Catheter ablation for ventricular tachycardia (VT) in patients with ischemic heart disease: a systematic review and a meta-analysis of randomized controlled trials


Abstract

Background

Patients with ischemic heart disease may have implantable cardioverter defibrillators (ICDs) implanted for primary or secondary prevention of sudden cardiac death. Although ICD shocks can be life saving, in some patients, they have been associated with increased mortality and/or morbidity. Several studies have suggested that catheter ablation may be superior to non-ablative strategies at preventing ICD shocks delivered for ventricular arrhythmias; however, this is still controversial.

Methods

We performed a meta-analysis of randomized controlled trials (RCTs) comparing catheter ablation with non-ablative strategies in treatment of ventricular tachycardia (VT) in patients with ischemic heart disease and an ICD. The primary endpoints of interest were recurrent episodes of VT and death. We used a binary random effects method to calculate the cumulative odds ratios (OR) for recurrent VT and deaths.

Results

Of a total of 643 potential citations, our search yielded three citations that met our inclusion and exclusion criteria. In the three trials, a total of 262 patients were randomized to ablation (n = 129) or non-ablative interventions (beta-blockers ± use of antiarrhythmics) (n = 133) group. The cumulative OR for recurrent VT was 0.471 (95 % confidence interval (CI) = 0.176–1.257) for catheter ablation compared with non-ablative strategies, and for death, it was 0.766 (95 % CI = 0.351–1.674). Excluding one study for being appreciably smaller than the other two, the OR for recurrent VT was 0.298 (95 % CI = 0.164–0.543).

Conclusions

In this meta-analysis, the rate of recurrent VT was lower with VT catheter ablation compared with non-ablative strategies. There was not a significant difference in rate of death among patients receiving catheter ablation versus non-ablative strategies for management of VT. Given the lack of adequately powered RCTs comparing ablation versus medical management of VT in patients with ischemic heart disease and an ICD, larger studies with longer follow-up are needed.

Keywords

Breast Cancer, Radiation Therapy, and Ischemic Heart Disease


image

Breast cancer is the leading cause of cancer deaths in women in the U.S. Survival is better when breast cancer is diagnosed while still local, and 60.8% of women in the U.S. are diagnosed at this stage. In this group of patients, 5-year survival is 98.5%, according to data from the Surveillance, Epidemiology, and End Results (SEER) Program.1 In these cases, surgical treatment with lumpectomy or mastectomy is often followed by radiation therapy.

In fact, a recent meta-analysis of 22 randomized trials provided additional support for the use of postmastectomy radiation in decreasing the rate of mortality related to recurrent cancer and breast cancer in women found to have 1 to 3 positive lymph nodes during mastectomy and axillary dissection.2 As a result of this and other studies, the need to understand the long-term effects of radiation therapy has become more urgent. One of the most important questions is: Does radiotherapy to the chest increase the incidence of ischemic heart disease (IHD)?

The dose of radiation to the breast and heart is now considerably lower than it has been in the past.3 Nonetheless, when malignancies of the right breast are treated with radiation, the heart is typically exposed to a dose of approximately 1 to 2 Gy. Heart exposure is higher for disease of the left breast, of course, and may run up to 10 Gy.4

A recent study assessed how the dose of radiation a woman receives during breast cancer treatment affects her subsequent risk of IHD.

Darby and colleagues performed a case-control study of major coronary events in women who received external beam radiotherapy for invasive breast cancer.4 Major coronary events were defined as myocardial infarction, coronary revascularization, and death from IHD. Their study, recently published in the New England Journal of Medicine (NEJM), included 2168 women who received radiotherapy for breast cancer from 1958 to 2001 in Sweden and Denmark. Of these, 963 women had major coronary events, and 1205 did not and served as controls. Radiation doses to the whole heart and to the left anterior descending artery were estimated based on radiotherapy records.

Mean radiation dose to the heart was 4.9 Gy (range, 0.03 to 27.72). The rate of cardiovascular events increased by 7.4% for each increment of 1 Gy (95% CI, 2.9 to 14.5;P<.001), with no threshold below which there was no risk. This deleterious effect on the heart started within the first 5 years after therapy and continued for at least 20 years. The presence of cardiac risk factors increased the absolute rate of cardiac outcomes but didn’t affect the proportional increase in the rate of major coronary events per Gy.

