in right precordial leads was decreased after ISP bolus injection. ST-elevation in right precordial leads remained decreased during continuous ISP infusion, whereas the RR interval returned to the control level.

CONCLUSION

Continuous administration of low-dose ISP may be effective for the suppression of repetitive VA occurrence in patients with BS.

Hepatocyte growth factor gene therapy reduces ventricular arrhythmia in animal models of myocardial ischemia

It was recently reported that gene therapy using hepatocyte growth factor (HGF) has the potential to preserve cardiac function after myocardial ischemia. We speculated that this HGF gene therapy could also prevent ventricular arrhythmia. To investigate this possibility, we examined the antiarrhythmic effect of HGF gene therapy in rat acute and old myocardial infarction models. Myocardial ischemia was induced by ligation of the left descending coronary artery. Hemagglutinating virus of Japan (HVJ)-coated liposome containing HGF genes were injected directly into the myocardium fourteen days before programmed pacing. Ventricular fibrillation (VF)was induced by programmed pacing. The VF duration was reduced and the VF threshold increased after HGF gene therapy ( p< 0.01). Histological analyses revealed that the number of vessels in the ischemic border zone was greatly increased after HGF gene injection. These findings revealed that HGF gene therapy has an anti-arrhythmic effect after myocardial ischemia.

Prednisolone inhibits proliferation of cultured pulmonary artery smooth muscle cells of patients with idiopathic pulmonary arterial hypertension

BACKGROUND

Idiopathic pulmonary arterial hypertension (IPAH) is associated with proliferation of smooth muscle cells (SMCs) in small pulmonary arteries. There is no therapy that specifically inhibits SMC proliferation. Recent studies reported that prednisolone (PSL) inhibits the postangioplasty proliferation of SMCs in atherosclerotic arteries. In this study, we tested the hypothesis that PSL has antiproliferative effects on pulmonary artery SMCs of patients with IPAH.

METHODS AND RESULTS

Pulmonary artery SMCs were harvested from the pulmonary arteries of 6 patients with IPAH who underwent lung transplantation. Control SMCs were obtained from 5 patients with bronchogenic carcinoma who underwent lung lobectomy. After incubation in the presence of platelet-derived growth factor (PDGF), PSL was added at different concentrations and cell proliferation was assessed by 3H-thymidine incorporation. PSL (2x10(-4) and 2x10(-3) mol/L) significantly inhibited PDGF-stimulated proliferation (P<0.05) of SMCs from patients with IPAH but did not affect cell viability of SMCs, as confirmed by trypan blue staining. In cell cycle analysis using a microscope-based multiparameter laser scanning cytometer, PSL inhibited the progression of SMCs from G(0)/G1 to the S phase. This inhibition was associated with increased p27 expression level. PSL (2x10(-4) mol/L) also inhibited PDGF-induced SMC migration.

CONCLUSIONS

Our results indicate that PSL has an antiproliferative effect on cultured SMCs of pulmonary arteries from patients with IPAH and suggest that PSL may be potentially useful therapeutically in patients with IPAH.

Relationship between oxidative stress and systolic dysfunction in patients with hypertrophic cardiomyopathy

BACKGROUND

Progression of hypertrophic cardiomyopathy (HCM) to left ventricular dilatation and systolic dysfunction sometimes occurs. However, the mechanism is not known. We examined whether oxidative stress was elevated in myocardia of HCM patients and whether the levels were correlated with left ventricular dilatation and systolic dysfunction.

METHODS AND RESULTS

Endomyocardial biopsy samples obtained from the right ventricular side of the septum of 31 patients with HCM, and 10 control subjects were studied immunohistochemically for the expression of 4-hydroxy-2-nonenal (HNE)-modified protein, which is a major lipid peroxidation product. Expression of HNE-modified protein was found in all myocardial biopsy samples from patients with HCM. Expression was distinct in the cytosol of cardiomyocytes. The expression levels in patients with HCM were significantly increased compared with those in control subjects (P = .0005). The expression levels in patients with HCM were correlated with left ventricular end-diastolic diameter (r = 0.483, P = .0053) and end-systolic diameter (r = 0.500, P = .0037) determined by echocardiography. The expression levels were inversely correlated with left ventricular ejection fraction determined by left ventriculography (r = -0.640, P = .0001).

CONCLUSION

Oxidative stress was elevated in myocardia of HCM patients and the levels were correlated with left ventricular dilatation and systolic dysfunction. Oxidative stress is involved in the pathogenesis of heart failure in patients with HCM.

[Long QT syndrome]

The long QT syndrome (LQTS) is characterized by prolongation of the QT interval, causing torsade de pointes and sudden cardiac death. This syndrome can be divided into idiopathic (congenital) and acquired forms. The idiopathic form is a familial disorder that can be associated with sensorineural deafness (Jervell and Lange--Nielsen syndrome, autosomal recessive) or normal hearing (Romano--Ward syndrome, autosomal dominant). The acquired form has a long QT interval caused by various drugs such as quinidine sotalol and dofetilide, also by noncardiovascular drugs such as antihistamine, antibiotics, antipsychotics and others. Also, the QT interval is prolonged by electrolyte abnormalities such as hypokalemia and hypomagnesemia, central nervous system lesions, significant bradyarrhythmias, cardiac ganglionitis, mitral valve prolapse and probucol. DNA variants appearing to predispose to drug-associated acquired long QT syndrome have been reported in congenital long QT.