The first day of the Zurich Review Course focused on current news in cardiology. What is the benefit of iron deficiency therapy in heart failure? When should which of the three new oral anticoagulants be used? And how common is syncope in athletes, really? New devices were also presented. Especially original: the defibrillator, which is not implanted.
Christine Gstrein, MD, Aarau, Switzerland, provided information on anemia in heart failure (HI). More than half of patients with severe HI have iron deficiency – but not always anemia. The speaker recommended that iron deficiency be sought and, if necessary, treated in any patient with new or worsening HI, because iron deficiency is associated with increased mortality, decreased exercise capacity, and poorer quality of life. With the administration of intravenous iron, these parameters improve, and possibly the risk of hospitalization due to worsening HI also decreases. Oral iron replacement is simple and less costly, but there is little data on efficacy, and patient compliance is often poor because of frequent gastrointestinal side effects and long duration of therapy over several months.
When which anticoagulant?
“The new oral anticoagulants are actually not that new anymore,” said PD Esther Bächli, MD, Uster. “That’s why, instead of the abbreviation NOAK, I advocate the term DOAK, or direct-acting anticoagulants.” There are currently three DOAKs on the market: rivaroxaban (Xarelto®), dabigatran (Pradaxa®) and apixaban (Eliquis®), all of which have recently been approved for the indications atrial fibrillation and deep vein thrombosis. Several other products, which are expected to be approved soon, are in Phase III trials. “I expect that in the future about ten corresponding preparations will be available,” the speaker said. This makes it all the more important to familiarize oneself with the new active ingredients and learn about their advantages and disadvantages.
All available DOAK have a half-life of about twelve hours and are effective for about one day. The effect is similar to that of low-molecular-weight heparins. Bioavailability varies, which should be considered when taking dabigatran; for example, dabigatran has poorer bioavailability than rivaroxaban, which should always be taken with a meal. Interactions are numerous, e.g., with verapamil, amiodarone, erythromycin, rifampicin, St. John’s wort preparations, and certain oncologics. Dr. Bächli recommended that DOAK should be avoided in certain situations and for some patient groups (pregnancy, poor compliance, etc.) (Tab. 1) . It is important to know the dosages precisely and to adjust them to the renal function and age of the patients. Rivaroxaban has the advantage that it only needs to be taken once a day. Currently, no antidotes are available, but four such compounds are being tested in trials; initial results are expected by the end of this year.
New Devices
PD Dr. med. Christian Binggeli, Zurich, reported on the latest news in the field of devices. Relatively new to the market is an implantable defibrillator that is subcutaneous only (SICD), with the lead located above the sternum. The background of this development are complications after implantation, replacement or upgrade of an ICD; these mostly originate from the electrodes (infections, perforations, etc.). The SICD is slightly larger than a normal ICD. The indications are the same as for the ICD, but the SICD does not have bradycardia pacing and is not effective for frequent ventricular tachycardia. Complications such as infections or erosions over the device also occur. The conclusion of the speaker: The SICD does what it is supposed to do (good effect according to studies), the complications are moderate, but it has no other functions besides that as a “shock box”.
Two electrode-free devices are also on the market for pacemakers, resp. shortly before approval. They are anchored in the right ventricle and are (theoretically) easily removable. At the moment, however, these devices have not yet become established because of mechanical problems and complications such as perforations.
Some patients need a defibrillator, but implantation of an ICD is not (yet) possible, for example in patients shortly after a heart attack or with a systemic infection. There is now a defibrillator that can be put on like a vest (LifeVest); the monitor is the size of a small handbag and is carried on a belt or strap. So far, there is no randomized trial on the effect, but there is a registry (VEST registry) whose data are being analyzed – results are expected this year. The speaker also mentioned the two studies IRIS and DINAMIT [1,2]: In these, patients who had a high risk of sudden cardiac death after a heart attack received an ICD implantation. Although the ICDs worked adequately in both studies, they did not improve patient survival.
Syncope in athletes
Syncope in athletes, while feared, is rare overall, said Prof. Thomas Allison, MD, Rochester, USA. In one study, only 6.2% of athletes surveyed reported having experienced syncope in the past five years, and of those syncopes, only 12% were related to athletic activity. The lifetime incidence for syncope is about 35%, with two peaks for ages 15-20 (mainly young women) and 75-80 years. Three forms of syncope are distinguished in athletes: the “post-exercise collapse” and vasovagal and cardiac syncope. In “post-exercise collapse,” the athlete’s legs fail in the first few minutes after exercise, but he or she does not fall and never completely loses consciousness.
It is important to distinguish between vasovagal syncope, which is usually harmless, and cardiac syncope, which requires cardiac evaluation. Typically, vasovagal syncope is accompanied by symptoms such as tinnitus, nausea, vomiting, or sweating; it often occurs during prolonged standing. Typically, cardiac syncope is accompanied by symptoms such as palpitation and chest pain, and it often occurs during exercise or exercise training. Competition on. It is important after syncope to take a detailed history (exact event, family history, personal history related to training and competitions). If cardiac syncope is suspected, the athlete is usually disqualified and may no longer participate in competitions! But that doesn’t have to be the case, Prof. Allison said, because athletes can also be treated (medications, ICD, sympathectomy, etc.) so that participation in competitions is possible again with an acceptable residual risk. When administering medications, it is important to check them against the doping lists. The following measures are recommended for repeated vasovagal syncope:
- Drink enough before and during exercise
- Sitting or lying down as soon as prodromes occur
- Perform strength and endurance exercises in a seated or horizontal position
- Exercise leg muscles to increase pressure in the legs.
Source: Zurich Review Course in Clinical Cardiology, April 9, 2015, Zurich.
Literature:
- Steinbeck G, et al: Defibrillator implantation early after myocardial infarction. N Engl J Med 2009; 361: 1427-1436.
- Hohnloser SH, et al: Prophylactic use of an implantable cardioverter-defibrillator after acute myocardial infarction. N Engl J Med 2004; 351(24): 2481-2488.
CARDIOVASC 2015; 14(3): 28-29
