Flecainide
Encyclopedia
Flecainide acetate is a class Ic antiarrhythmic agent
used to prevent and treat tachyarrhythmias (abnormal fast rhythms of the heart
). It is used to treat a variety of cardiac arrhythmias including paroxysmal atrial fibrillation
(episodic irregular heartbeat originating in the upper chamber of the heart
), paroxysmal supraventricular tachycardia
(episodic rapid but regular heartbeat originating in the atrium), and ventricular tachycardia
(rapid rhythms of the lower chambers of the heart). Flecainide works by regulating the flow of sodium
in the heart, causing prolongation of the cardiac action potential
.
Flecainide was originally sold under the trade name Tambocor (manufactured by 3M pharmaceuticals
). Flecainide went off-patent
on February 10, 2004, and is now available in generic version and under the trade names Almarytm, Apocard, Ecrinal, and Flécaine.
s, including AV nodal re-entrant tachycardia
(AVNRT) and Wolff-Parkinson-White syndrome
(WPW). This is because of the action of flecainide on the His-Purkinje system
.
It also has limited use in the treatment of certain forms of ventricular tachycardia
(VT). In particular, flecainide has been useful in the treatment of ventricular tachycardias that are not in the setting of an acute ischemic event. It has use in the treatment of right ventricular outflow tract (RVOT) tachycardia and in the suppression of arrhythmias in arrhythmogenic right ventricular dysplasia
(ARVD). However, studies have shown an increased mortality when flecainide is used to suppress ventricular extrasystoles
in the setting of acute myocardial infarction.
In individuals suspected of having the Brugada syndrome
, the administration of flecainide may help reveal the ECG findings that are characteristic of the disease process. This may help make the diagnosis of the disease in equivocal cases.
Flecainide has been introduced into the treatment of arrhythmias in the pediatric population.
According to recent research published in Nature Medicine
, flecainide inhibits the release of the cardiac ryanodine receptor–mediated Ca2+, and is therefore believed to medicate the underlying molecular cause of catecholaminergic polymorphic ventricular tachycardia
in both mice and humans.
. Since food digestion can alter the absorption of the drug, Flecainide should be taken one hour before meals.
Given the variable half-life of flecainide and the characteristic QRS prolongation on ECG elicited in flecainide toxicity, especially at rapid heart rates, starting flecainide or changing the level of the drug is done under telemetry monitoring (preferably in a hospital telemetry unit) until a steady state plasma level has been achieved, typically three to five days after the dose has been increased.
For the treatment of supraventricular tachycardia
s and paroxysmal atrial fibrillation
or flutter
in individuals without significant structural heart disease, a starting dose of 50 mg twice a day may be appropriate. The dose may be increased (once a steady state level has been reached) if breakthrough dysrhythmias occur.
For the treatment of life-threatening ventricular arrhythmias (i.e.: ventricular tachycardia
), a starting dose of 100 mg twice a day may be appropriate. As with the treatment of benign arrhythmias, the dose of flecainide given for the treatment of life-threatening ventricular dysrhythmias should not be increased until a steady state has been achieved.
. This thereby slows conduction of the electrical impulse within the heart. The greatest effect is on the His-Purkinje system
and ventricular myocardium. The effect of flecainide on the ventricular myocardium causes decreased contractility of the muscle, which leads to a decrease in the ejection fraction.
The effect of flecainide on the sodium channels of the heart increases as the heart rate increases. This is known as use-dependence. This means that flecainide is potentially more useful to break a tachyarrhythmia (because it has increased effect during the fast heart rate) than to prevent a bradyarrhythmia from occurring (because of its lowered effectiveness during slower heart rates).
after an oral dose, meaning that most of the drug that is ingested will enter the systemic blood stream. Peak serum concentrations can be seen 1 to 6 hours after ingestion of an oral dose. While the plasma half-life
is about 20 hours, it is quite variable, and can range from 12 to 27 hours. During oral loading with flecainide, a steady state equilibrium is typically achieved in 3 to 5 days.