None of the women in the study received the cardiotoxic chemotherapeutic agents taxanes or trastuzumab, and very few received anthracyclines, thus minimizing these confounders for ischemic outcomes.

Though radiation delivery techniques have improved considerably in recent decades, the incidental exposure of radiation to the heart is always of concern, and strategies to minimize radiation should be exercised whenever possible. Despite this, as Fei-Fei Liu, MD, Professor of Radiation Oncology at the University of Toronto, stated in an editorial that accompanied the Darby article, “It is important to reassure women with breast cancer that with the use of current technologies, the cardiac dose can be decreased considerably, and cardiac risk factors can be better managed.”

Investigator Sarah C. Darby, PhD, of the Clinical Trial Service Unit at the University of Oxford, England, says that “One thing that our studies have shown rather clearly is that any radiation-related risk probably multiplies the risk that a woman already has. Therefore, women who are already at increased risk of heart disease are likely to be at the greatest risk.”

Dr. Darby and her colleagues provided an example of this in the NEJM article:

  • In a 50-year-old woman with no cardiac risk factors at baseline, a 3-Gy dose of radiation to the heart would increase her risk of fatal IHD at age 80 from 1.9% to 2.4% (0.5 percentage points) and her risk of having at least 1 acute coronary event from 4.5% to 5.4% (0.9 percentage points).
  • In a 50-year-old woman with at least 1 cardiac risk factor, a 3-Gy dose of radiation would increase her risk of fatal IHD at age 80 from 3.4% to 4.1% (0.7 percentage points) and her risk of having at least 1 acute coronary event by then by 1.7 percentage points.

In their conclusions, Dr. Darby’s team wrote that because the percentage increase in IHD risk per unit increase in the mean radiation dose to the heart was similar in women with and without cardiac risk factors, one could assume that absolute risk increase at a specific dose was larger for women with preexisting cardiac risk factors.

“Therefore, clinicians may wish to consider cardiac dose and cardiac risk factors as well as tumor control when making decisions about the use of radiotherapy for breast cancer,” they wrote.

Significant decreases in the dose exposure to the heart can be achieved by changing the patient’s position (from supine to prone, for example) and the field in which the radiotherapy is delivered.3,5 Silvia C. Formenti, MD, chair of the Department of Radiation Oncology at NYU Langone Medical Center, in New York City, commented, “There are ways to limit dose radiation to the heart beyond what was available in the Darby study.”

Dr. Darby adds, “Published studies of tangential radiation, without irradiation of the internal mammary chain, indicate that for patients treated in the prone position, the heart is usually receiving about 1 to 2 Gy. This is similar to the heart dose delivered to patients treated in the supine position with breathing control. It remains to be seen which of these 2 methods will become more popular with oncologists.”

“Clearly,” she continues, “modern radiotherapy planning systems, including patient-specific CT scans, have the potential to increase the ability of radiation oncologists to control the dose to the heart more precisely than has been possible in the past.”

As these issues are sorted out, Dr. Darby urges clinicians to stay focused: “Remember that the most important thing is to cover the target tissue adequately. Compromising on coverage of the target tissue in order to reduce the dose to the heart is likely to be a risky practice,” she says.

Breast Cancer, Radiation Therapy, and Ischemic Heart Disease


image

Breast cancer is the leading cause of cancer deaths in women in the U.S. Survival is better when breast cancer is diagnosed while still local, and 60.8% of women in the U.S. are diagnosed at this stage. In this group of patients, 5-year survival is 98.5%, according to data from the Surveillance, Epidemiology, and End Results (SEER) Program.1 In these cases, surgical treatment with lumpectomy or mastectomy is often followed by radiation therapy.

In fact, a recent meta-analysis of 22 randomized trials provided additional support for the use of postmastectomy radiation in decreasing the rate of mortality related to recurrent cancer and breast cancer in women found to have 1 to 3 positive lymph nodes during mastectomy and axillary dissection.2 As a result of this and other studies, the need to understand the long-term effects of radiation therapy has become more urgent. One of the most important questions is: Does radiotherapy to the chest increase the incidence of ischemic heart disease (IHD)?

