The Use of Convallaria and Crataegus in the Treatment of Cardiac Dysfunction

There are effective herbal remedies to treat cardiac dysfunctions (e.g., arrythmias) that may complement or replace standard pharmaceutical options. In the 20^th century, researchers have demonstrated that some herbal remedies not only improve cardiac health, but may even decrease the symptoms of cardiac dysfunction such that medications may be unnecessary (or the dosages reduced). Herbs used by Complementary Alternative Medicine (CAM) practitioners (such as Convallaria and Crataegus) are generally considered safe supplements. Modern clinical research suggests a significant benefit in symptom control and physiologic outcomes when Crataegus is used as an adjunctive treatment in patients with chronic heart failure.

Convallaria and Crataegus have been used for centuries by herbalists in the treatment of certain cardiac dysfunctions. Convallaria has been used for congestive heart failure and cardiomyopathy, while Crataegus has been used as an all-purpose cardiac and vascular tonic.

Positive ionotropic effects may also be accomplished with Crataegus and some other herbs. In these plants, the primary mechanism involves cyclic AMP (adenosine monophosphate). When stimulated, receptors on the outsides of muscle cell membrane enable the synthesis of adenylyl cyclase, the enzyme that catalyzes the production of intracellular cAMP. The presence of cAMP activates the calcium channels in the muscle cell membranes. In heart muscle cells, calcium influx promotes increased heart contractility. When epinephrine and norepinephrine bind to membrane receptors, a chain reaction is initiated; the increased calcium level results in increased ionotropic capacity.

Crataegus (Hawthorne Tree) species are actually several varieties of the Hawthorne tree, and it was used in early European medicine for a wide variety of cardiac and vascular conditions. As this tree (in the rose family) flowers in Europe in May, it became commonly known as the “Mayflower”.

Crataegus does not contain cardiac glycosides, but rather a group of flavonoids. These flavonoids have anti-inflammatory, anti-oxidant, and protective cardiac effects. The berries and other constituents present in the buds of the flowers have particularly positive effects. Crataegus contains large amounts of flavonoid anthocyanidins and proanthocyanidins, as well as condensed polyphenolic tannins known as procyanidolic oligomers (PCOs). The flavonoids have a stabilizing effect on capillaries, and serve to reduce vascular permeability and fragility. Crataegus extracts (and particularly their flavonoids) may support cardiac mitochondrial respiration.

Crataegus flower buds contain quercitin, other anti-inflammatory flavonoids, and volatile amines. Hawthorne berries also contain sugar, pectin, Vitamin C, and glycosides. The leaves contain catechins and traces of sterols. Chemically, these procyanidins (such as 1-epicatechol) are small dimers of epicatechin (a tannin derivative). Other flavonoids found in Crataegus include vitexin-4-rhamnoside, rutin, and quercitin. Other constituents include ursolic, oleanic, and cinnamic organic acids, along with sterols, purines, triterpenes, and cardiotonic amines including trimethylamine, isobutylamine, and tyramine. Currently, many Crataegus supplements are standardized to 10-28% PCO content.

The procyanidins found in Crataegus also inhibit phosphodiasterase, the enzyme that degrades cAMP into inactive AMP. Since the breakdown of cAMP is prevented by Crataegus, calcium levels remain high; this leads to sustained myocardial contractility. While elevations in cAMP and intracellular calcium promote contractions of coronary muscle, the same conditions promote relaxation of blood vessel smooth muscle. Thus, blood flow through the heart is not impaired due to vasoconstriction. Crataegus enhances myocardial contractility, yet coronary arteries are dilated rather than contracted.

Extracts of Crataegus leaf, flower, and berry have been shown to promote calcium influx via effects on sodium and potassium ATPase mechanisms,and to promote calcium concentrations affecting myocontractility.