The majority of flecainide is eliminated by the kidney
s, with the remainder metabolized by the cytochrome P450 2D6 isoenzyme
in the liver. Therefore, alterations in renal function or urine pH will greatly affect the elimination of flecainide, as more is eliminated by the hepatic route.
Because of the dual elimination routes of flecainide and its tendency to decrease myocardial contractility
, flecainide interacts with numerous pharmaceuticals and can potentiate the effects of other myocardial depressants and AV node blocking agents. In addition, flecainide can decrease the metabolism or elimination of many (but not all) agents that use the cytochrome P450
enzyme system.
A full list of drug interactions with flecainide can be obtained from the manufacturer. Some important drug interactions with flecainide include:
The dose may need to be adjusted in certain clinical scenarios. As with all other antiarrhythmic agent
s, there is a risk of proarrhythmia
associated with the use of flecainide. This risk is probably increased when flecainide is co-administered with other class Ic antiarrhythmics, such as encainide
. The risk of proarrhythmia may also be increased by hypokalemia
. The risk of proarrhythmia is not necessarily associated with the length of time an individual is taking flecainide, and cases of late proarrhythmia have been reported. Because of the role of both the liver and the kidneys in the elimination of flecainide, the dosing of flecainide may need to be adjusted in individuals who develop either liver failure or renal failure.
Because of the negative inotropic effects of flecainide, it should be used with caution in individuals with depressed ejection fraction
, and may worsen congestive heart failure
in these individuals. It should be avoided in people with ischaemic heart disease and the elderly.
As with all class I antiarrhythmic agents, Flecainide increases the capture thresholds of pacemakers
. Therefore, capture thresholds should be remeasured in individuals with pacemakers after the steady-state flecainide dose is changed.
Signs of flecainide toxicity include marked prolongation of the PR interval and widening of the QRS duration on the surface ECG. There may be signs and symptoms attributable to overt heart failure
secondary to sudden decreased myocardial contractility.
). Placing the individual on cardiopulmonary bypass support may be necessary in order to temporarily obviate the need for a beating heart and to increase blood flow to the liver.
, ischemic heart disease or heart failure.
Antiarrhythmic agent
Antiarrhythmic agents are a group of pharmaceuticals that are used to suppress abnormal rhythms of the heart , such as atrial fibrillation, atrial flutter, ventricular tachycardia, and ventricular fibrillation....
used to prevent and treat tachyarrhythmias (abnormal fast rhythms of the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
). It is used to treat a variety of cardiac arrhythmias including paroxysmal atrial fibrillation
Atrial fibrillation
Atrial fibrillation is the most common cardiac arrhythmia . It is a common cause of irregular heart beat, identified clinically by taking a pulse. Chaotic electrical activity in the two upper chambers of the heart result in the muscle fibrillating , instead of achieving coordinated contraction...
(episodic irregular heartbeat originating in the upper chamber of the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
), paroxysmal supraventricular tachycardia
Supraventricular tachycardia
Supraventricular tachycardia is a general term that refers to any rapid heart rhythm originating above the ventricular tissue. Supraventricular tachycardias can be contrasted to the potentially more dangerous ventricular tachycardias - rapid rhythms that originate within the ventricular...
(episodic rapid but regular heartbeat originating in the atrium), and ventricular tachycardia
Ventricular tachycardia
Ventricular tachycardia is a tachycardia, or fast heart rhythm, that originates in one of the ventricles of the heart...
(rapid rhythms of the lower chambers of the heart). Flecainide works by regulating the flow of sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
in the heart, causing prolongation of the cardiac action potential
Cardiac action potential
In electrocardiography, the cardiac action potential is a specialized action potential in the heart, necessary for the electrical conduction system of the heart....
.
Flecainide was originally sold under the trade name Tambocor (manufactured by 3M pharmaceuticals
3M
3M Company , formerly known as the Minnesota Mining and Manufacturing Company, is an American multinational conglomerate corporation based in Maplewood, Minnesota, United States....
). Flecainide went off-patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
on February 10, 2004, and is now available in generic version and under the trade names Almarytm, Apocard, Ecrinal, and Flécaine.
