An assessment of the safety, hemodynamic response, and diagnostic accuracy of commonly used vasodilator stressors in patients with severe aortic stenosis.

BACKGROUND: Increasing numbers of patients are undergoing transcatheter aortic valve replacement, which often involves assessment of coronary artery disease ischemic burden. The safety and diagnostic accuracy of vasodilator stress agents in patients with severe aortic stenosis (AS) undergoing SPECT myocardial perfusion imaging (MPI) has not been established. METHODS: Patients with severe AS (valve area <1 cm2) on echocardiography who underwent vasodilator stress SPECT MPI at two centers were identified. Patients with aortic valve intervention prior to MPI or who underwent concurrent exercise during stress testing were excluded. AS patients were matched to controls without AS based on age, gender, BMI, ejection fraction, and stress agent. Symptoms, serious adverse events, hemodynamic response, and correlation to invasive angiography were assessed. RESULTS: A total of 95 cases were identified with 45% undergoing regadenoson, 31% dipyridamole, and 24% adenosine stress. A significant change in systolic blood pressure (BP), cases vs controls, was observed with adenosine [-17.9 ± 20.1 vs -2.6 ± 24.9 P = .03)], with a trend toward significance with regadenoson [-16.8 ± 20.3 vs -9.4 ± 17.9 (P = .08)] and dipyridamole [-17.8 ± 20.6 vs -9.0 ± 12.1 (P = .05)]. The change in heart rate was significantly different only for adenosine [5.3 ± 16.8 vs 14.2 ± 10.8 (P = .04)]. Overall, 45% of cases vs 24% of controls (P = .004) had a >20 mmHg decrease in systolic BP. Age, BMI, and resting systolic BP were related to a >20 mmHg decrease in systolic BP on univariate analysis, although only higher resting systolic BP was a predictor on multivariate analysis. In 33 patients who underwent angiography, the sensitivity, specificity, and diagnostic accuracy of vasodilator stress MPI was 77%, 69%, and 73%, respectively. No serious adverse events occurred in the severe AS patients. CONCLUSION: Severe AS patients are more likely to have a hemodynamically significant decrease in systolic BP with vasodilator stress. There were no serious adverse events in this severe AS cohort with good diagnostic performance of MPI compared to angiography.

Successful permanent pacemaker explantation after diagnosis and treatment of Lyme carditis complete heart block: a case report.

Background: Lyme carditis (LC) complete heart block (CHB) is typically treated with i.v. antibiotics without requiring permanent pacing. In patients with high degree atrioventricular (AV) block, suspicious index in Lyme carditis (SILC) scoring is highly sensitive for diagnosing LC. Case summary: We present a case of CHB where a permanent pacemaker (PPM) was implanted prior to LC diagnosis. Suspicious index in Lyme carditis score was 2 at the time of exam, indicating a low risk for LC. However, per further discussion at follow-up, his score was retroactively increased to an intermediate risk of 4 and Lyme titres returned positive. An outpatient oral antibiotic regimen was given, and 2 months later, the patient had <0.1% V-pacing on interrogation with a subsequent unremarkable event monitor. The pacemaker was removed after considerations ensuring full conduction recovery. The patient is doing well at follow-up > 1 year. Discussion: Lyme carditis spontaneous resolution of CHB is common. Once safe extraction parameters have been established, it is appropriate to engage patients without ongoing pacer requirements about explantation of their PPM. For CHB patients without clear aetiology, SILC scoring may be a predictive measure to help prevent unnecessary PPM placement in the future.

Bachmann's Bundle's Unique Physiology: Reviewing How it Made an Atypical Flutter Even More Atypical.

A 69-year-old man with a history of previous ablation and cardiac surgery was found on cardiac electrophysiology study to have a macro-re-entrant left atrial flutter initially misdiagnosed as a micro-re-entrant right atrial tachycardia resulting from the unique conduction properties of Bachmann's bundle. (Level of Difficulty: Advanced.).

Cardioembolic stroke in a young male with cor triatriatum sinister: a case report.

BACKGROUND: Cor triatriatum sinister (CTS) is a rare congenital cardiac anomaly defined by a fibromuscular membrane which bisects the left atrium. Cor triatriatum sinister has been associated with cardioembolic stroke through mechanisms including stagnation of blood flow within the left atrium, an association with atrial fibrillation (AF), and/or an accompanying atrial septal defect (ASD) or patent foramen ovale. We describe a case highlighting the role that CTS may play in cardioembolic stroke, provide high-quality computed tomography angiography and two- and three-dimensional echocardiography of the CTS membrane, and outline management strategies for this uncommon clinical scenario. CASE SUMMARY: A 35-year-old man with no prior medical history presented with acute onset weakness and aphasia. He was found to have an embolic stroke with left M1 and A1 occlusions and received tissue plasminogen activator followed by mechanical thrombectomy with successful recanalization. A thorough stroke workup revealed CTS with an associated ASD as well as potential protein C deficiency. He was managed with indefinite anticoagulation with apixaban. DISCUSSION: This is the 13th reported case of CTS associated with stroke. In most previous cases evidence of blood stasis or frank thrombus was associated with the CTS membrane, and/or existing AF was noted. In this case, none of these were identified, particularly highlighting the surreptitious risk of CTS. In addition, the presence of potential protein C deficiency in this case compounded the risk for thromboembolism and factored into multidisciplinary management decisions.