Loss of atrial pacing in a patient with a dual-chamber permanent pacemaker: What is the mechanism?

Paramedic Ability in Interpreting Electrocardiogram with ST-segment Elevation Myocardial Infarction (STEMI) in Saudi Arabia

Objective

To evaluate paramedic ability in recognizing 12-lead Electrocardiogram (ECG) with ST-segment Elevation myocardial infarction (STEMI) in Saudi Arabia.

Methods

This is a quantitative exploratory cross-sectional study using an electronic survey of paramedics was conducted between June and September 2021. The survey included demographics, educational and clinical experiences, and multiple 12-lead ECG strip questions to assess participants’ ability to recognize STEMI. We reported the overall sensitivity, specificity, and correct proportions with 95% Confidence Intervals (CI).

Results

Eighty-four paramedics completed the survey, and 65% of them were between 24 and 29 years old, with a median, of three years of field experience. Overall sensitivity and specificity were 58.39% (95% CI, 50.4% to 66.1%) and 29.01% (95% CI, 25.15% to 33.1%), respectively. In total, 67.1% correctly identified inferior STEMI, whereas only 50% correctly identified lateral STEMI. Both STEMIs were correctly identified by 41%, and the majority misinterpreted STEMI mimics (ECG rhythms with similar ECG morphology to STEMI). The proportion who correctly recognized left bundle branch block was 14.8%, pericarditis was 10.9%, and ventricular pacing was 1.4%. However, almost third of participants correctly identified right bundle branch block (32.9%) and left ventricle hypertrophy (30.7%). Overall, there was no correlation between the correct ECG interpretation of STEMIs and educational and clinical experiences.

Conclusion

Paramedics were able to identify STEMI events in prehospital settings with moderate sensitivity and low specificity with limited ability to differentiate between STEMI and STEMI mimics. Therefore, additional training in ECG interpretation could improve their clinical decision-making, and to ensure that proper care and treatment is provided. Further research on a large, representative sample of paramedics across the country could provide more definitive evidence to establish a greater degree of accuracy in detecting STEMI in prehospital settings.

A Rare Case of Complete Fragmentation of Pacemaker Lead after a High-Velocity Theme Park Ride

Pacemaker lead fracture is one of the most common causes of pacemaker malfunction and is most frequently associated with weight lifting or chest trauma. These patients usually present with symptoms of dizziness, syncope, chest discomfort, and palpitations or less commonly with extracardiac symptoms. Diagnosis is made by ECG and careful review of chest imaging such as chest X-ray or fluoroscopy. Treatment involves placement of a new lead with or without extraction of the fractured lead. We present an interesting case of complete severance of the tip of a dual-chamber pacemaker's atrial lead after a high-velocity theme park ride. In our case, the fracture occurred during amusement park rides and went undiagnosed until the patient presented for routine pacemaker evaluation. This case indicates that extreme physical forces in the absence of direct trauma, such as during amusement park rides, may result in lead fractures and patients with pacemakers should be cautioned regarding such activities.