Common ECG interpretation software mistakes Part III: Computer errors that should never be missed.

Electrocardiogram interpretation software mistakes can lead to incorrect diagnoses and inappropriate treatments. Occasionally, the consequences of not recognizing such mistakes are disastrous. This final chapter on software mistakes describes three relatively common computer errors that should never be missed because not recognizing them can result in stroke, cardiac arrest, and even death. In each of the scenarios covered, we describe the clinical background, and provide simple recommendations on how such mistakes can be easily identified and corrected.

The Heart Remembers: A Case of Cardiac Memory.

An 80-year-old male with a history of atrial fibrillation and a single-chamber ventricular pacemaker presented to the hospital for an elective colonoscopy. He experienced a transient episode of unresponsiveness with seizure-like activity before the procedure. This prompted him to get an EKG showing deep T-wave inversions (TWIs) in the precordial leads on a background of paced beats. Such findings were concerning for an acute and potentially life-threatening process such as myocardial infarction (MI) or intracranial insult. After ruling out any severe conditions, the EKG findings were attributed to cardiac memory, an underdiagnosed cause of deep TWIs in patients with a pacemaker.

High-Degree Atrioventricular Block in a Patient With Asymptomatic COVID-19 Infection: A Case Report.

The first cases of COVID-19 infection were reported as pneumonia of unknown cause in China in December 2019. While respiratory complications remain the hallmark of the disease, multisystem involvement has been well documented. Cardiovascular involvement with potentially lethal myocarditis has been extensively reported in the literature. Reports of conduction system disturbances are much rarer, especially in patients without other signs of cardiac involvement. We present a case of an 88-year-old male with no prior cardiac history who presented to the hospital with obstipation. He was diagnosed with a small bowel obstruction and underwent a lysis of adhesions. During the hospitalization, he developed intermittent bradycardia with a high-degree atrioventricular (AV) block. A decision was made to implant a permanent pacemaker. During a pre-procedure COVID-19 screen, he was found to be positive for the presence of SARS-CoV-2 RNA. He had no signs of myocardial injury, a transthoracic echocardiogram showed no abnormalities, and he remained free of any respiratory symptoms. While the involvement of the cardiac conduction system has been documented in patients with symptomatic COVID-19 infection, our patient only exhibited conduction abnormalities and remained free of other COVID-19 symptoms. The sole involvement of the conduction system by COVID-19 is rare, especially in patients with otherwise asymptomatic infections. There is no long-term data to suggest whether such conduction abnormalities are temporary or permanent. As such, patients might benefit from the implantation of a permanent pacemaker.

Electrocardiographic diagnosis of acute myocardial infarction in a pacemaker patient: a case report.

BACKGROUND: The electrocardiographic diagnosis of acute myocardial infarction (AMI) in the setting of cardiac pacing is often challenging. The original Sgarbossa criteria proposed in 1996 were demonstrated to be valid for diagnosis of AMI in both ventricular paced rhythm and left bundle branch block. To improve accuracy, the modified Sgarbossa criteria (MSC) were proposed. CASE PRESENTATION: We presented a case of electrocardiographic diagnosis of AMI in a pacemaker patient. The Electrocardiogram (ECG) was false negative by using the original Sgarbossa criteria, whereas true positive by the MSC at a ratio of - 0.20. CONCLUSIONS: The application of MSC using an appropriate ratio (- 0.20 or - 0.25) may facilitate a timely diagnosis of AMI. Physicians should carefully choose the appropriate cutoff in a case-by-case basis.

Unmasking an acute coronary occlusive myocardial infarction in patients with right ventricular paced rhythm.

Electrocardiographic recognition of an acute myocardial infarction in the setting of a right ventricular paced rhythm (VPR) represents a unique diagnostic challenge. The classical ST-segment patterns of myocardial ischemia can become obscured by the abnormal repolarization changes caused by a right VPR. Consequently, longer door-to-balloon reperfusion times and a higher mortality have been reported among these patients mostly due to a delayed diagnosis. In this population, the use of the modified Sgarbossa Criteria (SC) can aid the clinician in the diagnosis of an acute coronary occlusive myocardial infarction (OMI), as an ST-segment elevation myocardial infarction (STEMI) equivalent. However, there are only a few validating studies and no specific guidelines endorsing their use in patients with VPR. We present three cases with right VPR in which the use of the modified SC was diagnostic of OMI, as well as predictive of the occluded coronary vessel. Our review of the current evidence favors that identification of at least one modified SC in patients with right VPR represents an OMI finding with a similar accuracy as when these are used in patients with LBBB.

Accuracy of OMI ECG findings versus STEMI criteria for diagnosis of acute coronary occlusion myocardial infarction.

