P418 CARDIOMETABOLIC ALTERATIONS IN OBESE PATIENTS WITH OBSTRUCTIVE SLEEP APNEA SYNDROME

Background

Obesity and Obstructive Sleep Apnea Syndrome (OSAS) has been recognized as two of the major cardiac risk factors and they often coexist in one patient. OSAS increase the risk of as myocardial infarction, heart failure and arrhythmias. On the other hand, obesity is and independent predictor of cardiovascular mortality since it causes insulin resistance, dyslipidemia, sympathetic hyperactivation, chronic inflammation and endothelial dysfunction.

Aim

To evaluate cardiometabolic profile, echocardiographic alterations and the presence of arrhythmias in obese patients with Obstructive Sleep Apnea Syndrome and non obese patients.

Patients and Methods

67 obese patients (37 male/30 female) and 52 non obese patients (40 male/12 female) were enrolled. All subjects underwent anthropometrical evaluation and a venous blood sample for biochemical and hormonal determinations including fasting plasma glucose, fasting plasma insulin, Hba1c and OGTT to 5 hours. The insulin resistance was evaluated by HOMA–IR. All the patients underwent echocardiographic examination, polysomnographic evaluation, in order to diagnose the OSAS, and a simultaneous 12–lead Holter ECG to evaluate the presence of nocturnal arrhythmias.

Results

As expected, we found a better antropometrics profile in non obese patients. Obese patients display a severe OSAS compared to non–obese patient as shown by higher values of AHI (26.37 ±24.95 vs 16.58 ±14.07; P < 0.05), TC90 (19.61 ±24.45 vs 8.63 ±17.80; P < 0.05) and ODI (40.55 ±27.41 vs 21.06 ±22.78; P < 0,05). In obese patients we also found a significant reduction of both ejection fraction (55.54 ±7.97 vs 66.52 ±8.95; P < 0.05) and A–wave (0.75 ±0.17 vs 0.83 ±0.19; P < 0.05). In 20% of obese patients, 12–lead Holter ECG showed the presence of cardiac pause > 3 sec during apnea. In obese population alone we demonstrated a significant negative correlation between AHI and E–wave (r= –0.3; P = 0.04) and a positive correlation with interventricular septum (r = 0.38; P = 0.01) and left ventricular mass (r = 0.32; P = 0.02). Post–hoc analysis shown how these findings maintained statistical significance even when the obese patients were stratified in subgroups according to the severity of OSAS.

Conclusions

Our data, even if preliminary, seem to indicate that OSAS is not only linked to obesity but it also acts as a negative factor on the cardiometabolic risk.

P386 OBESITY AND CARDIOMYOPATHY

Background

Obesity cardiomyopathy is a heart failure unexplained by others etiologies that can vary from a subclinical left ventricular dysfunction to overt dilated cardiomyopathy.

Aim

To evaluate the changes in echocardiogram in both normotensive and hypertensive obese and to evaluate obesity and/or hypertension impact on cardiomyopathy.

Methods

383 subjects (236F–147M) were enrolled. They were divided into two groups based on BMI: non–obese subjects (BMI<30kg/m2) and obese subjects (BMI>30kg/m2). The obese subjects were divided in different degrees (groups) of obesity according with obesity classification: group 1= BMI >30<35, 2= BMI >35<40, 3= BMI >40 kg/m2. 208 of 383 enrolled subjects were hypertensive. All subjects underwent to an echocardiogram with evalutation of left atrial diameter (LAD), left ventricular end–diastolic diameter (LVEDD), left ventricular end–systolic diameter (LVESD), ventricular septum, cardiac mass and left ventricular mass index (LVMI).

Results

Obese subjects showed a progressive increase in left atrial diameter (LAD)(P = 0.000), left ventricular end–diastolic diameter (LVEDD)(P = 0.000), left ventricular end–systolic diameter (LVESD)(P = 0.001), ventricular septum (P = 0.000) and cardiac mass (P = 0.000) according to the degree of obesity. Subjects in the 3° group of obesity showed higher value of LAD and LVESD when compared with subjects in first two groups (P = 0.000; P = 0.032; P = 0.000; P = 0.001, respectively). Similarly, subjects in the 3° group of obesity showed higher value of ventricular septum and cardiac mass when compared with the first two groups of obesity (P = 0.005; P = 0.002; P = 0.000; P = 0.005; respectively). LAD, LVEDD, LVESD, ventricular septum and cardiac mass were positively related with the obesity degree. In order to avoid that echocardiographic modifications were caused by hypertension, data were adjusted for hypertension so linear regression documented that degree of obesity predicts echocardiographic changes (LAD, LVEDD, LVESD) better than hypertension.

