What is this rhythm? Is there AV block?

Case written and submitted by Elzada Sercus M.D., peer reviewed by Pendell Meyers, Steve Smith, and Ken GrauerA 31-year-old female with a history of low blood pressure and episodes of lightheadedness developed near syncope on postpartum day one after an uncomplicated c-section. She has no other past medical history and does not take any medications. She has no family history of sudden cardiac death or premature coronary artery disease. Given the patient ' s near syncope, an ECG was obtained and when the patient was placed on continuous telemetry monitoring was found to have frequent PVCs. She did not experience any palpitations or sensation of heart racing during the episodes recorded.  She was not having any chest pain at the time the ECG was performed or at any point preceding or during her near syncopal episodes. Telemetry monitoring showed sinus rhythm with occasional bradycardia in the 40s-60s, as well as frequent PVCs. Blood pressure ranges were 98-113 mmHg systolic and 82-68 mmHg diastolic which were baseline for this patient. Potassium was 3.5 mmol/L and magnesium 1.6 mg/dL, otherwise all laboratory studies were within normal limits. Electrolyte repletion was ordered, and the ECG below was obtained:What do you think? What is the rhythm? Is there any evidence of AV block?Baseline ECG (taken 5 months prior):Presentation ECG annotated:ECG Interpretation:Normal sinus rhythm (each QRS complex is preceded by a P wave) with frequent unifocal PVCs. There a...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs