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Pharmacologic management of ARVD involves arrhythmia suppression and prevention of thrombus formation.
Sotalol, a beta blocker and a class III antiarrhythmic agent, is the most effective antiarrhythmic agent in ARVD. Other antiarrhythmic agents used include amiodarone and conventional beta blockers (i.e.: metoprolol). If antiarrhythmic agents are used, their efficacy should be guided by series ambulatory holter monitoring, to show a reduction in arrhythmic events.
While angiotensin converting enzyme inhibitors (ACE Inhibitors) are well known for slowing progression in other cardiomyopathies, they have not been proven to be helpful in ARVD.
Individuals with decreased RV ejection fraction with dyskinetic portions of the right ventricle may benefit from long term anticoagulation with warfarin to prevent thrombus formation and subsequent pulmonary embolism.
Recent studies suggest that cardiac resynchronization therapy can reduce the incidence of ventricular dyssynchrony and thus increase cardiac efficiency.
Catheter ablation may be used to treat intractable ventricular tachycardia.
It has a 60–90% success rate. Unfortunately, due to the progressive nature of the disease, recurrence is common (60% recurrence rate), with the creation of new arrhythmogenic foci. Indications for catheter ablation include drug-refractory VT and frequent recurrence of VT after ICD placement, causing frequent discharges of the ICD.
No specific drugs are used to treat pacemaker syndrome directly because treatment consists of upgrading or reprogramming the pacemaker.
Treatment of TIC involves treating both the tachyarrhythmia and the heart failure with the goal of adequate rate control or restoration of the normal heart rhythm (aka. normal sinus rhythm) to reverse the cardiomyopathy. The treatment of the tachyarrhythmia depends on the specific arrhythmia, but possible treatment modalities include rate control, rhythm control with antiarrhythmic agents and cardioversion, radiofrequency (RF) catheter ablation, or AV node ablation with permanent pacemaker implantation.
For TIC due to atrial fibrillation, rate control, rhythm control, and RF catheter ablation can be effective to control the tachyarrhythmia and improve left ventricular systolic function. For TIC due to atrial flutter, rate control is often difficult to achieve, and RF catheter ablation has a relatively high success rate with a low risk of complications. In patients with TIC due to other types of SVT, RF catheter ablation is recommended as a first-line treatment. In patients with TIC due to VT or PVCs, both antiarrhythmics and RF catheter ablation can be used. However, the options for antiarrhythmic agents are limited because certain agents can be proarrhythmic in the setting of myocardial dysfunction in TIC. Therefore, RF catheter ablation is often a safe and effective choice for treatment VT and PVCs causing TIC. In cases where other treatment strategies fail, AV node ablation with permanent pacemaker implantation can also be used to treat the tachyarrhythmia.
The treatment of heart failure commonly involves neurohormonal blockade with beta-blockers and angiotensin convertase inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) along with symptomatic management with diuretics. Beta-blockers and ACE inhibitors can inhibit and potentially reverse the negative cardiac remodeling, which refers to structural changes in the heart, that occurs in TIC. However, the need to continue these agents after treatment of the tacharrhythmia and resolution of left ventricular systolic dysfunction remains controversial.
Isolated PVCs with benign characteristics require no treatment.
In healthy individuals, PVCs can often be resolved by restoring the balance of magnesium, calcium and potassium within the body. In one randomized controlled trial with 60 people those with 260 mg magnesium daily supplementation (in magnesium pidolate) had an average reduction of PVC by 77%. In another trial with 232 persons with frequent ventricular arrhythmias (> 720 PVC/24 h) those with 6 mmol of magnesium (146 mg Mg)/12 mmol of potassium-DL-hydrogenaspartate daily supplementation had median reduction of PVCs by 17%.
The most effective treatment is the elimination of triggers (particularly stopping the use of substances such as caffeine and certain drugs, like tobacco).
- Medications
- Antiarrhythmics: these agents alter the electrophysiologic mechanisms responsible for PVCs. In CAST study of survivors of myocardial infarction encainide and flecainide, although could suppress PVC, they increased death risk; moricizine increased death rate when used with diuretics and decreased it when used alone.
- Beta blockers
- Calcium channel blockers
- Electrolytes replacement
- Magnesium supplements (e.g. magnesium citrate, orotate, Maalox, etc.)
