Characterizing Mechanisms of Ischemia in Patients With Myocardial Bridges.

BACKGROUND: Myocardial bridges (MBs) are prevalent and can be associated with acute and chronic ischemic syndromes. We sought to determine the substrates for ischemia in patients with angina with nonobstructive coronary arteries and a MB in the left anterior descending artery. METHODS: Patients with angina with nonobstructive coronary arteries underwent the acquisition of intracoronary pressure and flow during rest, supine bicycle exercise, and adenosine infusion. Coronary wave intensity analysis was performed, with perfusion efficiency defined as accelerating wave energy/total wave energy (%). Epicardial endothelial dysfunction was defined as a reduction in epicardial vessel diameter ≥20% in response to intracoronary acetylcholine infusion. Patients with angina with nonobstructive coronary arteries and a MB were compared with 2 angina with nonobstructive coronary arteries groups with no MB: 1 with coronary microvascular disease (CMD: coronary flow reserve, <2.5) and 1 with normal coronary flow reserve (reference: coronary flow reserve, ≥2.5). RESULTS: Ninety-two patients were enrolled in the study (30 MB, 33 CMD, and 29 reference). Fractional flow reserve in these 3 groups was 0.86±0.05, 0.92±0.04, and 0.94±0.05; coronary flow reserve was 2.5±0.5, 2.0±0.3, and 3.2±0.6. Perfusion efficiency increased numerically during exercise in the reference group (65±9%-69±13%; P=0.063) but decreased in the CMD (68±10%-50±10%; P<0.001) and MB (66±9%-55±9%; P<0.001) groups. The reduction in perfusion efficiency had distinct causes: in CMD, this was driven by microcirculation-derived energy in early diastole, whereas in MB, this was driven by diminished accelerating wave energy, due to the upstream bridge, in early systole. Epicardial endothelial dysfunction was more common in the MB group (54% versus 29% reference and 38% CMD). Overall, 93% of patients with a MB had an identifiable ischemic substrate. CONCLUSIONS: MBs led to impaired coronary perfusion efficiency during exercise, which was due to diminished accelerating wave energy in early systole compared with the reference group. Additionally, there was a high prevalence of endothelial and microvascular dysfunction. These ischemic mechanisms may represent distinct treatment targets.

Sudden Cardiac Death in Ischaemic Cardiomyopathy and the Primary Prevention ICD: Time for a More a Personalised Approach?

Guidelines recommend primary prevention implantable cardioverter defibrillator (PPICD) for left ventricular ejection fraction (LVEF) <35% only after 3 months of optimal medical therapy (OMT) or 6 weeks after acute MI with persistent LVEF dysfunction. A 73-year-old woman presented with decompensated heart failure secondary to ischaemic cardiomyopathy. Severe coronary disease with sufficient dysfunctional myocardial segments on cardiac MRI suggested potential benefit from revascularisation. Following discussion with the heart team, she underwent percutaneous coronary intervention (PCI). PPICD implantation was deferred as per guideline recommendations. However, 20 days post-PCI, the patient died from malignant ventricular arrhythmia captured on a Holter monitor. This case demonstrates that some high-risk patients may not receive a potentially life-saving PPICD if guidelines are stringently adhered to. We highlight evidence that LVEF alone is of limited value in a risk assessment of arrhythmogenic death, and postulate that a more personalised ICD prescription should be considered using scar characteristics on cardiac MRI to prompt upstream ICD implantation in high-risk patients.

Assessment and Management of Ischaemic Heart Disease in Non-Cardiac Surgery.

In the setting of non-cardiac surgery, cardiac complications contribute to over a third of perioperative deaths. With over 230 million major surgeries performed annually, and an increasing prevalence of cardiovascular risk factors and ischaemic heart disease, the incidence of perioperative myocardial infarction is also rising. The recent European Society of Cardiology guidelines on cardiovascular risk in noncardiac surgery elevated practices aiming to identify those at most risk, including biomarker monitoring and stress testing. However the current evidence base on if, and how, the risk of cardiac events can be modified is lacking. This review focuses on patient, surgical and cardiac risk assessment, as well as exploring the data on perioperative revascularization and other risk-reduction strategies.

Extensive aortic thrombosis and testicular infarction - a rare complication of biventricular cardiac thrombi.

Heart failure is a heterogenous syndrome which is increasing in prevalence, with a prognosis worse than many malignancies. Morbidity and mortality most commonly occur secondary to pump failure or ventricular arrhythmias; however, a more infrequently seen complication is the formation of mural thrombi. More commonly seen within the left ventricle, thrombi can embolize leading to stroke or end organ infarction. We present the case of a male who presented with decompensated heart failure. The presence of biventricular thrombi was found on echocardiography and subsequent cross-sectional imaging revealed these had embolized resulting in the rare complication of extensive abdominal aortic thrombosis with renal and testicular infarction. Biventricular thrombi are rare but high risk due to the potential for embolization as demonstrated in this case. Prompt recognition and management with anti-coagulation are essential, followed by treatment of the underlying pathology, which resulted in the formation of thrombi to prevent recurrence.