OBJECTIVE: In the STEMI paradigm of Acute Myocardial Infarction (AMI), many NSTEMI patients have unrecognized acute coronary occlusion MI (OMI), may not receive emergent reperfusion, and have higher mortality than NSTEMI patients without occlusion. We have proposed a new OMI vs. Non-Occlusion MI (NOMI) paradigm shift. We sought to compare the diagnostic accuracy of OMI ECG findings vs. formal STEMI criteria for the diagnosis of OMI. We hypothesized that blinded interpretation for predefined OMI ECG findings would be more accurate than STEMI criteria for the diagnosis of OMI. METHODS: We performed a retrospective case-control study of patients with suspected acute coronary syndrome. The primary definition of OMI was either 1) acute TIMI 0-2 flow culprit or 2) TIMI 3 flow culprit with peak troponin T ≥ 1.0 ng/mL or I ≥ 10.0 ng/mL. RESULTS: 808 patients were included, of whom 49% had AMI (33% OMI; 16% NOMI). Sensitivity, specificity, and accuracy of STEMI criteria vs Interpreter 1 using OMI ECG findings among 808 patients were 41% vs 86%, 94% vs 91%, and 77% vs 89%, and for Interpreter 2 among 250 patients were 36% vs 80%, 91% vs 92%, and 76% vs 89%. STEMI(-) OMI patients had similar infarct size and mortality as STEMI(+) OMI patients, but greater delays to angiography. CONCLUSIONS: Blinded interpretation using predefined OMI ECG findings was superior to STEMI criteria for the ECG diagnosis of Occlusion MI. These data support further investigation into the OMI vs. NOMI paradigm and suggest that STEMI(-) OMI patients could be identified rapidly and noninvasively for emergent reperfusion using more accurate ECG interpretation.

Diagnostic accuracy of SPECT and PET myocardial perfusion imaging in patients with left bundle branch block or ventricular-paced rhythm.

BACKGROUND: The difference in diagnostic accuracy of coronary artery disease (CAD) between vasodilator SPECT and PET myocardial perfusion imaging (MPI) in patients with left bundle branch block (LBBB) or ventricular-paced rhythm (VPR) is unknown. METHODS: We identified patients with LBBB or VPR who underwent either vasodilator SPECT or PET MPI and subsequent coronary angiography. LBBB/VPR-related septal and anteroseptal defects were defined as perfusion defects involving those regions in the absence of obstructive CAD in the left anterior descending artery or left main coronary artery. RESULTS: Of the 55 patients who underwent coronary angiography, 38 (69%) underwent SPECT and 17 patients (31%) underwent PET. PET compared to SPECT demonstrated higher sensitivity (88% vs 60%), specificity (56% vs 14%), positive predictive value (64% vs 20%), negative predictive value (83% vs 50%), and overall superior diagnostic accuracy (AUC .72 (95% CI .50-.93) vs .37 (95% CI .20-.54), P = .01) to detect obstructive CAD. LBBB/VPR-related septal and anteroseptal defects were more common with SPECT compared to PET (septal: 72% vs 17%, P = .001; anteroseptal: 47% vs 8%, P = .02). CONCLUSIONS: PET has higher diagnostic accuracy when compared to SPECT for the detection of obstructive CAD in patients with LBBB or VPR.

Prognostic value of regadenoson stress myocardial perfusion imaging in patients with left bundle branch block or ventricular paced rhythm.

BACKGROUND: Vasodilator stress myocardial perfusion imaging (MPI) is the provocative test of choice in patients with left bundle branch block (LBBB) or ventricular paced (V-paced) rhythm. The prognostic value of regadenoson SPECT myocardial perfusion imaging (MPI) in these patients has not been studied. METHODS AND RESULTS: We conducted a retrospective cohort study of 562 patients [mean age, 69 ± 11 years; men, 53.3%] with LBBB (50.7%) or V-paced rhythm (49.3%) who underwent regadenoson stress SPECT-MPI. There were 321 (57.1%) subjects with abnormal MPI and 192 (34.2%) with myocardial ischemia. During a mean follow-up of 2.5 ± 1.9 years, 39 (6.9%) patients had a major adverse cardiac event (MACE), defined as cardiac death or myocardial infarction. The annualized MACE rate in patients with normal MPI was 0.9% (LBBB, 0.8%; V-paced, 1.0%). There was a significant stepwise increase in MACE rates with increasing burdens of perfusion abnormality (P < 0.001) and myocardial ischemia (P = 0.001). Increased risk with abnormal MPI [adjusted hazard ratio, 4.26; P = 0.001] and myocardial ischemia [adjusted hazard ratio, 2.70; P = 0.003] was independent of and incremental to important clinical covariates. Abnormal MPI and myocardial ischemia predicted MACE similarly in both LBBB and V-paced subgroups (interaction P values > 0.05). CONCLUSION: In patients with LBBB and V-paced rhythm, regadenoson stress SPECT-MPI provides independent and incremental prognostic value in predicting adverse cardiac events.

Rare and Fascinating Case of ST-Elevation Myocardial Infarction Diagnosis From an Underlying Ventricular Paced Rhythm.

This is a case of a patient diagnosed with anterior ST-elevation myocardial infarction (STEMI) with a ventricular paced rhythm after the patient underwent a femoral-femoral bypass surgery for severe peripheral vascular disease. The case highlights the diagnosis of STEMI in the setting of paced rhythm in the appropriate clinical setting.

Sgarbossa criteria used to identify cardiac ischemia in patient with ventricular paced rhythm.

There is a paucity of research on how the Sgarbossa criteria perform in patients with ventricular pacing. However, the limited research that exists suggests that the criteria are specific, but not sensitive, for myocardial ischemia in this population. We present the case of a 73-year-old man who presented to the ED with acute chest pain. His previous medical history was significant for hypertension and a pacemaker due to type 2 s-degree AV block. His initial ECG fulfilled all three Sgarbossa criteria and subsequent coronary angiography identified a culprit lesion in the posterior descending artery. In this case, awareness of the Sgarbossa criteria's applicability in patients with ventricular paced rhythm facilitated earlier identification of ischemia and subsequent intervention.