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Effectiveness of single- vs dual-coil implantable defibrillator leads: An observational analysis from the SIMPLE study.
Neuzner, J, Hohnloser, SH, Kutyifa, V, Glikson, M, Dietze, T, Mabo, P, Vinolas, X, Kautzner, J, O'Hara, G, Lawo, T, et al
Journal of cardiovascular electrophysiology. 2019;(7):1078-1085
Abstract
INTRODUCTION Dual-coil leads (DC-leads) were the standard of choice since the first nonthoracotomy implantable cardioverter/defibrillator (ICD). We used contemporary data to determine if DC-leads offer any advantage over single-coil leads (SC-leads), in terms of defibrillation efficacy, safety, clinical outcome, and complication rates. METHODS AND RESULTS In the Shockless IMPLant Evaluation study, 2500 patients received a first implanted ICD and were randomized to implantation with or without defibrillation testing. Two thousand and four hundred seventy-five patients received SC-coil or DC-coil leads (SC-leads in 1025/2475 patients; 41.4%). In patients who underwent defibrillation testing (n = 1204), patients with both lead types were equally likely to achieve an adequate defibrillation safety margin (88.8% vs 91.2%; P = 0.16). There was no overall effect of lead type on the primary study endpoint of "failed appropriate shock or arrhythmic death" (adjusted HR 1.18; 95% CI, 0.86-1.62; P = 0.300), and on all-cause mortality (SC-leads: 5.34%/year; DC-leads: 5.48%/year; adjusted HR 1.16; 95% CI, 0.94-1.43; P = 0.168). However, among patients without prior heart failure (HF), and SC-leads had a significantly higher risk of failed appropriate shock or arrhythmic death (adjusted HR 7.02; 95% CI, 2.41-20.5). There were no differences in complication rates. CONCLUSION In this nonrandomized evaluation, there was no overall difference in defibrillation efficacy, safety, outcome, and complication rates between SC-leads and DC-leads. However, DC-leads were associated with a reduction in the composite of failed appropriate shock or arrhythmic death in the subgroup of non-HF patients. Considering riskier future lead extraction with DC-leads, SC-leads appears to be preferable in the majority of patients.
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Combined Effect of Sauna Bathing and Cardiorespiratory Fitness on the Risk of Sudden Cardiac Deaths in Caucasian Men: A Long-term Prospective Cohort Study.
Laukkanen, JA, Laukkanen, T, Khan, H, Babar, M, Kunutsor, SK
Progress in cardiovascular diseases. 2018;(6):635-641
Abstract
Both cardiorespiratory fitness (CRF) and frequency of sauna bathing (FSB) are each strongly and independently associated with sudden cardiac death (SCD) risk. However, the combined effect of CRF and FSB on SCD risk has not been previously investigated. We evaluated the joint impact of CRF and FSB on the risk of SCD in the Kuopio Ischemic Heart Disease prospective cohort study of 2291 men aged 42-61 years at recruitment. Objectively measured CRF and self-reported sauna bathing habits were assessed at baseline. CRF was categorized as low and high (median cutoffs) and FSB as low and high (defined as ≤2 and 3-7 sessions/week respectively). Multivariable adjusted hazard ratios (HRs) with confidence intervals (CIs) were calculated for SCD. During a median follow-up of 26.1 years, 226 SCDs occurred. Comparing high vs low CRF, the HR (95% CIs) for SCD in analysis adjusted for several established risk factors was 0.48 (0.34-0.67). Comparing high vs low FSB, the corresponding HR was 0.67 (0.46-0.98). Compared to men with low CRF & low FSB, the multivariate-adjusted HRs of SCD for the following groups: high CRF & high FSB; high CRF & low FSB; and low CRF & high FSB were 0.31 (0.16-0.63), 0.49 (0.34-0.70), and 0.71 (0.45-1.10) respectively. In a general male Caucasian population, the combined effect of high aerobic fitness (as measured by CRF) and frequent sauna baths is associated with a substantially lowered risk of future SCD compared with high CRF or frequent sauna bathing alone.
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Natural and unnatural triggers of myocardial infarction.
