What is a common manifestation of sick sinus syndrome?

A common manifestation of sick sinus syndrome is characterized by alternating bradycardia and tachycardia, which reflects the syndrome's hallmark of dysfunction in the sinoatrial node—the heart's natural pacemaker. Patients with this condition may experience episodes of slow heart rates (bradycardia) followed by periods of rapid heart rates (tachycardia), often leading to symptoms of palpitations, lightheadedness, or fainting. This variability in heart rhythms is a result of the inadequate pacing activity from the sinoatrial node, leading to irregular heart rates.

In contrast, persistent hypotension is not a direct feature of sick sinus syndrome. Hypotension may occur as a secondary symptom due to decreased cardiac output during bradycardic episodes, but it is not a defining characteristic.

Frequent syncope without palpitations can occur in patients with sick sinus syndrome, but it is often associated with notable intervals of bradycardia or sudden changes in rhythm, which would typically involve palpitations prior to syncope.

A regular heart rate with normal rhythm does not align with the expected presentations of sick sinus syndrome, as this condition primarily encompasses irregularities in heart rhythm, not a sustained normal rhythm.