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Premature ventricular contractions (PVCs) are extra, abnormal heartbeats that begin in one of the heart's two lower pumping chambers, or ventricles. They are also called ventricular premature beats (VPBs) and extrasystoles. These extra beats disrupt the regular heart rhythm, which normally starts in the upper right chamber, or atrium. As a result, one may feel a flip-flop or skipped beat in the chest – what is commonly called a palpitation. PVCs are very common and occur in most people from time to time. While they may occur in healthy persons of any age, they are more frequent in the elderly and are more commonly found in men. If patients are otherwise healthy, they may need no specifics treatment for PVCs. However, if there is heart disease, or the palpitations negatively affect quality of life, treatment should be given.

Etiology
Causes of PVCs include:

· ischemia
· certain medicines such as Digoxin, which increases heart contraction
· myocarditis
· cardiomyopathy, hypertrophic or dilated
· myocardial contusion
· myocardial infarction
· hypoxia
· hypercapnia (CO2 poisoning)
· mitral valve prolapse
· smoking tobacco
· alcohol
· certain drugs of abuse, such as cocaine
· caffeine
· some antidepressants
· decreased levels of magnesium and potassium in blood
· increased levels of calcium in blood
· thyroid problems
· chemical (electrolyte) problems in the blood
· increased levels of adrenaline
· lack of sleep/exhaustion
· stress

Diagnosis
In Western medicine, PVCs are usually diagnosed after the patient has described "skipped beats," pauses in the heartbeat, or palpitations. Typically, the palpitations felt by PVC patients are very irregular and less sustained than those in patients with other types of arrhythmia. They are likely to have "flip-flopping" sensations, as if the heart is flipping over or pounding due to a pause after the premature contraction, and then a powerful contraction after the pause. They might also feel a "fluttering" in the chest or a pounding in the neck, but these two types of palpitations are uncommon in PVC patients.

A physical examination is routinely conducted after a full history has been taken. This is useful in determining any possible heart defects that might be causing the palpitations. Most cases of premature ventricular contraction have a mitral valve prolapse, which can be determined through the physical examination. The next step in diagnosis is a 12-lead ECG, a standard type of electrocardiogram, which is usually performed in the doctor's office over a short time. However, this is often nonconclusive in diagnosis, because it is not very sensitive and there is a small chance of a PVC occurring in that short period. Using a Holter monitor, a device that can continuously recording heart rhythm over 24 hours, is a far better method for diagnosis.

When looking at an electrocardiograph, PVCs are easily spotted, and therefore a definitive diagnosis can be made. The QRS and T waves look very different from normal readings. The spacing between the PVC and the preceding QRS wave is much shorter than usual, and the time between the PVC and the proceeding QRS much longer. However, the time between the preceding and proceeding QRS waves stays the same as normal due to the compensatory pause. PVCs can be distinguished from premature atrial contractions, because the compensatory pause is longer following PVCs.

There are five different patterns of PVCs. Bigeminy is when one PVC occurs after every normal beat, in an alternating pattern. Trigeminy is when one PVC occurs after every two normal beats; and quadrigeminy, after every three normal beats. A unifocal PVC is when the depolarization is triggered from the one site in the ventricle. In this case, the peaks on the ECG look the same. Multifocal PVCs arise when more than one site in the ventricles cause depolarization. In that case, each peak on the ECG will have a different shape. If three or more PVCs occur in a row, it indicates ventricular tachycardia, a more serious form of arrhythmia.

Western Medical Treatment
In the Western medical approach, isolated PVCs with benign characteristics require no treatment. In healthy individuals, PVCs can often be resolved with by restoring the balance of magnesium, calcium, and potassium within the body. The most effective treatment is the elimination of triggers (particularly ceasing the abuse of substances such as caffeine and illegal drugs.) Depending on the underlying cause of the PVCs, typical Western medical treatments include:

Pharmacological agents
· beta blockers
· calcium channel blockers

Electrolytes replacement
· magnesium supplements (such as magnesium citrate, magnesium orate, or Maalox)
· potassium supplements

Radio-frequency catheter ablation treatment

Lifestyle modification
· Frequently stressed individuals should consider therapy or joining a support group.
· Heart attacks can increase the likelihood of PVCs. Therefore, exercise and a healthy diet will decrease PVCs by reducing the risk of heart attacks.

In the setting of existing cardiac disease, however, PVCs must be watched carefully, since they may cause a form of ventricular tachycardia.

Chinese Medical Treatment
In Chinese medicine, PVCs correspond to the traditional internal medicine disease categories of xin ji, heart palpitations, and zheng chong, fearful throbbing. Their treatment based on pattern discrimination is discussed in virtually all Chinese internal medicine manuals. However, since most patients present with a combination of these textbook patterns, often the research literature presents a more accurate picture of their Chinese medical treatment. For instance, on pages 710–711 of issue 11, 2008, of Shi Yong Zhong Yi Za Zhi (Journal of Practical Chinese Medicine & Pharmacology), is an article by Wang Tian-peng et al., titled "Clinical Observations on the Treatment of Premature Ventricular Beats with the Combined Use of Chinese & Western Medicine Medicinals." A summary of this article is presented below.