Kloner, RA
Progress in cardiovascular diseases. 2006;(4):285-300
Abstract
Previous analyses have suggested that factors that stimulate the sympathetic nervous system and catecholamine release can trigger acute myocardial infarction. The wake-up time, Mondays, winter season, physical exertion, emotional upset, overeating, lack of sleep, cocaine, marijuana, anger, and sexual activity are some of the more common triggers. Certain natural disasters such as earthquakes and blizzards have also been associated with an increase in cardiac events. Certain unnatural triggers may play a role including the Holiday season. Holiday season cardiac events peak on Christmas and New Year. A number of hypotheses have been raised to explain the increase in cardiac events during the holidays, including overeating, excessive use of salt and alcohol, exposure to particulates, from fireplaces, a delay in seeking medical help, anxiety or depression related to the holidays, and poorer staffing of health care facilities at this time. War has been associated with an increase in cardiac events. Data regarding an increase in cardiac events during the 9/11 terrorist attack have been mixed. Understanding the cause of cardiovascular triggers will help in developing potential therapies.
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[Reduction of cardiovascular risk in primary prophylaxy of coronary heart disease].
Sobenin, IA, Prianishnikov, VV, Kunnova, LM, Radinovich, EA, Orekhov, AN
Klinicheskaia meditsina. 2005;(4):52-5
Abstract
The purpose of the study was to evaluate the effects of Allicor, an Allium sativum (garlic) preparation with prolonged activity, on 10-year prognostic risk of coronary heart disease (CHD), acute myocardial infarction (MI) and sudden death in patients with elevated and high risk of CHD. 79 patients with elevated and high risk of CHD were included in a double blind randomized placebo-controlled study. They underwent multifactor evaluation of cardiovascular risk by algorithms based on the results of Framingham and Munster studies. Prolonged (12 months) administration of Allicor significantly reduced the multifactor risk, which was demonstrated by a 13.2% (p = 0.005) reduction of prognostic 10-year risk of CHD in men, and a 7.1% (p = 0.040) reduction of the same parameter in women. Prognostic 10-year risk of MI and sudden death in men was reduced by 26.1% (p = 0.025) and did not change significantly in women. In men the main factor of cardiovascular risk reduction was the decrease of cholesterol and low-density lipoprotein concentration by 23.5 +/- 6.6 mg/dl (p = 0.004), and in women - the increase of high-density lipoprotein level by 2.8 +/- 1.5 mg/dl (p = 0.040). The results of the study demonstrate that prolonged Allicor therapy can be applied to the large category of patients who are in need of atherosclerosis prevention.
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Sudden death in familial polymorphic ventricular tachycardia associated with calcium release channel (ryanodine receptor) leak.
Lehnart, SE, Wehrens, XH, Laitinen, PJ, Reiken, SR, Deng, SX, Cheng, Z, Landry, DW, Kontula, K, Swan, H, Marks, AR
Circulation. 2004;(25):3208-14
Abstract
BACKGROUND Familial polymorphic ventricular tachycardia (FPVT) is characterized by exercise-induced arrhythmias and sudden cardiac death due to missense mutations in the cardiac ryanodine receptor (RyR2), an intracellular Ca2+ release channel required for excitation-contraction coupling in the heart. METHODS AND RESULTS Three RyR2 missense mutations, P2328S, Q4201R, and V4653F, which occur in Finnish families, result in similar mortality rates of approximately 33% by age 35 years and a threshold heart rate of 130 bpm, above which exercise induces ventricular arrhythmias. Exercise activates the sympathetic nervous system, increasing cardiac performance as part of the fight-or-flight stress response. We simulated the effects of exercise on mutant RyR2 channels using protein kinase A (PKA) phosphorylation. All 3 RyR2 mutations exhibited decreased binding of calstabin2 (FKBP12.6), a subunit that stabilizes the closed state of the channel. After PKA phosphorylation, FPVT-mutant RyR2 channels showed a significant gain-of-function defect consistent with leaky Ca2+ release channels and a significant rightward shift in the half-maximal inhibitory Mg2+ concentration (IC50). Treatment with the experimental drug JTV519 enhanced binding of calstabin2 to RyR2 and normalized channel function. CONCLUSIONS Sympathetic activation during exercise induces ventricular arrhythmias above a threshold heart rate in RyR2 mutation carriers. Simulating the downstream effects of the sympathetic activation by PKA phosphorylation of RyR2 channels containing these FPVT missense mutations produced a consistent gain-of-function defect. RyR2 function and calstabin2 depletion were rescued by JTV519, suggesting stabilization of the RyR2 channel complex may represent a molecular target for the treatment and prevention of exercise-induced arrhythmias and sudden death in these patients.