- Potassium supplements (e.g. chloride potassium with citrate ion)
- Radiofrequency catheter ablation treatment. It is advised for people with ventricular dysfunction and frequent arrhythmias or very frequent PVC (>20% in 24 h) and normal ventricular function. This procedure is a way to destroy the area of the heart tissue that is causing the irregular contractions characteristic of PVCs using radio frequency energy.
- Implantable cardioverter-defibrillator
- Lifestyle modification
- Frequently stressed individuals should consider therapy, or joining a support group.
- Heart attacks can increase the likelihood of having PVCs.
In the setting of existing heart disease, however, PVCs must be watched carefully, as they may cause a form of ventricular tachycardia (rapid heartbeat).
The American College of Cardiology and the American Heart Association recommend evaluation for coronary artery disease (CAD) in patients who have frequent PVCs and cardiac risk factors, such as hypertension and smoking (SOR C). Evaluation for CAD may include stress testing, echocardiography, and ambulatory rhythm monitoring.
There are many classes of antiarrhythmic medications, with different mechanisms of action and many different individual drugs within these classes. Although the goal of drug therapy is to prevent arrhythmia, nearly every anti arrhythmic drug has the potential to act as a pro-arrhythmic, and so must be carefully selected and used under medical supervision.
Sometimes surgical intervention is needed. After consulting an electrophysiologist, possibly an additional pacemaker lead placement is needed, which eventually relieve some of the symptoms.
Most SVTs are unpleasant rather than life-threatening, although very fast heart rates can be problematic for those with underlying ischemic heart disease or the elderly. Episodes require treatment when they occur, but interval therapy may also be used to prevent or reduce recurrence. While some treatment modalities can be applied to all SVTs, there are specific therapies available to treat some sub-types. Effective treatment consequently requires knowledge of how and where the arrhythmia is initiated and its mode of spread.
SVTs can be classified by whether the AV node is involved in maintaining the rhythm. If so, slowing conduction through the AV node will terminate it. If not, AV nodal blocking maneuvers will not work, although transient AV block is still useful as it may unmask an underlying abnormal rhythm.
A number of other drugs can be useful in cardiac arrhythmias.
Several groups of drugs slow conduction through the heart, without actually preventing an arrhythmia. These drugs can be used to "rate control" a fast rhythm and make it physically tolerable for the patient.
Some arrhythmias promote blood clotting within the heart, and increase risk of embolus and stroke. Anticoagulant medications such as warfarin and heparins, and anti-platelet drugs such as aspirin can reduce the risk of clotting.
Defibrillation is the definitive treatment of ventricular fibrillation, whereby an electrical current is applied to the ventricular mass either directly or externally through pads or paddles, with the aim of depolarising enough of the myocardium for co-ordinated contractions to occur again. The use of this is often dictated around the world by Advanced Cardiac Life Support or Advanced Life Support algorithms, which is taught to medical practitioners including doctors, nurses and paramedics and also advocates the use of drugs, predominantly epinephrine, after every second unsuccessful attempt at defibrillation, as well as cardiopulmonary resuscitation (CPR) in between defibrillation attempts. Though ALS/ACLS algorithms encourage the use of drugs, they state first and foremost that defibrillation should not be delayed for any other intervention and that adequate cardiopulmonary resuscitation be delivered with minimal interruption.
The precordial thump is a manoeuver promoted as a mechanical alternative to defibrillation. Some advanced life support algorithms advocate its use once and only in the case of witnessed and monitored V-fib arrests as the likelihood of it successfully cardioverting a patient are small and this diminishes quickly in the first minute of onset.
Patients who survive a 'V-fib arrest' and who make a good recovery from this are often considered for implantation of an implantable cardioverter-defibrillator, which can quickly deliver this same life-saving defibrillation should another episode of ventricular fibrillation occur outside a hospital environment.
For those who are stable with a monomorphic waveform the medications procainamide or sotalol may be used and are better than lidocaine. Evidence does not show that amiodarone is better than procainamide.
As a low magnesium level in the blood is a common cause of VT, magnesium sulfate can be given for torsades de pointes or if a low blood magnesium level is found/suspected.
Long-term anti-arrhythmic therapy may be indicated to prevent recurrence of VT. Beta-blockers and a number of class III anti-arrhythmics are commonly used, such as the beta-blockers carvedilol, metoprolol, and bisoprolol, and the Potassium-Channel-Blockers amiodarone, dronedarone,bretylium, sotalol, ibutilide, and dofetilide. Angiotensin-converting-eynsyme (ACE) inhibitors and aldostrone antatagonists are also sometimes used in this setting.
