Alternating pulse

Specialty: Cardiovascular.

• pulsus alternans
• alternating variation in the strength of the arterial pulse

Why it occurs

• Severe left ventricular failure (LVEF <30%)
• Advanced idiopathic or ischemic dilated cardiomyopathy
• Critical aortic stenosis in the phase of myocardial decompensation
• Paroxysmal supraventricular or sustained ventricular tachycardia
• Severe acute myocarditis with compromised contractility

Initial workup

12-lead electrocardiogram to identify signs of acute myocardial ischemia, left ventricular hypertrophy or electrical alternans (associated with tamponade); Transthoracic echocardiogram to accurately quantify ejection fraction, left ventricular end-systolic and end-diastolic volumes, and rule out valvular or obstructive structural heart disease; Invasive intra-arterial pressure monitoring (arterial line) to confirm and record beat-to-beat variation in systolic pulse pressure.

Standard management

• Levosimendan — calcium sensitizer with inotropic and vasodilator effect, indicated in the acute decompensation of severe heart failure without marked hypotension refractory to standard treatment; infusion of 0.05 to 0.2 mcg/kg/min over 24 hours
• Dobutamine — beta-adrenergic inotropic agent to improve ventricular contractility; 2 to 5 mcg/kg/min in continuous intravenous infusion, adjusting according to electrocardiographic monitoring for risk of arrhythmias
• Nitroglycerin — venous and coronary arterial vasodilator to reduce ventricular preload and afterload, useful if there is associated pulmonary congestion; infusion of 5 to 100 mcg/min, contraindicated if SBP <90 mmHg
• Furosemide (loop diuretic for the management of associated volume overload; 40 mg intravenous bolus, with reevaluation of the diuretic response at 2 and 6 hours).