Ventricular arrhythmias. Preventing sudden death with drugs and ICD devices

Sudden cardiac death occurs most frequently in persons age 50 to 60, and serious ventricular arrhythmias are the cause of death in most cases. The underlying substrate is usually CAD, either a healed infarction or an acute ischemic event. Early studies using antiarrhythmic drugs to improve post-MI survival led instead to increased mortality, casting doubt on this approach. A cascade of studies using newer antiarrhythmic drugs showed some promise in selected patients post MI. Another approach--using implantable defibrillators--may show greater benefit than antiarrhythmic drugs in patients at serious risk, but the widespread implantation of these devices may be cost-prohibitive. Management of serious ventricular arrhythmias is guided by the individual patient's comorbidities, cardiac function, history of ischemia, and perceived risk of sudden death.

Heart failure: clinical implications of systolic and diastolic dysfunction

Morbidity and mortality from congestive heart failure (CHF) remain high for older patients with systolic or diastolic dysfunction. These two disease processes differ in clinical manifestations, physical findings, treatment options, and prognosis. No one physical findings is diagnostic, which underlines the importance of assessing LV function with Doppler echocardiography. Diastolic dysfunction has been shown to increase with age, although most data demonstrating effective medical therapy for CHF applies to patients with systolic dysfunction. The treatment of older patients with preserved systolic function and CHF is therefore difficult, due to incomplete understanding of diastolic dysfunction and limited data about specific drug therapies.

Heart protection: controlling risk factors for cardiovascular disease

Cardiovascular disease is the leading cause of illness and death in the United States. Clinical data continue to support primary prevention through the aggressive treatment of well-defined cardiovascular risk factors. Three risk factors that can be modified to lower the risk of cardiovascular disease and death are hypercholesterolemia, hypertension, and cigarette smoking. Even patients with asymptomatic cardiovascular disease have been shown to benefit from aggressive cholesterol-lowering therapy. New JNC-VI guidelines for managing hypertensive disease recommend that treatment decisions be based on level of blood pressure plus presence or absence of target organ damage or other risk factors. The risk of myocardial infarction in former smokers approaches that of nonsmokers after 3 years.

Sudden cardiac death from coronary artery spasm in a healthy subject

The true incidence of sudden cardiac death (SCD) from coronary artery spasm is unknown. The following case involves SCD in a previously asymptomatic young man with reasonable evidence to implicate coronary artery spasm as a potential cause for his clinical event. Ergonovine provocation may be warranted in patients who present with SCD and no discernable cause.

Simultaneous assessment of left ventricular perfusion and function with technetium-99m sestamibi after coronary artery bypass grafting

This study examined the left ventricular perfusion and EF by using simultaneous SPECT and first-pass radionuclide angiography with technetium 99m sestamibi in 95 patients after uncomplicated coronary artery bypass grafting. The patients were divided into those with normal EF and no previous myocardial infarction before surgery (group 1, n = 57), and those with abnormal EF or infarction (group 2, n = 38). The SPECT images were normal in 37 patients in group 1 and in 6 patients in group 2 (p < 0.0001). The patients with normal SPECT images had a higher EF after surgery than those with abnormal images (65% +/- 10% vs 50% +/- 14%, p < 0.0001) and was higher in group 1 than in group 2 (64% +/- 8% vs 46% +/- 16%, p < 0.0001). There was a significant correlation between the EF and the extent of perfusion abnormality (r = -0.44, p < 0.0001). The patients with normal SPECT images could not be separated from those with abnormal images based on peak CK, CK-MB, and the electrocardiographic changes. Of the 69 patients with postoperative EF > or = 50%, the perfusion pattern was normal in 41 and abnormal in 28; of the 26 patients with EF < 50%, 24 had abnormal SPECT (p < 0.003). There was no significant change in mean EF after surgery (55% +/- 14% before vs 56% +/- 15% after). Thus simultaneous assessment of left ventricular perfusion and function after coronary artery bypass grafting showed that an abnormal perfusion pattern may exist despite a normal EF. These patients could not be predicted by enzymes or electrocardiographic changes.