The dose of radiation to the breast and heart is now considerably lower than it has been in the past.3 Nonetheless, when malignancies of the right breast are treated with radiation, the heart is typically exposed to a dose of approximately 1 to 2 Gy. Heart exposure is higher for disease of the left breast, of course, and may run up to 10 Gy.4

A recent study assessed how the dose of radiation a woman receives during breast cancer treatment affects her subsequent risk of IHD.

Darby and colleagues performed a case-control study of major coronary events in women who received external beam radiotherapy for invasive breast cancer.4 Major coronary events were defined as myocardial infarction, coronary revascularization, and death from IHD. Their study, recently published in the New England Journal of Medicine (NEJM), included 2168 women who received radiotherapy for breast cancer from 1958 to 2001 in Sweden and Denmark. Of these, 963 women had major coronary events, and 1205 did not and served as controls. Radiation doses to the whole heart and to the left anterior descending artery were estimated based on radiotherapy records.

Mean radiation dose to the heart was 4.9 Gy (range, 0.03 to 27.72). The rate of cardiovascular events increased by 7.4% for each increment of 1 Gy (95% CI, 2.9 to 14.5;P<.001), with no threshold below which there was no risk. This deleterious effect on the heart started within the first 5 years after therapy and continued for at least 20 years. The presence of cardiac risk factors increased the absolute rate of cardiac outcomes but didn’t affect the proportional increase in the rate of major coronary events per Gy.

None of the women in the study received the cardiotoxic chemotherapeutic agents taxanes or trastuzumab, and very few received anthracyclines, thus minimizing these confounders for ischemic outcomes.

Though radiation delivery techniques have improved considerably in recent decades, the incidental exposure of radiation to the heart is always of concern, and strategies to minimize radiation should be exercised whenever possible. Despite this, as Fei-Fei Liu, MD, Professor of Radiation Oncology at the University of Toronto, stated in an editorial that accompanied the Darby article, “It is important to reassure women with breast cancer that with the use of current technologies, the cardiac dose can be decreased considerably, and cardiac risk factors can be better managed.”

Investigator Sarah C. Darby, PhD, of the Clinical Trial Service Unit at the University of Oxford, England, says that “One thing that our studies have shown rather clearly is that any radiation-related risk probably multiplies the risk that a woman already has. Therefore, women who are already at increased risk of heart disease are likely to be at the greatest risk.”

Dr. Darby and her colleagues provided an example of this in the NEJM article:

  • In a 50-year-old woman with no cardiac risk factors at baseline, a 3-Gy dose of radiation to the heart would increase her risk of fatal IHD at age 80 from 1.9% to 2.4% (0.5 percentage points) and her risk of having at least 1 acute coronary event from 4.5% to 5.4% (0.9 percentage points).
  • In a 50-year-old woman with at least 1 cardiac risk factor, a 3-Gy dose of radiation would increase her risk of fatal IHD at age 80 from 3.4% to 4.1% (0.7 percentage points) and her risk of having at least 1 acute coronary event by then by 1.7 percentage points.

In their conclusions, Dr. Darby’s team wrote that because the percentage increase in IHD risk per unit increase in the mean radiation dose to the heart was similar in women with and without cardiac risk factors, one could assume that absolute risk increase at a specific dose was larger for women with preexisting cardiac risk factors.

“Therefore, clinicians may wish to consider cardiac dose and cardiac risk factors as well as tumor control when making decisions about the use of radiotherapy for breast cancer,” they wrote.

Significant decreases in the dose exposure to the heart can be achieved by changing the patient’s position (from supine to prone, for example) and the field in which the radiotherapy is delivered.3,5 Silvia C. Formenti, MD, chair of the Department of Radiation Oncology at NYU Langone Medical Center, in New York City, commented, “There are ways to limit dose radiation to the heart beyond what was available in the Darby study.”

