**Core Concept**
Atrial septal defects (ASDs) are a type of congenital heart defect characterized by an abnormal opening in the atrial septum, allowing blood to flow between the left and right atria. This defect can lead to various clinical manifestations due to the altered hemodynamics and increased workload on the right heart.

**Why the Correct Answer is Right**
Atrial septal defects are typically associated with features such as a fixed splitting of the second heart sound (S2), a holosystolic murmur at the left upper sternal border, and an increased risk of pulmonary hypertension and right heart failure. The increased flow to the lungs can also lead to clubbing of the fingers and pulmonary plethora on chest X-ray. Additionally, ASDs are often associated with a "fixed" or "widened" splitting of S2 due to the increased flow across the pulmonary valve.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it is a feature of ASDs, not a characteristic that distinguishes it from other conditions.

**Option B:** This option is incorrect as it is not a typical feature of ASDs. While patients with ASDs may have a wide pulse pressure, it is not a distinguishing characteristic.

**Option C:** This option is incorrect as it is a feature of ASDs. The increased flow to the lungs can lead to a variety of pulmonary changes, including clubbing.

**Option D:** This option is incorrect as it is not a typical feature of ASDs. While patients with ASDs may have a variety of arrhythmias, this is not a distinguishing characteristic.

**Clinical Pearl / High-Yield Fact**
One key point to remember is that ASDs are often associated with a fixed or widened splitting of S2, which can be a helpful clinical clue in diagnosis.

**Correct Answer: D. Atrial septal defect typically presents with increased pulmonary blood flow, clubbing, and a fixed splitting of S2, not with arrhythmias as a primary feature.**