Conclusions

Our data suggested that the in obese subjects the severity of cardiomyopathy is correlated with degree of obesity and that the degree of obesity is a better predictor than hypertension for echocardiographic changes.

C72 THE EFFECTS OF BATRIATIC SURGERY ON CARDIO–METABOLIC PROFILE AND CARDIAC REMODELING

Background

Obesity is associated with cardiac remodeling resulting in hypertrophy of the left ventricle (LV) with a predominantly concentric pattern. LV remodeling and fibrosis induce mechanical and electrical dysfunction of the myocardial tissue, an increase in cardiac output, an increase of myocardial workload and mean arterial pressure.

Objective

To evaluate the impact of bariatric surgery, and therefore of anthropometric and cardio–metabolic variations, on cardiac structure and function.

Methods

Twenty–six obese patients treated with bariatric surgery were enrolled. All the patients at baseline and at 6 and 12 months underwent a complete anthropometrical evaluation, laboratory determinations and echocardiogram evaluation. The IR has been assessed by HOMA–IR. The patients were divided into two groups: the first group (8 patients) carried out a follow–up at 6 months post–surgery; the second group (18 patients) at 12 months post–surgery.

Results

As expected, an improvement in the anthropometric and metabolic profile in patients treated with bariatric surgery was observed. Echocardiographic data showed a significant increase in the Ejection Fraction (P < 0.001) and the E/A Ratio (P < 0.001) 6 months after bariatric surgery, a significant reduction in the Interventricular Septum thickness at 6 months (P < 0.001) and at 12 months (P < 0.002) post–surgery and a significant reduction in the Left Ventricular Mass at 6 months (P = 0.02) and at 12 months (P = 0.05) after bariatric surgery. A reduction no significant in the Left Ventricular posterior wall thickness has been observed.

Conclusions

Our data showed an increase of the systolic function, an increase of the left ventricular diastolic compliance and a reduction in subclinical cardiac organ damage. Therefore, significant weight loss obtained with bariatric surgery may lead to reverse cardiac remodeling, associated with beneficial effects on myocardial structure and systo-diastolic function.

C77 EFFECT OF SACUBITRIL/VALSARTAN ON BOTH METABOLIC PARAMETER AND INSULIN RESISTANCE IN NON OBESE NON DIABETIC PATIENTS WITH HEART FAILURE

Background

Sacubitril/Valsartan has been shown to improve mortality and reduce hospitalizations in patients with heart failure with reduced ejection fraction (HFrEF). Moreover Sacubitril/Valsartan showed a significantly reduction in the HbA1c in diabetic patients. The effect of Sacubitril/Valsartan on metabolic parameter and insulin resistence in both, non obese and non diabetic patients, have not been previously described.

Aim

We evaluated the effects of the Sacubitril/Valsartan on both glycaemic and metabolic parameter, on HOMA–IR and on echocardiographic parameters in patients with HFrEF.

Methods

A total of 59 non obese and non diabetic patients with a diagnosis of HFrEF (EF < 35%) have been enrolled. All the patients underwent a complete anthropometrical evaluation, laboratory determinations (including fasting glucose, fasting insulin, HbA1c) and echocardiogram evaluation. Data analysis was made after 24 weeks of treatment. The insulin resistance has been assessed by HOMA–IR.

Results

Data analysis demostrated a significant reduction in fasting plasma glucose (111.4 + 11.5 vs 106 + 10 mg/dl, P = 0.03), fasting plasma insulin (13.6 + 5.9 vs 10.5 + 4.4 µUI/ml), HbA1c value (6.14 + 0.5% vs 5.9 + 0.3%, P < 0.01) and insulin resistance (HOMA–IR, 3.74 + 2.2 vs 2.7 + 2.1, P = 0.03). The echocardiogram evaluation showed a significant reduction of the end–diastolic left ventricular volume (168 + 44 vs 150 + 38 ml, P < 0.05), a no significant reduction of the end–systolic left ventricular volume (98 + 26 vs 88 + 22 ml, P = 0.07), a significant reduction of E/e1 ratio and an average 7.8% increase in ejection fraction (EF), from a mean baseline of 32.3 + 2.4 to 40.1 + 3.8% (P < 0.0001). No differences in interventricular septal (IVS) thickness, posterior wall (PW) thickness, A–wave, E–wave and E/A ratio have been observed. No differences in anthropometrical parameters (weight, body mass index, waist circumference) and blood pressure were observed.