Medications to treat CPVT include beta blockers and verapamil.
Flecainide inhibits the release of the cardiac ryanodine receptor–mediated Ca, and is therefore believed to medicate the underlying molecular cause of CPVT in both mice and humans.
Once an acute arrhythmia has been terminated, ongoing treatment may be indicated to prevent recurrence. However, those that have an isolated episode, or infrequent and minimally symptomatic episodes, usually do not warrant any treatment other than observation.
In general, patients with more frequent or disabling symptoms warrant some form of prevention. A variety of drugs including simple AV nodal blocking agents such as beta-blockers and verapamil, as well as anti-arrhythmics may be used, usually with good effect, although the risks of these therapies need to be weighed against potential benefits.
Radiofrequency ablation has revolutionized the treatment of tachycardia caused by a re-entrant pathway. This is a low-risk procedure that uses a catheter inside the heart to deliver radio frequency energy to locate and destroy the abnormal electrical pathways. Ablation has been shown to be highly effective: around 90% in the case of AVNRT. Similar high rates of success are achieved with AVRT and typical atrial flutter.
Cryoablation is a newer treatment for SVT involving the AV node directly. SVT involving the AV node is often a contraindication for using radiofrequency ablation due to the small (1%) incidence of injuring the AV node, requiring a permanent pacemaker. Cryoablation uses a catheter supercooled by nitrous oxide gas freezing the tissue to −10 °C. This provides the same result as radiofrequency ablation but does not carry the same risk. If you freeze the tissue and then realize you are in a dangerous spot, you can halt freezing the tissue and allow the tissue to spontaneously rewarm and the tissue is the same as if you never touched it. If after freezing the tissue to −10 °C you get the desired result, then you freeze the tissue down to a temperature of −73 °C and you permanently ablate the tissue.
This therapy has further improved the treatment options for people with AVNRT (and other SVTs with pathways close to the AV node), widening the application of curative ablation to young patients with relatively mild but still troublesome symptoms who would not have accepted the risk of requiring a pacemaker.
Implantable cardioverter-defibrillators are used to prevent sudden death.
A person with pulseless VT is treated the same as ventricular fibrillation with high-energy (360J with a monophasic defibrillator, or 200J with a biphasic defibrillator) unsynchronised cardioversion (defibrillation). They will be unconscious.
The shock may be delivered to the outside of the chest using the two pads of an external defibrillator, or internally to the heart by an implantable cardioverter-defibrillator (ICD) if one has previously been inserted.
An ICD may also be set to attempt to overdrive pace the ventricle. Pacing the ventricle at a rate faster than the underlying tachycardia can sometimes be effective in terminating the rhythm. If this fails after a short trial, the ICD will usually stop pacing, charge up and deliver a defibrillation grade shock.
Current treatment options for Boxer cardiomyopathy are largely restricted to the use of oral anti-arrhythmic medications. The aim of therapy is to minimize ventricular ectopy, eliminate syncopal episodes, and prevent sudden cardiac death. A number of medications have been used for this purpose, including atenolol, procainamide, sotalol, mexiletine, and amiodarone. Combinations can also be used. Sotalol is probably the most commonly used antiarrhythmic at this time. It has been demonstrated that sotalol alone, or a combination of mexiletine and atenolol, results in a reduction in the frequency and complexity of ventricular ectopy. It is likely that these medications also reduce syncopal episodes, and it is hoped this extends to a reduced risk of sudden death. Consequently, antiarrhythmic therapy is typically recommended by veterinary cardiologists for Boxer dogs with ARVC. Although relatively rare, oral antiarrhythmic medications may be proarrhythmic in some dogs; consequently, appropriate monitoring and follow-up is recommended.
The ideal therapy for Boxer cardiomyopathy would be implantation of an implantable cardioverter-defibrillator (ICD). This has been attempted in a limited number of dogs. Unfortunately, ICDs are programmed for humans and the algorithms used are not appropriate for dogs, increasing the risk of inappropriate shocks. In the future, reprogramming of ICDs may allow them to emerge as a viable option in the treatment for Boxer cardiomyopathy.
In people without underlying heart disease and who do not have any symptoms, bigeminy in itself does not require any treatment. If it does become symptomatic, beta-blockers can be used to try and suppress ventricular ectopy. Class I and III agents are generally avoided as they can provoke more serious arrhythmias.