Crataegus constituents act as natural angiotensin converting enzyme (ACE) inhibitors. ACE is an important enzyme involved with blood pressure regulation and also sodium and electrolyte balance in tissues. Inhibiting ACE also serves to lower blood pressure and strengthen heart muscle function. Crataegus inhibits ACE, presumably due to its procyanidin oligomers. When this enzyme is inhibited, angiotensin I is not converted to angiotensin II. As a result, the production of aldosterone is reduced. Since aldosterone promotes water and sodium retention, sodium and water (in the absence of aldosterone) are more easily excreted. Additionally, angiotensin II promotes vasconstriction and inactivates bradykinin—a polypeptide with vasodilating action. When ACE is inhibited, bradykinin promotes the release of other vasodilatory prostaglandins which, in turn, improve blood flow and oxygen delivery to the heart muscle. (Fig 1)

Crataegus has long been used as a heart tonic for both hyper- and hypotension. Researchers have demonstrated that Crataegus may also be helpful in treating elevated cholesterol levels, high blood pressure, angina pectoris, and atherosclerosis.Crataegus may also regulate heart rhythm in patients with heart failure. There have been clinical trials using Crataegus extracts in patients with Congestive Heart Failure (CHF) showing significant improvements in symptoms. In animal models, studies have shown Crataegus to improve aortic contractility in heart failure.

Studies on the use of Crataegus along with standard pharmaceutical treatments for heart failure have not revealed any negative drug-herb interactions, and have suggested that Crataegus may slow the progression of heart failure. One study reported that the addition of Crataegus to the overall protocol for heart failure patients reduced the incidence of sudden cardiac death.

In cardiomyopathy, the heart muscle progressively weakens and becomes increasingly ineffective at pumping blood. Typical chronical management is with chemical pharmaceuticals, and the only definitive cure is by heart transplant. Many medications used to treat cardiomyopathy have stemmed fromDigitalis and its cardiac glycosides (e.g., digoxin and digitalin).

Cardiac glycosides (steroid-like molecules that act on cardiac smooth muscle) are sometimes termed “positive ionotropic agents” because they positively affect the flow of ions across cardiac muscle cell membranes. Muscle cells (including cardiac muscle cells) need to be able to contract and expand—and it is the flow of charged calcium, potassium and other ions across the cell membrane that serves to establish electrical currents, enabling depolarization and repolarization.

Convallaria majallus (Lily of the Valley) contains cardiac glycosides. For centuries, many herbalists and medical practitioners considered Convallaria majallus to be safer than Digitalis. For centuries, herbalists have considered the roots of the Convallaria plant to be a treatment for a weak heart, shortness of breath tachycardia and arrythmia. Convallaria majalis contains at least around 40 cardiac glycosides (including convallarin, convallotoxin, convalloside, convallasaponin, cholestane glycoside, strophanthidin, cannogenol, sarmentogenin, dipindogenin and hydroxysarmentogenin).

The Convallaria plant transforms convalloside (the basic metabolic glycoside) into convallatoxin and other cardiac glycosides. Convallatoxin affects vasoconstriction and vasodilation, and cardiac stroke volume, pulse pressure and cAMP activity are all enhanced by Convallaria.Convallamaroside may reduce angiogenesis and have anti-tumor effects.Convallaria has also been shown to be a lipoxygenase inhibitor.

These herbs described hererin may be used alone or in combination to support heart function. A 2008 meta-analysis on a Crataegus clinical trial reported no adverse advents, and the only significant side effects to be mild and transient. Studies have shown Crataegus to be safe when used in tandem with conventional pharmaceutical therapies in the management of congestive heart failure and other cardiac maladies. The use of Convallaria and Crataegus are both medicinal herbs that in appropriate doses can be used safely and effectively to manage basic cardiac dyfunction.

Dr. Saunders reports personal fees related to employment or seeing patients from CCNM, the Dundas Naturopathic Centre, and from Beaumont Health Systems, Troy Hospital, MI, outside the submitted work. Dr. Winston reports personal fees from Herbalist & Alchemist, Inc, outside the submitted work. Dr. Stansbury and Dr. Zampieron have nothing to disclose.