Uses
Flecainide is used in the treatment of many types of supraventricular tachycardiaSupraventricular tachycardia
Supraventricular tachycardia is a general term that refers to any rapid heart rhythm originating above the ventricular tissue. Supraventricular tachycardias can be contrasted to the potentially more dangerous ventricular tachycardias - rapid rhythms that originate within the ventricular...
s, including AV nodal re-entrant tachycardia
AV nodal reentrant tachycardia
AV nodal reentrant tachycardia , or atrioventricular nodal reentrant tachycardia, is a type of tachycardia of the heart. It is a type of supraventricular tachycardia , meaning that it originates from a location within the heart above the bundle of His. AV nodal reentrant tachycardia is the most...
(AVNRT) and Wolff-Parkinson-White syndrome
Wolff-Parkinson-White syndrome
Wolff–Parkinson–White syndrome is a disorder of the heart in which the ventricles of the heart contract prematurely due to an accessory pathway known as the bundle of Kent. This accessory pathway is an abnormal electrical communication from the atria to the ventricles...
(WPW). This is because of the action of flecainide on the His-Purkinje system
Electrical conduction system of the heart
The normal intrinsic electrical conduction of the heart allows electrical propagation to be transmitted from the Sinoatrial Node through both atria and forward to the Atrioventricular Node. Normal/baseline physiology allows further propagation from the AV node to the ventricle or Purkinje Fibers...
.
It also has limited use in the treatment of certain forms of ventricular tachycardia
Ventricular tachycardia
Ventricular tachycardia is a tachycardia, or fast heart rhythm, that originates in one of the ventricles of the heart...
(VT). In particular, flecainide has been useful in the treatment of ventricular tachycardias that are not in the setting of an acute ischemic event. It has use in the treatment of right ventricular outflow tract (RVOT) tachycardia and in the suppression of arrhythmias in arrhythmogenic right ventricular dysplasia
Arrhythmogenic right ventricular dysplasia
Arrhythmogenic right ventricular dysplasia , also called arrhythmogenic right ventricular cardiomyopathy or arrhythmogenic right ventricular dysplasia/cardiomyopathy , is an inherited heart disease....
(ARVD). However, studies have shown an increased mortality when flecainide is used to suppress ventricular extrasystoles
Premature ventricular contraction
A premature ventricular contraction , also known as a premature ventricular complex, ventricular premature contraction , ventricular premature beat , or extrasystole, is a relatively common event where the heartbeat is initiated by the heart ventricles rather than by the sinoatrial node, the...
in the setting of acute myocardial infarction.
In individuals suspected of having the Brugada syndrome
Brugada syndrome
The Brugada syndrome is a genetic disease that is characterised by abnormal electrocardiogram findings and an increased risk of sudden cardiac death. It is named by the Spanish cardiologists Pedro Brugada and Josep Brugada...
, the administration of flecainide may help reveal the ECG findings that are characteristic of the disease process. This may help make the diagnosis of the disease in equivocal cases.
Flecainide has been introduced into the treatment of arrhythmias in the pediatric population.
According to recent research published in Nature Medicine
Nature Medicine
Nature Medicine is an academic journal publishing research articles, reviews, news and commentaries in the biomedical area, including both basic research and early-phase clinical research. Topics covered include cancer, cardiovascular disease, gene therapy, immunology, vaccines, and neuroscience...
, flecainide inhibits the release of the cardiac ryanodine receptor–mediated Ca2+, and is therefore believed to medicate the underlying molecular cause of catecholaminergic polymorphic ventricular tachycardia
Catecholaminergic polymorphic ventricular tachycardia
Catecholaminergic Polymorphic Ventricular Tachycardia is an electrophysiological disorder of the heart that occurs in genetically predisposed individuals...
in both mice and humans.
Dosing
The dosing of flecainide is varied, with consideration made to the individual's other medications and comorbid conditions and how they may affect the metabolism of flecainide. Individuals with significant renal impairment may require measurement of the plasma level of flecainide to ensure that the drug level remains within the therapeutic range (i.e.: that toxic levels do not occur). In addition, lower drug levels may be sought for the treatment of benign arrhythmias, to lower the chance of inducing a toxic effect of the drug. When used in the pediatric population, the dose of flecainide may be adjusted to the individual's body surface areaBody surface area
In physiology and medicine, the body surface area is the measured or calculated surface of a human body. For many clinical purposes BSA is a better indicator of metabolic mass than body weight because it is less affected by abnormal adipose mass...