Cohort Description
Altogether, 60 cases of PVC were enrolled in this two-wing comparison study. These cases were randomly divided into two groups of 30 cases each – a treatment group who received both Chinese herbal medicine and Western medicine, and a comparison group who only received the Western medicine. In the treatment group, there were 18 males and 12 females aged 40 to 75 years. In the comparison group, there were 19 males and 11 females aged 38 to 76 years. All these patients met the diagnostic criteria for heart palpitations and a pattern yin vacuity fire effulgence as found in Zhong Yi Bing Zheng Zhen Duan Liao Xiao Biao Zhun (Criteria for Chinese Medical Disease & Pattern Diagnosis and Treatment Efficacy), published by Nanjing University Press in 1995. Patients with myocardial infarction, heart failure, thyroid disease, drug poisoning, electrolyte imbalances, bradycardic arrhythmias, conduction blockage disorders, and supraventricular arrhythmias were excluded from this study. All patients in this study were diagnosed by 24-hour Holter monitor. There were no significant statistical differences in these two groups for the purposes of this study.

Treatment Method
All participants in the treatment group were orally administered the following version of Ning Xin Fang (Calm the Heart Formula):

Xi Yang Shen (Radix Panacis Quinquefolii), 10g
Mai Men Dong (Tuber Ophiopogonis), 15g
mix-fried Huang Qi (Radix Astragali), 10g
Ku Shen (Radix Sophorae), 15g
Huang Lian (Rhizoma Coptidis), 8g
Gua Lou Pi (Pericarpium Trichosanthis), 10g
Dan Shen (Radix Salviae Miltiorrhizae), 30g

One packet of these medicinals was decocted in 300 milliliters of water and administered per day in two divided doses of 150 milliliters each. In addition, all members of the treatment group were administered 150 milligrams T.I.D. of propafenone (Rhythmol). Members of the comparison group only received the same dose of propafenone.

Study Outcomes
"Marked effect" means that the occurrence of PVCs on ECG decreased 90% or more. "Some effect" means that it decreased by 50% or more. "No effect" means that it decreased less than 50%, did not decrease at all, or got worse. The following table shows the outcomes of the two groups based on ECG.

Therefore, the combined use of propafenone and Ning Xin Fang was more effective overall than the use of propafenone alone.

Patients' response to therapy was also judged by a point system having to do with the reduction in their clinical symptoms. The severity of heart palpitations, shortness of breath, lack of strength, insomnia, profuse dreams, dizziness, tinnitus, impaired memory, tidal heat, dry mouth, tongue, and pulse signs were assigned a number from 0 to 6. Zero means the sign or symptom was absent. Two means that it was slight. Four means that it was moderate, and six that it was severe. Patients' symptoms were calculated before and after treatment. The number after treatment was subtracted from the number before treatment. That was then divided by the number before treatment, and the result was multiplied by 100. "Clinical cure" means that the symptoms decreased by 90% or more. "Marked effect" means that they decreased by 70% to 90%. "Some effect" means that they decreased 30% to 70%, and "no effect" means that they decreased by less than 30%. The following table shows these outcomes of the two groups. (As the reader will see, no one was judged clinically cured.)

These results basically parallel the ECG results above. They show that, from a clinical point of view, the combined protocol of integrated Chinese-Western medicine was superior in overall therapeutic effect to the Western drug treatment alone.

Discussion
According to the Chinese authors of this article, heart palpitations and fearful throbbing mostly present as a mixture of vacuity and repletion. The vacuities are of heart qi, blood, yin, and/or yang. Hence the heart spirit loses its nourishment. The repletions are mostly blood stasis, phlegm rheum, and fire depression harassing and causing chaos to the heart spirit. Clinically, one most commonly sees the pattern of yin vacuity fire effulgence, in which case one should boost the qi and nourish yin, clear heat and calm the heart. Within Ning Xin Fang, Xi Yang Shen and Mai Men Dong boost the qi and nourish yin, clear fire and engender fluids. Ku Shen and Huang Lian clear the heart and quiet the spirit. Gua Lou Pi transforms phlegm, loosens the chest, and disinhibits the qi. Dan Shen quickens the blood and dispels stasis, nourishes the blood, quiets the spirit, and calms the heart. When all these medicinals are used together, they support the righteous and dispel evils. Further, according to pharmacologic research, Xi Yang Shen, Huang Qi, Ku Shen, Huang Lian, and Gua Lou Pi all have antiarrhythmic effects.

Although the Chinese authors say the treatment principles for most cases of PVCs should be to boost the qi and nourish yin, clear heat and quiet the spirit, in fact, the formula that they use also treats phlegm dampness and blood stasis. Therefore, it treats all the major factors in heart palpitations and fearful throbbing. This is an example of real-life clinical practice as opposed to beginner's textbook treatment based on (single) pattern discrimination.

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