Background-Exercise performed at higher relative intensities has been found to elicit a greater increase in aerobic capacity and greater cardioprotective effects than exercise at moderate intensities. An inverse association has also been detected between the relative intensity of physical activity and the risk of developing coronary heart disease, independent of the total volume of physical activity. Despite that higher levels of physical activity are effective in reducing cardiovascular events, it is also advocated that vigorous exercise could acutely and transiently increase the risk of sudden cardiac death and myocardial infarction in susceptible persons. This issue may affect cardiac rehabilitation. Methods and Results-We examined the risk of cardiovascular events during organized high-intensity interval exercise training and moderate-intensity training among 4846 patients with coronary heart disease in 3 Norwegian cardiac rehabilitation centers. In a total of 175 820 exercise training hours during which all patients performed both types of training, we found 1 fatal cardiac arrest during moderate-intensity exercise (129 456 exercise hours) and 2 nonfatal cardiac arrests during high-intensity interval exercise (46 364 exercise hours). There were no myocardial infarctions in the data material. Because the number of high-intensity training hours was 36% of the number of moderate-intensity hours, the rates of complications to the number of patient-exercise hours were 1 per 129 456 hours of moderate-intensity exercise and 1 per 23 182 hours of high-intensity exercise. Conclusions-The results of the current study indicate that the risk of a cardiovascular event is low after both high-intensity exercise and moderate-intensity exercise in a cardiovascular rehabilitation setting. Considering the significant cardiovascular adaptations associated with high-intensity exercise, such exercise should be considered among patients with coronary heart disease. (Circulation. 2012;126:1436-1440.)Key Words: coronary disease Ⅲ death Ⅲ sudden Ⅲ exercise Ⅲ heart arrest H igh levels of physical activity and aerobic capacity are associated with low risk of cardiovascular disease and mortality. 1-3 Aerobic exercise is therefore strongly recommended both for healthy individuals and for patients with cardiovascular disease to improve cardiovascular health and reduce risk of premature mortality. 4,5 If the total energy expenditure of exercise is held constant, exercise performed at higher relative intensities has been found to elicit a greater increase in aerobic capacity 6 and greater cardioprotective effects than exercise at moderate intensities. 7,8 An inverse association has also been detected between the relative intensity of physical activity and the risk of developing coronary heart disease, independent of the total volume of physical activity. 9,10 Indeed, when exercise is performed at high intensity, as little as a single weekly bout of exercise seems to be sufficient for reducing the risk of cardiovascular death in a large uns...

Stent implantation improved long-term angiographic and clinical results after PTCA of chronic coronary occlusions and is thus recommended regardless of the primary PTCA result.

Summary: Magnesium has previously been used in the treatment of various arrhythmias, but few randomized and prospective studies are available. In a single-blind study, the efficacy and safety of intravenous magnesium sulfate (bolus doses of 5 + 5 mmol followed by infusion of 0.04 mmol/min) versus verapamil(5 + 5 mg followed by 0.1 mg/min) was evaluated in 57 patients with supraventricular arrhythnuas (supraventricular tachycardia, atrial fibrillation, and atrial flutter) of recent onset (less than 1 week). Fifteen (58%) of the patients receiving magnesium (n = 26) converted to sinus rhythm within 4 h, and 16 (62%) within 24 h. Verapamil caused a lower ventricular rate, but only six (1 9%) of the patients (n = 3 1) converted to sinus rhythm within 4 h (p c 0.01) and 16 (52%) within 24 h (NS). No side effects were observed during magnesium infusion, whereas six patients receiving vempamil had to be withdrawn from further study medication due to symptomatic side effects (hypotension in three, cardiac failure in three). Magnesium appears to be an effective and safe dmg for the treatment of supraventricular arrhythmias. The overall efficacy for conversion to sinus rhythm is at least as effective as with verapamil, and its action is more rapid.Key words: arrhythrmas, atrial fibrillation, atrial flutter, magnesium sulfate, verapamil Digitalis glycosides may be effective to lower heart rate in patients with rapid ventricular response, but the efficacy of conversion to sinus rhythm is low. ' Verapamil is a potent calcium-channel-blocking agent which has been widely used to slow the ventricular rate in atrial fibrillation or flutter and to convert paroxysmal SV tachycardia to sinus rhythm." However, this drug may cause atrioventricular block, sinus bradycardia, depression of myocardial contractility, and hypotension. This limits the use of the drug, especially in patients with SV arrhythmias associated with left ventricular (LV) failure and hypotension."Recently sotalo16 and flecainide7 have been shown to be effective in treating SV arrhythmias. These drugs may, however, have pmarrhythnuc properties,8. especially in patients with impaired ventricular function? but also in patients with SV arrhythnuas.lo Flecainide has a moderate depressant effect on ventricular function, which may become clinically significant in patients with irnpaud LV function.Il Evidence of proarrhythrmc effects and undesirable side effects of these drugs warrants alternative antiarrhythmic drug therapy.Magnesium has an essential biochemical and electrophysiological effect upon cardiac cells, including modulation of calcium and potassium channels.12 Magnesium infusion reduces the spontaneous rate of isolated guinea pig atriat3 and canine sinus node,I43 I5 slows down intra-atrial and intraventricular c o n d~c t i o n , '~~~ and suppresses catecholamine-induced abnormal pacemaker activity in guinea pig ventricular muscle cells.I8 Thus, magnesium may have an effect on cardiac arrhythnuas whose mechanisms m increased automaticity18 and reentry cirCuits...

These data demonstrate the long-term safety and clinical benefit of stenting recanalized chronic occlusions. There is a continued risk of late clinical events related to nonstented lesions. Implantation of an intracoronary stent should therefore be considered after successful opening of a chronic coronary occlusion.

In 484 patients with a first myocardial infarction 155 were smokers at the time of infarction. Their unadjusted survival was superior to the non-smokers at 3 months follow-up, with a relative risk of 0.36 (95% confidence interval 0.22-0.59). Major baseline differences existed between the two populations. When these inequalities were taken into account through a multivariate Cox regression the relative risk was increased to 0.55 (95% confidence interval 0.33-0.93), but was still significantly lower than in non-smokers (P = 0.017). No difference in rate of reinfarction was observed between the two populations. The smokers tended to have a 'less serious infarction' than the non-smokers. However, adding variables that accounted for this into the Cox model did not cancel the impact of smoking. From the results it is suggested that the reduced mortality in smokers is due to a thrombus occurring at an earlier stage of the coronary artery disease. Thus, at the time of infarction smokers' left ventricular function tends to be less affected, and this is reflected in the improved survival rate among smokers in the first months after an acute myocardial infarction.