. Since food digestion can alter the absorption of the drug, Flecainide should be taken one hour before meals.
Given the variable half-life of flecainide and the characteristic QRS prolongation on ECG elicited in flecainide toxicity, especially at rapid heart rates, starting flecainide or changing the level of the drug is done under telemetry monitoring (preferably in a hospital telemetry unit) until a steady state plasma level has been achieved, typically three to five days after the dose has been increased.
For the treatment of supraventricular tachycardia
Supraventricular tachycardia
Supraventricular tachycardia is a general term that refers to any rapid heart rhythm originating above the ventricular tissue. Supraventricular tachycardias can be contrasted to the potentially more dangerous ventricular tachycardias - rapid rhythms that originate within the ventricular...
s and paroxysmal atrial fibrillation
Atrial fibrillation
Atrial fibrillation is the most common cardiac arrhythmia . It is a common cause of irregular heart beat, identified clinically by taking a pulse. Chaotic electrical activity in the two upper chambers of the heart result in the muscle fibrillating , instead of achieving coordinated contraction...
or flutter
Atrial flutter
Atrial flutter is an abnormal heart rhythm that occurs in the atria of the heart. When it first occurs, it is usually associated with a fast heart rate or tachycardia , and falls into the category of supra-ventricular tachycardias. While this rhythm occurs most often in individuals with...
in individuals without significant structural heart disease, a starting dose of 50 mg twice a day may be appropriate. The dose may be increased (once a steady state level has been reached) if breakthrough dysrhythmias occur.
For the treatment of life-threatening ventricular arrhythmias (i.e.: ventricular tachycardia
Ventricular tachycardia
Ventricular tachycardia is a tachycardia, or fast heart rhythm, that originates in one of the ventricles of the heart...
), a starting dose of 100 mg twice a day may be appropriate. As with the treatment of benign arrhythmias, the dose of flecainide given for the treatment of life-threatening ventricular dysrhythmias should not be increased until a steady state has been achieved.
Mechanism of action
Flecainide works by blocking the Nav1.5 sodium channel in the heart, causing prolongation of the cardiac action potentialCardiac action potential
In electrocardiography, the cardiac action potential is a specialized action potential in the heart, necessary for the electrical conduction system of the heart....
. This thereby slows conduction of the electrical impulse within the heart. The greatest effect is on the His-Purkinje system
Electrical conduction system of the heart
The normal intrinsic electrical conduction of the heart allows electrical propagation to be transmitted from the Sinoatrial Node through both atria and forward to the Atrioventricular Node. Normal/baseline physiology allows further propagation from the AV node to the ventricle or Purkinje Fibers...
and ventricular myocardium. The effect of flecainide on the ventricular myocardium causes decreased contractility of the muscle, which leads to a decrease in the ejection fraction.
The effect of flecainide on the sodium channels of the heart increases as the heart rate increases. This is known as use-dependence. This means that flecainide is potentially more useful to break a tachyarrhythmia (because it has increased effect during the fast heart rate) than to prevent a bradyarrhythmia from occurring (because of its lowered effectiveness during slower heart rates).
Metabolism and drug interactions
Flecainide has high bioavailabilityBioavailability
In pharmacology, bioavailability is a subcategory of absorption and is used to describe the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. By definition, when a medication is administered...
after an oral dose, meaning that most of the drug that is ingested will enter the systemic blood stream. Peak serum concentrations can be seen 1 to 6 hours after ingestion of an oral dose. While the plasma half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
is about 20 hours, it is quite variable, and can range from 12 to 27 hours. During oral loading with flecainide, a steady state equilibrium is typically achieved in 3 to 5 days.
