Worsening of vasovagal syncope after beta-blocker therapy

Islamic fasting: cardiovascular disease perspective

INTRODUCTION

Ramadan is a month of obligatory fasting observed by the majority of 2 billion Muslims living around the globe. The guidelines for 'risk-free' fasting exist for chronic diseases, including diabetes mellitus, but recommendations for cardiovascular disease (CVD) patients are deficient due to the paucity of literature.

AREAS COVERED

Databases were screened to find relevant studies for an evidence-based consensus regarding the risk stratification and management of CVD. Using practical guidelines of the European Society of Cardiology (ESC), we categorized patients into low-, moderate-, and high-risk categories and proposed a pre-Ramadan checklist for the assessment of cardiac patients before fasting. Regular moderate-intensity exercise is recommended for most cardiac patients, which has been demonstrated to provide an anti-inflammatory and antioxidant effect that improves immune function.

EXPERT OPINION

In Ramadan, many physiological changes occur during fasting, which brings about a balanced metabolic homeostasis of the body. In addition, Ramadan fasting is a nonpharmacologic means of decreasing CV risk factors. As Islam exempts Muslims from fasting if they are unwell; therefore, patients with the acute coronary syndrome (ACS), advanced heart failure (HF), recent percutaneous coronary intervention (PCI), or cardiac surgery should avoid fasting.

A review of pathophysiology and therapy of patients with vasovagal syncope

Vasovagal syncope is a common disorder that can compromise quality of life and lead to significant morbidity. It is characterized by an initial exaggerated sympathetic output followed by parasympathetic activation and sympathetic withdrawal, as shown by diagnostic head-up tilt (HUT) table testing. Numerous drugs have been evaluated for treating this disorder. beta-Blockers are well studied and commonly administered but are specifically more efficacious in patients with isoproterenol HUT than in those with regular HUT. The role of the serotonergic system has captured new interest. Selective serotonin reuptake inhibitors show promising results in preventing vasovagal syncope in treatment-refractory patients. Also, new investigations suggest that serotonin receptor antagonism may be beneficial. Despite these findings, definitive treatment does not exist.

Efficacy and safety of clonazepam in refractory neurally mediated syncope

Neurally mediated syncope is a complex syndrome that is often difficult to manage using currently available treatment strategies. The efficacy and safety of clonazepam was evaluated in 35 patients with refractory neurally mediated syncope. All patients had syncope (n = 33) or disabling presyncope (n = 2) and a positive head-up tilt table test (HUTT) despite treatment with one or more of the following therapies: beta-blocker, high-salt diet, fludrocortisone, elastic compression stockings, and disopyramide. Clonazepam was initiated at 0.5 mg/day and titrated in 0.25-0.5 mg/day increments for symptom control. Early (first 8 weeks) symptomatic response was achieved in 31 of 35 (89%) patients. Early HUTT reverted to negative in 29 of 35 (83%) patients. Two patients discontinued clonazepam during early follow-up due to side effects. Thirty-three patients received long-term clonazepam therapy. Twenty-five patients had late HUTT with 21 remaining negative. Of the eight patients who did not have late HUTT, one patient discontinued clonazepam prior to HUTT due to side effects. Seven patients refused late HUTT. All seven patients achieved symptomatic control on clonazepam with two requiring dose titration. Of the 21 patients with a negative late HUTT, 18 achieved symptomatic control with two of these patients requiring dose titration. Two patients who had only partial symptom control despite dose titration achieved total symptomatic control with the addition of disopyramide and beta-blockers. Two patients with a negative late HUTT discontinued clonazepam due to side effects. One patient had been symptomatically controlled while the other had recurrent symptoms with dose limiting side effects occurring after clonazepam dose titration. In the 4 patients with a positive late HUTT, 2 patients were symptomatically controlled, 1 patients required combination therapy with a beta-blocker to achieve symptomatic control, and 1 patient discontinued therapy due to side effects. Overall, 29 of 35 (83%) patients continue to receive clonazepam with symptom control. Based on intention-to-treat HUTT results, 21 of 35 (60%) patients were responders. Four patients required clonazepam dose titration and three required combination therapy with clonazepam plus disopyramide and/or a beta-blocker to achieve control. Clonazepam was discontinued in 6 patients, 5 for side effects and 1 following a transient ischemic attack. Clonazepam appears to be an effective therapeutic alternative in patients with refractory neurally mediated syncope. Based on our preliminary findings, a placebo controlled evaluation of clonazepam in neurally mediated syncope is warranted.

Syncope: pathophysiology, diagnosis, and pharmacotherapy

OBJECTIVE

To review the pathophysiology, diagnosis, and pharmacotherapy of syncope, with emphasis placed on neurocardiogenic syncope.

DATA SOURCES

A MEDLINE search (1980-1995) using the term syncope and cross-referencing selected articles.

STUDY SELECTION

Articles selected were those considered to assist in providing the reader with a basic introduction the pathophysiology, diagnosis, and pharmacotherapy of syncope, with emphasis placed on neurocardiogenic syncope.

DATA SYNTHESIS

Syncope is a common disorder with many different etiologies. The patient's history and physical examination are extremely important in making the diagnosis. The recent availability of head-upright tilt testing and electrophysiologic studies of the myocardium have helped define the etiology in many patients in whom an etiology would not have been found in the past. When the cause of syncope has been diagnosed, the appropriate therapy to prevent future attacks will be defined in many instances. One form of syncope, known as neurocardiogenic syncope, can be difficult to treat. Recent trials have suggests the use of beta-blockers, fludrocortisone, disopyramide, or selective serotonin reuptake inhibitors may be helpful in some patients.