Dr. Darby adds, “Published studies of tangential radiation, without irradiation of the internal mammary chain, indicate that for patients treated in the prone position, the heart is usually receiving about 1 to 2 Gy. This is similar to the heart dose delivered to patients treated in the supine position with breathing control. It remains to be seen which of these 2 methods will become more popular with oncologists.”

“Clearly,” she continues, “modern radiotherapy planning systems, including patient-specific CT scans, have the potential to increase the ability of radiation oncologists to control the dose to the heart more precisely than has been possible in the past.”

As these issues are sorted out, Dr. Darby urges clinicians to stay focused: “Remember that the most important thing is to cover the target tissue adequately. Compromising on coverage of the target tissue in order to reduce the dose to the heart is likely to be a risky practice,” she says.

Battle Of The Booze: Is Fine Wine Over Good Beer Really A Healthy Choice?


Beer vs. wine infographic
In battle of the booze, is fine wine or beer better for your health? 

In life, we are told there are two kinds of people: wine drinkers and beer drinkers. America’s thirst for these two popular alcoholic drinks brings back the age-old debate of beer versus wine. The common belief is a glass of fine wine is healthy, but is it healthier than a foamy, cold glass of beer?

Sip (or guzzle down) these facts about wine and beer to decide which one offers the most life-extending benefits.

Fine Wine: Is It Really So Divine?

Health experts have long lauded wine for its numerous health benefits, specifically its antioxidants, which reduce risk for coronary heart disease. About 200 years ago, an Irish doctor noted chest pain (angina) was far less common in France than in Ireland, according to the Harvard School of Public Health. He attributed this stark distinction to “the French habits and mode of living.” Although the French diet includes plenty of butter and cheese, the country has one of the lowest rates of heart disease in the world, and the French’s high consumption of red wine may be why.

Fine Wine: Heart And Brain Healthy

A study published in the journal Lancet found there was a strong and negative association between ischemic heart disease deaths and alcohol consumption. The findings revealed there is a positive but inconsistent association with cardiac mortality and saturated and monounsaturated fat intake. The correlation seen between less cardiac deaths and alcohol was attributed to wine consumption.

Resveratrol, an antioxidant found in wine, along with the antioxidant compound quercetin, have been shown to benefit the brain. A 2013 study published in the journal Bio Medical Central Medicine found drinking wine could lower the risk for depression. Since resveratrol and quercetin can suppress high levels of C-reactive protein (CRP) — associated with the likelihood of displaying depressive symptoms — it can actually lessen psychological distress associated with depression.

Fine Wine: Which Wine Has The Most Antioxidants?

Wine’s cardioprotective effect has been linked to the antioxidants present in the skin and seeds of red grapes. These antioxidants, such as flavonoids, may help prevent heart disease by increasing levels of good cholesterol, known as high-density lipoprotein (HDL), and protecting against artery damage, says the Mayo Clinic. Researchers at the University of California, Davis, found Cabernet Sauvignon, Petit Syrah and Pinot Noir, are among the wines with the highest concentrations of flavonoids. White wine was found to have significantly smaller amounts than its red counterparts. A rule of thumb is the dryer the red wine, the better it is for a flavonoid boost.

Good Beer: Is It Better?

The majority of medical literature suggests drinking a glass of red wine is drinking to your health, but can a pint of beer do just the same? Similar to its popular counterpart, beer contains antioxidants and important B vitamins, like niacin and folic acid. A single 12-ounce bottle of beer provides up to 12.5 percent of the recommended requirement of vitamin B6, which is known to help cells and be heart healthy, according to eatright.org, part of the Academy of Nutrition and Dietetics.

Good Beer: Bone And Kidney Healthy

Guzzling a pint or two of beer in a matter of seconds may not only turn you into “beercules,” but it can also give you strong bones. Silicon, which is commonly found in whole grains, cereals, and some vegetables, is known to improve bone matrix quality. A 2013 studypublished in the International Journal of Endocrinology noted silicone supplementation in animals and humans has been shown to increase bone mineral density and improve bone strength. However, while drinking moderate amounts of alcohol (wine as well as beer) is related to greater bone density in men and women over 60, they also found bone mineral density was significantly lower in men who drank more than two servings of liquor per day.