The majority of flecainide is eliminated by the kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s, with the remainder metabolized by the cytochrome P450 2D6 isoenzyme
CYP2D6
Cytochrome P450 2D6 , a member of the cytochrome P450 mixed-function oxidase system, is one of the most important enzymes involved in the metabolism of xenobiotics in the body. Also, many substances are bioactivated by CYP2D6 to form their active compounds...
in the liver. Therefore, alterations in renal function or urine pH will greatly affect the elimination of flecainide, as more is eliminated by the hepatic route.
Because of the dual elimination routes of flecainide and its tendency to decrease myocardial contractility
Ejection fraction
In cardiovascular physiology, ejection fraction is the fraction of Blood pumped out of the Right Ventricle of the heart to the Pulmonary Circulation and Left Ventricle of the heart to the Systemic Circulation with each Heart beat or Cardiac cycle...
, flecainide interacts with numerous pharmaceuticals and can potentiate the effects of other myocardial depressants and AV node blocking agents. In addition, flecainide can decrease the metabolism or elimination of many (but not all) agents that use the cytochrome P450
Cytochrome P450 oxidase
The cytochrome P450 superfamily is a large and diverse group of enzymes. The function of most CYP enzymes is to catalyze the oxidation of organic substances. The substrates of CYP enzymes include metabolic intermediates such as lipids and steroidal hormones, as well as xenobiotic substances...
enzyme system.
A full list of drug interactions with flecainide can be obtained from the manufacturer. Some important drug interactions with flecainide include:
- AlcoholAlcoholIn chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
- may further depress normal heart function. - AmiodaroneAmiodaroneAmiodarone is an antiarrhythmic agent used for various types of tachyarrhythmias , both ventricular and supraventricular arrhythmias. Discovered in 1961, it was not approved for use in the United States until 1985...
- inhibits cytochrome P450 2D6CYP2D6Cytochrome P450 2D6 , a member of the cytochrome P450 mixed-function oxidase system, is one of the most important enzymes involved in the metabolism of xenobiotics in the body. Also, many substances are bioactivated by CYP2D6 to form their active compounds...
and may increase flecainide levels - CimetidineCimetidineCimetidine INN is a histamine H2-receptor antagonist that inhibits the production of acid in the stomach. It is largely used in the treatment of heartburn and peptic ulcers. It is marketed by GlaxoSmithKline under the trade name Tagamet...
- increases flecainide levels by 30% and half-life by 10% - DigoxinDigoxinDigoxin INN , also known as digitalis, is a purified cardiac glycoside and extracted from the foxglove plant, Digitalis lanata. Its corresponding aglycone is digoxigenin, and its acetyl derivative is acetyldigoxin...
- may increase digoxin levels - ParoxetineParoxetineParoxetine is an SSRI antidepressant. Marketing of the drug began in 1992 by the pharmaceutical company SmithKline Beecham, now GlaxoSmithKline...
- increased effect of both drugs. - PropafenonePropafenonePropafenone is a class Ic anti-arrhythmic medication, which treats illnesses associated with rapid heart beats such as atrial and ventricular arrhythmias.-Mechanism of action:...
- increased effect of both drugs and increased risk of toxicity. - QuinidineQuinidineQuinidine is a pharmaceutical agent that acts as a class I antiarrhythmic agent in the heart. It is a stereoisomer of quinine, originally derived from the bark of the cinchona tree.-Mechanism:...
- inhibits cytochrome P450 2D6CYP2D6Cytochrome P450 2D6 , a member of the cytochrome P450 mixed-function oxidase system, is one of the most important enzymes involved in the metabolism of xenobiotics in the body. Also, many substances are bioactivated by CYP2D6 to form their active compounds...
and may increase flecainide levels
Serious adverse reactions
Results of a medical study known as the Cardiac Arrhythmia Suppression Trial (CAST) demonstrated that patients with structural heart disease (such as a history of MI (heart attack), or left ventricular dysfunction) and also patients with ventricular arrhythmias, should not take this drug. The results were so significant that the preliminary results were published. In patients with these kinds of heart diseases, flecainide actually increases the chance of suffering a fatal arrhythmia.The dose may need to be adjusted in certain clinical scenarios. As with all other antiarrhythmic agent
Antiarrhythmic agent
Antiarrhythmic agents are a group of pharmaceuticals that are used to suppress abnormal rhythms of the heart , such as atrial fibrillation, atrial flutter, ventricular tachycardia, and ventricular fibrillation....