Conclusions

Our data, even if preliminary, seem to indicate that sacubitril/valsartan might enhance glycaemic control and improve insulin resistance in non obese/non diabetic patients with HFrEF. Also, our data confirm that sacubitril/valsartan treatment is able to improve ejection fraction in HFrEF patients.

Effects of sacubitril/valsartan on both metabolic parameters and insulin resistance in prediabetic non-obese patients with heart failure and reduced ejection fraction

BACKGROUND

The effects of sacubitril/valsartan (sac/val) on metabolic parameters and insulin resistance (IR) in non-obese/prediabetic patients have not been previously described.

AIM

To evaluate the effects of sac/val on glycemic and metabolic parameters, Homeostatic Model Assessment of IR (HOMA-IR), and echocardiographic parameters in prediabetic patients with heart failure with reduced ejection fraction (HFrEF).

METHODS

Fifty-nine patients with HFrEF (EF < 35%) but without obesity and/or type 2 diabetes mellitus have been enrolled. All the patients at baseline and week 24 underwent complete anthropometrical evaluation and were subjected to an echocardiogram test. IR has been assessed by HOMA-IR.

RESULTS

After 24-week of treatment with sac/val, a significant reduction in fasting plasma glucose (109 ± 9 vs 103 ± 8 mg/dl, p < 0.0001), fasting plasma insulin (16 ± 4 vs 10 ± 4 UI/L), and hemoglobin A1c (HbA1c) value (6% ± 0.5% vs 5.3% ± 0.3%, p < 0.0001) was observed. Similarly, we observed a significant improvement in IR (HOMA-IR, 4.4 ± 0.9 vs 2.5 ± 0.6, p < 0.0001). The echocardiogram evaluation showed a significant reduction of the left ventricular end-diastolic volume (168 ± 24 vs 158 ± 22 ml, p < 0.05), a significant reduction of the left ventricular end-systolic volume (111 ± 26 vs 98 ± 22 ml, p < 0.005), and a significant reduction of E/e' ratio. Sac/val use was also associated with an average 5.1% increase in ejection fraction.

CONCLUSIONS

Our data seem to indicate that sal/val enhances metabolic control and improves insulin resistance also in prediabetic non-obese patients with HFrEF.

Clinical Discussions in Antithrombotic Therapy Management in Patients With Atrial Fibrillation: A Delphi Consensus Panel

Background

In recent years, direct-acting oral anticoagulants (DOACs) have entered clinical practice for stroke prevention in non-valvular atrial fibrillation or prevention and treatment of venous thromboembolism. However, remaining uncertainty regarding DOAC use in some clinical scenarios commonly encountered in the real world has not been fully explored in clinical trials.

Methods

We report on use of a Delphi consensus process on DOAC use in non-valvular atrial fibrillation patients. The consensus process dealt with 9 main topics: (i) DOACs vs vitamin K antagonists in atrial fibrillation (AF) patients; (ii) therapeutic options for patients with stable total time in range treated with vitamin K antagonists; (iii) therapeutic options for patients aged > 85 years; (iv) therapeutic management of hyperfiltering patients; (v) pharmacologic interactions; (vi) therapeutic options in the long-term treatment (prevention) of patients with AF and acute coronary syndrome after the triple therapy; (vii) low doses of DOACs in AF patients; (viii) ischemic stroke in patients inappropriately treated with low doses of DOACs; (ix) management of patients taking DOACs with left atrial appendage thrombosis.

Results

A total of 101 physicians (cardiologists, internists, geriatricians, and hematologists) from Italy expressed their level of agreement on each statement by using a 5-point Likert scale (1 = strongly disagree; 2 = disagree; 3 = somewhat agree; 4 = agree; 5 = strongly agree). Votes 1-2 were considered to be disagreement; votes 3-5 were considered to be agreement. Agreement among the respondents of ≥ 66% for each statement was considered consensus. A brief discussion of the results for each topic is also reported.