Generally, diastolic dysfunction is a chronic process. When this chronic condition is well tolerated by an individual, no specific treatment may be indicated. Rather, therapy should be directed at the root cause of the stiff left ventricle, with potential causes and aggravating factors like high blood pressure and diabetes treated appropriately. Conversely (as noted above), diastolic dysfunction tends to be better tolerated if the atrium is able to pump blood into the ventricles in a coordinated fashion. This does not occur in atrial fibrillation (AF), where there is no coordinated atrial activity and the left ventricle loses around 20% of its output. However, in chronic AF and in geriatric patients, AF is better tolerated and the cardiologist must choose between a stable AF at a lower rate and the risk of having an intermittent AF if he pretends to treat AF aggressively with all the thrombo-embolic risk it implies. In the same light, and also as noted above, if the atrial fibrillation persists and is resulting in a rapid heart rate, treatment must be given to slow down that rate. Usually digoxin maintains a stable rhythm. The use of a self-expanding device that attaches to the external surface of the left ventricle has been suggested, yet still awaits FDA approval. When the heart muscle squeezes, energy is loaded into the device, which absorbs the energy and releases it to the left ventricle in the diastolic phase. This helps retain muscle elasticity.
The role of specific treatments for diastolic dysfunction "per se" is as yet unclear. Diuretics can be useful, if these patients develop significant congestion, but patients must be monitored because they frequently develop hypotension.
Beta-blockers are the first-line therapy as they induce bradycardia and give time for ventricles to fill. There is some evidence that calcium channel blocker drugs may be of benefit in reducing ventricular stiffness in some cases (verapamil has the benefit lowering the heart rate). Likewise, treatment with angiotensin converting enzyme inhibitors, such as enalapril, ramipril, and many others, may be of benefit due to their effect on preventing ventricular remodeling but under control to avoid hypotension.
The primary goal of medications is to relieve symptoms such as chest pain, shortness of breath, and palpitations. Beta blockers are considered first-line agents, as they can slow down the heart rate and decrease the likelihood of ectopic beats. For people who cannot tolerate beta blockers, nondihydropyridine calcium channel blockers such as verapamil can be used, but are potentially harmful in people who also have low blood pressure or severe shortness of breath at rest. These medications also decrease the heart rate, though their use in people with severe outflow obstruction, elevated pulmonary artery wedge pressure, and low blood pressures should be done with caution. Dihydropyridine calcium channel blockers should be avoided in people with evidence of obstruction. For people whose symptoms are not relieved by the above treatments, disopyramide can be considered for further symptom relief. Diuretics can be considered for people with evidence of fluid overload, though cautiously used in those with evidence of obstruction. People who continue to have symptoms despite drug therapy can consider more invasive therapies. Intravenous phenylephrine (or another pure vasoconstricting agent) can be used in the acute setting of low blood pressure in those with obstructive hypertrophic cardiomyopathy who do not respond to fluid administration.
The prognosis for TIC after treatment of the underlying tachyarrhythmia is generally good. Studies show that left ventricular function often improves within 1 month of treatment of the tachyarrhythmia, and normalization of the left ventricular ejection fraction occurs in the majority of patients by 3 to 4 months. In some patients however, recovery of this function can take greater than 1 year or be incomplete. In addition, despite improvement in the left ventricular ejection fraction, studies have demonstrated that patients with prior TIC continue to demonstrate signs of negative cardiac remodeling including increased left ventricular end-systolic dimension, end-systolic volume, and end-diastolic volume. Additionally, recurrence of the tachyarrhythmia in patients with a history of TIC has been associated with a rapid decline in left ventricular ejection fraction and more severe cardiomyopathy that their prior presentation, which may be a result of the negative cardiac remodeling. There have also been cases of sudden death in patients with a history of TIC, which may be associated with worse baseline left ventricular dysfunction. Given these risks, routine monitoring with clinic visits, ECG, and echocardiography is recommended.
For patients in acute heart failure, ACE inhibitors, angiotensin receptor blockers, and beta blockers, are considered mainstays of heart failure treatment. But use of beta blockers specifically for takotsubo cardiomyopathy is controversial, because they may confer no benefit.
As previously stated, management of HFpEF is primarily dependent on the treatment of symptoms and exacerbating conditions. Currently treatment with ACE inhibitors, calcium channel blockers, beta blockers, and angiotensin receptor blockers are employed but do not have a proven benefit in HFpEF patients. Additionally, use of Diuretics or other therapies that can alter loading conditions or blood pressure should be used with caution. It is not recommended that patients be treated with phosphodiesterase-5-inhibitors or digoxin.