s, there is a risk of proarrhythmia
Proarrhythmia
Proarrhythmia is a new or more frequent occurrence of pre-existing arrhythmias, paradoxically precipitated by antiarrhythmic therapy, which means it is a side effect associated with the administration of some existing antiarrhythmic drugs, as well as drugs for other indications...
associated with the use of flecainide. This risk is probably increased when flecainide is co-administered with other class Ic antiarrhythmics, such as encainide
Encainide
Encainide is a class Ic antiarrhythmic agent. It is no longer used because its frequent proarrhythmic side effects....
. The risk of proarrhythmia may also be increased by hypokalemia
Hypokalemia
Hypokalemia or hypokalaemia , also hypopotassemia or hypopotassaemia , refers to the condition in which the concentration of potassium in the blood is low...
. The risk of proarrhythmia is not necessarily associated with the length of time an individual is taking flecainide, and cases of late proarrhythmia have been reported. Because of the role of both the liver and the kidneys in the elimination of flecainide, the dosing of flecainide may need to be adjusted in individuals who develop either liver failure or renal failure.
Because of the negative inotropic effects of flecainide, it should be used with caution in individuals with depressed ejection fraction
Ejection fraction
In cardiovascular physiology, ejection fraction is the fraction of Blood pumped out of the Right Ventricle of the heart to the Pulmonary Circulation and Left Ventricle of the heart to the Systemic Circulation with each Heart beat or Cardiac cycle...
, and may worsen congestive heart failure
Congestive heart failure
Heart failure often called congestive heart failure is generally defined as the inability of the heart to supply sufficient blood flow to meet the needs of the body. Heart failure can cause a number of symptoms including shortness of breath, leg swelling, and exercise intolerance. The condition...
in these individuals. It should be avoided in people with ischaemic heart disease and the elderly.
As with all class I antiarrhythmic agents, Flecainide increases the capture thresholds of pacemakers
Artificial pacemaker
A pacemaker is a medical device that uses electrical impulses, delivered by electrodes contacting the heart muscles, to regulate the beating of the heart...
. Therefore, capture thresholds should be remeasured in individuals with pacemakers after the steady-state flecainide dose is changed.
Toxicity
Due to the narrow therapeutic index of flecainide, physicians should be alert for signs of toxicity before life-threatening arrhythmias occur like torsade de pointes. While the toxic effects of flecainide are closely related to the plasma levels of the drug, it is infeasible to check the plasma concentration in an individual on a regular basis.Signs of flecainide toxicity include marked prolongation of the PR interval and widening of the QRS duration on the surface ECG. There may be signs and symptoms attributable to overt heart failure
Congestive heart failure
Heart failure often called congestive heart failure is generally defined as the inability of the heart to supply sufficient blood flow to meet the needs of the body. Heart failure can cause a number of symptoms including shortness of breath, leg swelling, and exercise intolerance. The condition...
secondary to sudden decreased myocardial contractility.
Treatment
Treatment of flecainide toxicity involves increasing the excretion of flecainide, blocking its effects in the heart, and (rarely) institution of cardiovascular support to avoid impending lethal arrhythmias. Modalities that have had success include administration of a beta-sympathomimetic agent, and administration of a sodium load(often in the form of hypertonic sodium bicarbonateSodium bicarbonate
Sodium bicarbonate or sodium hydrogen carbonate is the chemical compound with the formula Na HCO3. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda . The natural mineral form is...
). Placing the individual on cardiopulmonary bypass support may be necessary in order to temporarily obviate the need for a beating heart and to increase blood flow to the liver.
Long term effects
In the long term, flecainide seems to be safe in patients with a healthy heart with no signs of left ventricular hypertrophyLeft ventricular hypertrophy
Left ventricular hypertrophy is the thickening of the myocardium of the left ventricle of the heart.-Causes:While ventricular hypertrophy occurs naturally as a reaction to aerobic exercise and strength training, it is most frequently referred to as a pathological reaction to cardiovascular...
, ischemic heart disease or heart failure.