Conclusions

In clinical practice, there is still uncertainty on DOAC use, especially in elderly, fragile, comorbid, and hyperfiltering patients.

Liraglutide improves cardiac function in patients with type 2 diabetes and chronic heart failure

PURPOSE

To compare the effect of liraglutide, sitagliptin and insulin glargine added to standard therapy on left ventricular function in post-ischemic type-2 diabetes mellitus patients.

METHODS

We evaluated 32 type-2 diabetes mellitus Caucasians with history of post-ischemic chronic heart failure NYHA class II/III and/or left ventricular ejection fraction ≤45 %. Participants underwent laboratory determinations, electrocardiogram, echocardiogram, Minnesota Living with Heart Failure questionnaire and 6 min walking test at baseline and following 52 weeks treatment. Patients were treated with standard therapy for chronic heart failure and were randomized to receive liraglutide, sitagliptin and glargine in addition to metformin and/or sulfonylurea.

RESULTS

Liraglutide treatment induced an improvement in left ventricular ejection fraction from 41.5 ± 2.2 to 46.3 ± 3 %; P = 0.001). On the contrary, treatment with sitagliptin and glargine induced no changes in left ventricular ejection fraction (41.8 ± 2.6 vs. 42.5 ± 2.5 % and 42 ± 1.5 vs. 42 ± 1.6 %, respectively; P = NS). Indexed end-systolic LV volume was reduced only in liraglutide-treated patients (51 ± 9 vs. 43 ± 8 ml/m²; P < 0.05). Liraglutide treatment induced also a significant increase in the anterograde stroke volume (39 ± 9 vs. 49 ± 11 ml; P < 0.05), whereas no differences were observed in the other two groups. Cardiac output and cardiac index showed a significant increase only in liraglutide-treated patients (4.4 ± 0.5 vs. 5.0 ± 0.6 L/min; P < 0.05 and 1.23 ± 0.26 vs. 1.62 ± 0.29 L/m²; P = 0.005, respectively). Liraglutide treatment was also associated with an improvement of functional capacity and an improvement of quality of life.

CONCLUSIONS

These data provide evidence that treatment with liraglutide is associated with improvement of cardiac function and functional capacity in failing post-ischemic type-2 diabetes mellitus patients.

[Data from the IN-HF Outcome registry]

The IN-HF Outcome registry enrolled 1855 patients admitted for acute heart failure and 3755 outpatients with chronic heart failure seen at 64 cardiology units of the Italian Network-Heart Failure. We assessed gender-related differences in clinical characteristics, management, and short- and long-term mortality and morbidity outcomes. Women were older, more often hypertensive and with a higher prevalence of heart failure with preserved systolic function. Aggressive management was less frequent in women who underwent less often diagnostic and therapeutic procedures. We found no gender-related differences in either acute or long-term mortality nor in hospital readmissions.

[Hyperglycaemia and Acute Coronary Syndrome]

Hyperglycaemia in patients with Acute Coronary Syndrome (ACS)is common, and is an independent predictor of mortality and morbidity in patients both with and without diabetes mellitus. Hyperglycaemia may be a marker of pre-existing diabetes or glucose intolerance or may also represent a transient stress response mediated through the autonomic nervous system with release of adrenal corticosteroids and catecholamines. Several evidences suggest that an intensive control of hyperglycaemia results in a significant improvement of the adverse outcomes in the short and long term. In fact, an intensive metabolic treatment can counteract the negative effects of hyperglycaemia. However, the main difficulty to intensive glucose control in patients with ACS remains hypoglycaemia that is associated with an increased risk of mortality and myocardial re-infarction. No definitive data are available about the beneficial effects of insulin intensive treatment. Therefore, randomized multicenter clinical trials will be needed to definitively establish whether intensive glucose control will reduce the associated increased mortality rate and higher rates of complications in hospitalized ACS patients with hyperglycaemia.