Antimineralocorticoid is currently recommended for patients with HFpEF who show elevated brain natriuretic peptide levels. Spironolactone is the first member of this drug class and the most frequently employed. Care should be taken to monitor serum potassium levels as well as kidney function, specifically glomerular filtration rate during treatment.
Beta blockers play a rather obscure role in HFpEF treatment but appear to play a beneficial role in patient management. There is currently a deficit of clinical evidence to support a particular benefit for HFpEF patients, with most evidence resulting from HFpEF patients' inclusion in broader heart failure trials. However, some evidence suggests that vasodilating beta blockers, such as nebivolol, can provide a benefit for patients with heart failure regardless of ejection fraction. Additionally, because of the chronotropic perturbation and diminished LV filling seen in HFpEF the bradycardic effect of beta blockers may enable improved filling, reduced myocardial oxygen demand and lowered blood pressure. However, this effect also can contribute to diminished response to exercise demands and can result in an excessive reduction in heart rate.
ACE inhibitors do not appear to improve morbidity or mortality associated with HFpEF alone. However, they are important in the management of hypertension, a significant player in the pathophysiology of HFpEF.
Angiotensin II receptor blocker treatment shows an improvement in diastolic dysfunction and hypertension that is comparable to other anti-hypertensive medication.
Despite increasing incidence of HFpEF effective inroads to therapeutics have been largely unsuccessful. Currently, recommendations for treatment are directed at symptom relief and co-morbid conditions. Frequently this involves administration of diuretics to relieve complications associated with volume overload, such as leg swelling and high blood pressure.
Commonly encountered conditions that must be treated for and have independent recommendations for standard of care include atrial fibrillation, coronary artery disease, hypertension, and hyperlipidemia. There are particular factors unique to HFpEF that must be accounted for with therapy. Unfortunately, currently available randomized clinical trials addressing the therapeutic adventure for these conditions in HFpEF present conflicting or limited evidence.
Specific aspects of therapeutics should be avoided in HFpEF to prevent the deterioration of the condition. Considerations that are generalizable to heart failure include avoidance of a fast heart rate, elevations in blood pressure, development of ischemia, and atrial fibrillation. More specific to HFpEF include avoidance of preload reduction. As patients display normal ejection fraction but reduced cardiac output they are especially sensitive to changes in preloading and may rapidly display signs of output failure. This means administration of diuretics and vasodilators must be monitored carefully.
HFrEF and HFpEF represent distinct entities in terms of development and effective therapeutic management. Specifically cardiac resynchronization, administration of beta blockers and angiotensin converting enzyme inhibitors are applied to good effect in HFrEF but are largely ineffective at reducing morbidity and mortality in HFpEF. Many of these therapies are effective in reducing the extent of cardiac dilation and increasing ejection fraction in HFrEF patients. It is unsurprising they fail to effect improvement in HFpEF patients, given their un-dilated phenotype and relative normal ejection fraction. Understanding and targeting mechanisms unique to HFpEF are thus essential to the development of therapeutics.
Randomized studies on HFpEF patients have shown that exercise improves left ventricular diastolic function, the heart's ability to relax, and is associated with improved aerobic exercise capacity. The benefit patients seem to derive from exercise does not seem to be a direct cardiac effect but rather is due to changes in peripheral vasculature and skeletal muscle, which show abnormalities in HFpEF patients.
Patients should be regularly assessed to determine progression of the condition, response to interventions, and need for alteration of therapy. Ability to perform daily tasks, hemodynamic status, kidney function, electrolyte balance, and serum natriuretic peptide levels are important parameters. Behavioral management is important in these patients and it is recommended that individuals with HFpEF avoid alcohol, smoking, and high sodium intake.
For people with cardiogenic shock, medical treatment is based on whether a left ventricular outflow tract (LVOT) obstruction is present. Therefore, early echocardiography is necessary to determine proper management. For those with obstructed LVOTs inotropic agents should not be used, but instead should be managed like patients with hypertrophic cardiomyopathy, (e.g. phenylephrine and fluid resuscitation). For cases in which the LVOT is not obstructed, inotropic therapy (e.g. dobutamine and dopamine) may be used, but with the consideration that takotsubo is caused by excess catecholamines.
Furthermore, mechanical support with an intra-aortic balloon pump (IABP) is well-established as supportive treatment.