Drinking beer can give you good bone health and reduce the risk of developing painful kidney stones by 41 percent. A 2013 study published in the Clinical Journal of the American Society of Nephrology found beer’s anti-kidney stone properties could possibly be due to beer’s high water content and diuretic effect. Soda and punch was found to increase the risk of developing kidney stones as predicted by the researchers.

Beer vs. Wine: Which Is Healthier?

Wine and beer both provide life-extending benefits, respectively, but neither is healthier than the other. It’s not the beverage of choice but rather the frequency of drinking that may matter when reaping alcohol’s benefits. A 2010 study published in the journal Alcoholism: Clinical and Experimental Research found during a 20-year period, those who didn’t drink alcohol suffered from the highest mortality rates at 59 percent, moderate alcohol drinkers who consumed little or no wine at 50 percent rate, and moderate drinkers who consumed mostly wine had a 32 percent mortality rate. Although this study may confirm wine’s health powers, the researchers delved a bit deeper and found that is not the case.

The UT team found wine offered no greater health benefit than beer or liquor after adjusting for lifestyle factors. The truth is any type of alcohol can offer life-extending benefits. Regular, moderate drinking can increase your longevity and improve your overall health in various ways.

So whether you’re a wine or beer drinker, you’ll still reap the benefits of alcohol. Cheers!

Check out CompareCamp.com’s beer vs. wine infographic below for interesting facts and figures about these two alcoholic drinks.

 Trivia, Market Trends & Industry Statistics

Created by: comparecamp.com Author: Emily Bead Join our: FriendFeed

Vitamin D supplementation lacks benefits, study suggests.


The results of a new study suggest that vitamin D supplementation provides little, if any, health benefits.

A meta-analysis of 40 randomized controlled trials found that vitamin D supplementation, with or without calcium, did not alter rates of myocardial infarction or ischemic heart disease, stroke or cerebrovascular disease, cancer, total bone fractures, or hip fractures by a pre-defined risk reduction threshold of 15 percent or more. [Lancet Diabetes Endocrinol 2014. http://dx.doi.org/10.1016/S2213-8587(13)70212-2%5D

“In view of our findings, there is little justification for prescribing vitamin D supplements to prevent [such outcomes],” wrote the study authors, led by Dr. Mark Bolland of the University of Auckland, New Zealand.

The authors also suggested that any further trials similar in design to existing trials are unlikely to alter these conclusions. “Investigators and funding bodies should consider the probable futility of undertaking similar trials of vitamin D to investigate any of these endpoints,” they said.

Previous observational studies have shown that vitamin D deficiency is strongly associated with poor health and even early death. Claims that people can therefore benefit from vitamin D supplementation have been lent strong support by several leading scholars in the field and this has had a major impact on health practitioners prescribing patterns. To illustrate this point, US sales of vitamin D supplements increased by more than 10 times from 2002 to 2011, from US$42 million to $605 million.

In an accompanying editorial, Professor Karl Michaëlsson from Uppsala University in Sweden, said that evidence now suggests that low levels of vitamin D are a consequence, not a cause of poor health, and he cited a report from the US Institute of Medicine emphasizing that both high and low concentrations of vitamin D can lead to health risks in individuals. [J Clin Endocrinol Metab 2011;96:53-58]

“Without stringent indications – ie, supplementing those without true insufficiency – there is a legitimate fear that vitamin D supplementation might actually cause net harm,” said Michaëlsson.

Ischemic Heart Disease: New Recommendations Issued on Primary Care Evaluation, Management.


Guidelines on the evaluation and management of stable ischemic heart disease in the primary care setting have been issued by the American College of Physicians in conjunction with several other organizations.

The guidelines on evaluation stress the importance of making patients’ preferences a part of the decision on further testing. The guidelines include algorithms for diagnosis and risk assessment.

The management guidelines also stress the patient — especially patients’ understanding of their condition and the importance of adhering to treatment regimens and lifestyle changes. Algorithms are also given to guide decision making on revascularization for the purposes of improving symptoms and survival.

Source: Annals of Internal Medicine

 

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