Relationship between angiotensin-converting enzyme gene polymorphism and insulin resistance in never-treated hypertensive patients

The association between angiotensin-converting enzyme (ACE) gene polymorphism and insulin resistance (IR) in hypertensive subjects remains controversial. Thus, we evaluated the possible association between IR and ACE gene polymorphism in a group of hypertensive, never-treated patients compared with that in a normotensive control group. We enrolled 200 (114 men and 86 women; age, 45.5 +/- 4.7 yr) hypertensive patients and 96 (54 men and 42 women; age, 44.0 +/- 4.7 yr) normotensive subjects. A double PCR assay was used to identify ACE genotypes. We determined fasting glucose and insulin by the glucose oxidase method and using a standard RIA technique. IR was estimated using the homeostasis model assessment (HOMA(IR)). Both fasting glucose (5.0 +/- 0.3 vs. 4.7 +/- 0.3 mmol/L; P < 0.0001), insulin levels (12.3 +/- 4.7 vs. 4.9 +/- 1.5 muU/mL; P < 0.0001), and HOMA(IR) (2.7 +/- 1.1 vs. 1.1 +/- 0.3; P < 0.0001) were significantly higher in hypertensive patients than in the normotensive control group. When we subdivided hypertensive patients according to ACE genotype, we observed that fasting insulin and HOMA(IR) were 16.3 +/- 3.3 and 3.6 +/- 0.8 in the DD genotype, 9.4 +/- 3.1 and 2.1 +/- 0.7 in the ID genotype, and 8.3 +/- 2.8 and 1.9 +/- 0.7 muU/mL in the II group (P < 0.0001, by ANOVA). No significant differences were observed in the normotensive control group. In conclusion, we extended previous data regarding the relationship of hypertension and IR by demonstrating a dependence of this relationship upon the ACE gene polymorphism.

Effects of atorvastatin and vitamin C on endothelial function of hypercholesterolemic patients

We tested the effects of vitamin C and atorvastatin treatment on endothelium-dependent and endothelium-independent vasodilation in 18 hypercholesterolemic patients (ten men and eight women, aged 20-46 years) in comparison with 12 normal volunteers (seven men and five women, aged 20-45 years). The responses of the forearm blood flow (FBF) to acetylcholine (ACh) (7.5, 15 and 30 microg/min), sodium nitroprusside (SNP) (0.8, 1.6, 3.2 microg/min) and L-NMMA (2, 4, 8 micromol/min) were evaluated at baseline and after 1 month of atorvastatin (10 mg/day) treatment. Drugs were infused into the brachial artery and FBF was measured by strain-gauge plethysmography. At baseline, the response to ACh was significantly attenuated in hypercholesterolemics versus controls: at the highest dose (30 microg/min), FBF was 27.0+/-3.4 versus 11.5+/-1.9 ml.100 ml tissue(-1).min(-1) respectively (P<0.0001). No significant differences were found between groups during SNP infusion. The atorvastatin treatment significantly improved ACh-stimulated FBF: at highest dose the FBF increased to 14.9+/-1.5 ml.100 ml tissue(-1). min(-1) (P<0.0001). Similarly, the L-NMMA endothelial effects were significantly enhanced by lipid-lowering treatment, supporting the improvement of basal nitric oxide. Vitamin C increased ACh-vasodilation in the same way before and after atorvastatin treatment. In conclusion, the endothelial dysfunction in hypercholesterolemics is due to an oxidative stress and atorvastatin rapidly improves both basal and stimulated endothelium-dependent vasodilation.

Relationship between left ventricular mass and endothelium-dependent vasodilation in never-treated hypertensive patients

BACKGROUND

Hypertensive patients are characterized by development of both left ventricular hypertrophy (LVH) and endothelial dysfunction

METHODS AND RESULTS

We enrolled 65 never-treated hypertensive patients (36 men and 29 women aged 45.6+/-6.0 years) to assess the possible relationship between echocardiographic left ventricular mass (LVM) and endothelium-dependent vasodilation. Left ventricular measurements were performed at end diastole and end systole according to the recommendations of the American Society of Echocardiography and the Penn Convention. LVM was calculated with the Devereux formula and indexed by body surface area and height raised to the 2.7th power. The endothelial function was tested as responses of forearm vasculature to acetylcholine (ACh), an endothelium-dependent vasodilator (7.5, 15, and 30 microg. mL-1. min-1, each for 5 minutes), and sodium nitroprusside (SNP), an endothelium-independent vasodilator (0.8, 1.6, and 3.2 microg. mL-1. min-1, each for 5 minutes). Drugs were infused into the brachial artery, and forearm blood flow (FBF) was measured by strain-gauge plethysmography. A negative significant relationship between indexed LVM and peak of increase in FBF was found during ACh infusions (r=-0. 554; P<0.0001). In addition, hypertrophic patients had a significantly lower responsive to ACh than patients without LVH (the peak increase in FBF was 9.9+/-3.7 versus 16.1+/-8.1 mL per 100 mL of tissue per minute; P<0.0001). No significant correlation was observed between LVM and FBF during SNP infusion.

