# Step-by-Step ECG Rhythm Identification Step 1: Examine the ECG Rhythm Strip Let's analyze the given ECG strip: - **Regularity**: The rhythm is regular (R-R intervals are consistent). - **P Waves**: There are more waves than QRS complexes; some P waves are not followed by QRS complexes. - **PR Interval**: The PR interval is constant for the conducted beats. - **Dropped Beats**: Occasionally, a QRS complex is missing (dropped beat) after a P wave. ## Step 2: Analyze Answer Choices 1. **Sinus Rhythm with PVC (Premature Ventricular Contraction)** - Would show a premature, wide QRS complex interrupting a regular rhythm. - Not consistent with the strip. 2. **Atrial Flutter** - Would show sawtooth flutter waves instead of distinct P waves. - Not present here. 3. **Sinus Rhythm with PJC (Premature Junctional Complex)** - Would show an early, abnormal QRS following a P wave or without a P wave. - Not consistent with the strip. 4. **2nd Degree Heart Block Type II (Mobitz II)** - Characterized by some P waves not followed by QRS complexes (dropped QRS) with a constant PR interval for conducted beats. - This matches the ECG strip. ## Step 3: Conclusion - **The correct answer is:** **2nd Degree Heart Block Type II (Mobitz II)** ## Explanation - The ECG shows regular P waves with some not followed by QRS complexes (dropped beats). - The PR interval of conducted beats is constant. - This is classic for **Mobitz II second-degree AV block**. --- ### **Final Answer** **2nd Degree Heart Block Type II** (Mobitz II)