Sick sinus syndrome

Arrhythmias Originating in the Sinus Node Sinus bradycardia Sick sinus syndrome Sinus tachycardia Disorders of Impulseformation ... 

These drug are used cautiously in patients with renal or hepatic disease, bladder obstruction, seizure disorders, sick sinus syndrome, gastrointestinal bleeding, and asthma Individuals with a history of ulcer disease may have a recurrence of the bleeding. 

Many individuals, particularly those who partake in regular vigorous exercise, have heart rates less than 60 bpm. For those individuals, sinus bradycardia is normal and healthy, and does not require evaluation or treatment. However, some individuals develop symptomatic sinus node dysfunction. In the absence of correctable underlying causes, idiopathic sinus node dysfunction is referred to as sick sinus syndrome,12 and occurs with greater frequency with advancing age. The prevalence of sick sinus syndrome is approximately 1 in 600 individuals over the age of 65 years.12... 

Sick sinus syndrome leading to sinus bradycardia may be caused by degenerative changes in the sinus node that occur with advancing age. However, there are other possible etiologies of sinus bradycardia, including drugs (Table 6-2).13... 

Sick sinus syndrome leading to sinus bradycardia occurs as a result of fibrotic tissue in the SA node, which replaces normal SA node tissue.12... 

Long-term management of patients with sick sinus syndrome I requires implantation of a permanent pacemaker.12... 

Sick sinus syndrome Idiopathic sinus node dysfunction leading to symptomatic sinus bradycardia. 

Asymptomatic sinus bradyarrhythmias (heart rate less than 60 beats/min) are common especially in young, athletically active individuals. However, some patients have sinus node dysfunction (sick sinus syndrome) because of underlying organic heart disease and the normal aging process, which... 

Cardiogenic shock preexisting second- or third-degree AV block (if no pacemaker is present) congenital QT prolongation sick sinus syndrome hypersensitivity to disopyramide. 

Conduction abnormalities Use caution in patients with sick sinus syndrome, Wolff-Parkinson-White syndrome or bundle branch block. 

Sick sinus syndrome Use only with extreme caution the drug may cause sinus bradycardia, sinus pause, or sinus arrest. The frequency probably increases with higher trough plasma levels. 

Sick sinus syndrome except in the presence of a functioning ventricular pacemaker. 

Patients with decompensated cardiac failure requiring the use of IV inotropic therapy (such patients should first be weaned from IV therapy before initiating carvedilol) bronchial asthma (see Warninas) or related bronchospastic conditions second- or third-degree AV block sick sinus syndrome or severe bradycardia (unless a permanent pacemaker is in place) cardiogenic shock clinically manifest hepatic impairment hypersensitivity to the drug. 

Cardiovascular effects Drugs that increase cholinergic activity may have vagotonic effects on heart rates (eg, bradycardia). The potential for this action may be particularly important in patients with sick sinus syndrome or other supraventricular cardiac conduction conditions. 

Mazuz M, Friedman ITS. Significance of prolonged electrocardiographic pauses in sinoatrial disease sick sinus syndrome. Am. J. Cardiol. 1983 52 485-9. 

Nielsen JC, Andersen HR, Thomsen PE, et al. Heart failure and echocardiographic changes during longterm follow-up of patients with sick sinus syndrome randomized to single-chamber atrial or ventricular pacing. Circulation 1998 97 987-95. 

Sinus rhythm with a rate of less than 60/min is defined as sinus bradycardia. This bradycardia is usually a physiological response. Pathological and/or symptomatic sinus bradycardia may suggest sinus node dysfunction (see sick sinus syndrome). Vagally induced sinus bradycardia may be responsive to atropine, but only needs to be treated if symptomatic. Atropine doses of less than 0.5 mg may cause a paradoxical increase in vagal bradycardia. 

Inappropriate sinus bradycardia, sinoatrial block, and bradycardia-tachycardia syndrome (bradycardia followed by supraventricular tachyarrhythmias such as atrial fibrillation) are included in this syndrome. Treatment of sick sinus syndrome is generally based upon the patients symptoms. In general, bradycardia... 

Propafenone is contraindicated in the presence of severe or uncontrolled congestive heart failure cardiogenic shock sinoatrial, A-V, and intraventricular disorders of conduction and sinus node dysfunction, such as sick sinus syndrome. Other contraindications include severe bradycardia, hypotension, obstructive pulmonary disease, and hepatic and renal failure. Because of its weak (3-blocking action, propafenone may cause possible dose-related bronchospasm. This problem is greatest in patients who are slow metaboUzers. 

Amiodarone is contraindicated in patients with sick sinus syndrome and may cause severe bradycardia and second-and third-degree atrioventricular block. Amiodarone crosses the placenta and will affect the fetus, as evidenced by bradycardia and thyroid abnormalities. The drug is secreted in breast milk. 

The common side effects seen in chronic therapy (Table 19.3) are mostly related to vasodilation—headaches, dizziness, facial flushing, hypotension, and so forth. High doses of verapamil in elderly patients are known to cause constipation. Serious side effects, especially following the intravenous use of verapamil, include marked negative inotropic effects and depression of preexisting sick sinus syndrome, A-V nodal disease, and... 

Marked effect in presence of sick sinus syndrome and A-V nodal disease. 

Contraindications Atrial fibrillation or flutter, second-or third-degree AVblock or sick sinus syndrome (with functioning pacemaker), ventricular tachycardia... 

Contraindications Sick sinus syndrome/second- or third-degree AV block (except in presence of pacemaker), severe hypotension (less than 90mmFIg, systolic), history of serious ventricular arrhythmias, uncompensated cardiac insufficiency, congenital QT interval prolongation, use with other drugs prolonging QT interval... 

Contraindications Bradycardia bronchospastic disorders cardiogenic shock electrolyte imbalance sinoatrial, AV, and intraventricular impulse generation or conduction disorders, such as sick sinus syndrome or AV block, without the presence of a pacemaker uncontrolled CHF... 

Lithium should not be administered to patients with fluctuating or unstable renal function. Because hthium may affect functioning of the cardiac sinus node, patients with sinus node dysfunction (e.g., sick sinus syndrome) should not receive hthium. Although hthium also has acute and chronic effects on the thyroid, patients with hypothyroidism may receive hthium if the thyroid disease is adequately treated and monitored. Laboratory tests that should be performed before initiation of hthium are listed in Table 5-1. 

Sick sinus syndrome, second- and third-degree AV block, hypotension, cardiogenic shock, bronchospastic pulmonary disease. 

The bradycardia-tachycardia ("sick sinus") syndrome is a definite contraindication to the use of lithium because the ion further depresses the sinus node. T-wave flattening is often observed on the ECG but is of questionable significance. 

Contraindications Hypersensitivity to diltiazem Hypotension Sick sinus syndrome Second- or third-degree AV block Acute myocardial infarction and pulmonary congestion Hypersensitivity to Nifedipine Hypersensitivity to isradipine... 

SSRI selective serotonin reuptake inhibitor (class of drugs used to treat depression, e.g., sertraline) SSS sick sinus syndrome stat immediately (Latin statim ) supl supplement or supplied supp suppository Susp suspension... 

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