CONCLUSIONS

Our data provide the first evidence that echocardiographic LVM in hypertensive patients is inversely related to FBF responses to the endothelium-dependent vasodilating agent ACh, but it is likely that both endothelium and LVM are damaged by hypertension.

Evaluation of antihypertensive effects of once-a-day isradipine and fosinopril: a double-blind crossover study by means of ambulatory blood pressure monitoring

We compared the efficacy and tolerability of isradipine (ISR) and fosinopril (FOS) once-a-day administration in 17 outpatients, 9 men and 8 women, aged 35-65 years (mean +/- SD = 58 +/- 10 years), affected by mild to moderate primary systemic hypertension. The patients were given single-blind placebo for 2 weeks and thereafter, in double-blind, randomized, crossover sequence, ISR (5 mg) and FOS (20 mg), both for 4 weeks. At the end of each period, patients underwent 24-h noninvasive blood pressure (BP) monitoring by means of an A&D TM 2420 Monitor Model 7, with readings taken very 10 min during the day (from 7 A.M. to 11 P.M.), and every 20 min during the night (from 11 P.M. to 7 A.M.) Similarly, BP load (BPL) as percentage of systolic and diastolic BP reading > 140 and > 90 mmHg was investigated. Both ISR and FOS induced a highly significant (p < 0.0001) decrease in BP from 158/96 +/- 7/6 mmHg to 133/86 +/- 6/6 and to 132/83 +/- 10/7 mmHg, respectively. Mean BP decreased from 117 +/- 6 mmHg to 102 +/- 6 mmHg (ISR) (p < 0.0001) and to 99 +/- 8 mmHg (FOS) (p < 0.0001). Both ISR and FOS significantly (p < 0.0001) reduced systolic BPL from 78 +/- 16% to 44 +/- 13% and 28 +/- 12%, respectively, and diastolic BPL from 70 +/- 15% to 40 +/- 13% (p < 0.0001) and 35 +/- 13% (p < 0.0001), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

A case of torsade de pointes occurring in a newborn with persistent 2:1 atrioventricular block

A case of QT interval prolongation with ventricular tachycardia and torsade de pointes is reported. Arrhythmias occurred in a baby with persistent 2:1 atrioventricular block and long QT interval 2 days after birth and were self-limiting. No structural cardiac defect was present. Serum levels of sodium, potassium, magnesium and calcium were in the normal range. Finally, the pathogenetic mechanism of cardiac block is discussed.

New data on the antiarrhythmic value of parenteral magnesium treatment: magnesium and ventricular arrhythmias

Antiarrhythmic magnesium (Mg) therapy was evaluated in 20 normomagnesaemic patients affected by ischaemic dilated cardiomyopathy (ID) and severe ventricular arrhythmias, and in 10 patients with torsade de pointes (TdP) occurring in the setting of acquired QT interval prolongation. In the group with IDC, magnesium sulphate was given as slow infusions (50 mg/min over 60 min) twice a day for 7 d. This was antiarrhythmic in all of the patients: ventricular premature contractions and couplets decreased from 13,979 +/- 8964 (mean +/- SD) to 382 +/- 265 (P < 0.001), and from 516 +/- 274 to 9 +/- 6 (P < 0.001), respectively; runs of ventricular tachycardia (41.9 +/- 14.2) disappeared by the fifth day of treatment. The efficacy of antiarrhythmic treatment was evaluated by 24 h Holter monitoring obtained in baseline conditions and after 3, 5 and 10 d from beginning of therapy. In patients with TdP, Mg infusions were instituted at a slow rate (50 mg/min) and continued for 2 h after disappearance of Tdp, which occurred within 20 to 30 min from the start of the Mg infusions. These were followed by prophylactic infusions at rate of 30 mg/min for 90 min twice a day over the next 3 to 4 d. No side effects were observed, and heart rate and QTc remained unchanged from baseline values. In conclusion, Mg infusions may be an effective antiarrhythmic treatment for short and medium-term control of severe ventricular arrhythmias associated with IDC, and may prove useful in the acute treatment of TdP, especially in situations where conventional therapy might prove deleterious or difficult.