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The molecular basis of cardiac arrhythmias in patients with cardiomyopathy.
Ji, S, Cesario, D, Valderrabano, M, Shivkumar, K
Current heart failure reports. 2004;(3):98-103
Abstract
Cardiac arrhythmias are a leading cause of mortality and morbidity in Western society. In some specific instances, these arrhythmias are caused by abnormalities of cardiac ion channels, such as sodium, calcium, and potassium channels, which carry ionic currents and are fundamental determinants of cardiac excitability. Abnormalities of these ion channels are attributed to mutations in the genes encoding the channel protein and cause altered function of channels, which can predispose to arrhythmias. During heart failure, many channels also malfunction because of altered expression, resulting in lethal arrhythmias.
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Impact of sodium-hydrogen exchange inhibition by cariporide on death or myocardial infarction in high-risk CABG surgery patients: results of the CABG surgery cohort of the GUARDIAN study.
Boyce, SW, Bartels, C, Bolli, R, Chaitman, B, Chen, JC, Chi, E, Jessel, A, Kereiakes, D, Knight, J, Thulin, L, et al
The Journal of thoracic and cardiovascular surgery. 2003;(2):420-7
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Abstract
OBJECTIVES To evaluate the effects of cariporide on all-cause mortality or myocardial infarction at 36 days in patients at risk of myocardial necrosis after coronary artery bypass graft surgery. METHODS In the coronary artery bypass graft cohort of the GUARD During Ischemia Against Necrosis trial, patients > or =18 years who required urgent coronary artery bypass graft, repeat coronary artery bypass graft, or had a history of unstable angina and > or =2 risk factors (age >65 years, female gender, diabetes mellitus, ejection fraction <35%, or left main or 3-vessel disease) were randomized to placebo (n = 743) or cariporide 20 mg (n = 736), 80 mg (n = 705), or 120 mg (n = 734). A 1-hour intravenous infusion was initiated shortly before surgery and administered every 8 hours for 2 to 7 days. Patients were followed up for 6 months. A nonparametric covariance analysis was used to calculate the primary efficacy endpoint. RESULTS Baseline characteristics were similar between treatment groups. The cariporide 20- and 80-mg groups had event rates similar to placebo. The endpoint of all-cause mortality or myocardial infarction at day 36 was significant with cariporide 120 mg versus placebo (event rate 12.2% vs 16.2%; P =.027). The risk reduction was evident on postoperative day 1 (3.3% vs 6.5%; P =.005) and was maintained at 6 months (event rate 15.0% vs 18.6%; P =.033). Cariporide was well tolerated, and most adverse events were mild and transient in this high-risk population. CONCLUSIONS Clinical benefit with cariporide 120 mg was observed early after treatment initiation and continued for 6 months postsurgery, suggesting that sodium-hydrogen exchange inhibition with cariporide is cardioprotective in patients undergoing high-risk coronary artery bypass graft surgery.
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[Drug therapy of ventricular arrhythmias - a contemporary perspective].
Grönefeld, GC, Hohnloser, SH
Deutsche medizinische Wochenschrift (1946). 2002;(43):2280-4
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[Heart failure and sudden cardiac death: pharmacological and nonpharmacological treatment possibilities from the viewpoint of the rhythmologist].
Schmitt, C
Zeitschrift fur Kardiologie. 2000;:55-9
Abstract
Recent multicenter studies have shown that the implantable cardioverter defibrillator (ICD) is superior compared to antiarrhythmic agents after sudden cardiac death (SCD) in patients with congestive heart failure. Further ICD studies have to be performed for primary prevention of SCD in patients with heart failure. Primary prevention studies of SCD with Amiodarone or new class III agents (e.g., Dofetilide) were not able to lower cardiac mortality in these patients. How much the new method of biventricular pacing in patients with heart failure and left bundle branch block will reduce cardiac mortality has to be proven in future prospective trials.