Myocardial infarction is increasingly recognized as a complication of cocaine abuse. A significant number of persons suffering from myocardial infarction associated with cocaine abuse do not have significant coronary atherosclerosis, and the mechanism for infarction in these patients has remained obscure. This report describes a young man with angiographically normal coronary arteries in whom cocaine abuse produced coronary artery spasm leading to coronary thrombosis and infarction.

Thrombotic thrombocytopenic purpura (TTP) is a multisystem disorder that essentially can affect any organ in the human body. The hallmark of the pathogenesis in TTP is the large von Willebrand factor multimers on platelet-mediated micro-thrombi formation, leading to microvascular thrombosis. Autopsy studies showed that cardiac arrest and myocardial infarction are the most common immediate causes of death in these patients. Clinical manifestations of cardiac involvement in TTP vary dramatically, from asymptomatic elevation of cardiac biomarkers, to heart failure, MI and sudden cardiac death. There is limited knowledge about optimal cardiac evaluation and management in patients with TTP. The absence of typical cardiac symptoms, combined with complicated multi-organ involvement in TTP, may contribute to the under-utilization of cardiac evaluation and treatment. Prompt diagnosis and timely initiation of effective therapy could be critically important in selected cases. Based on our experience and this review of the literature, we developed several recommendations for focused cardiac evaluation for patients with acute TTP: (1) patients with suspected or confirmed TTP should be screened for the potential presence of cardiac involvement with detailed history and physical, electrocardiogram and cardiac enzymes; (2) clinical deterioration of TTP patients warrants immediate cardiac reevaluation; (3) TTP patients with clinical evidence of cardiac involvement should be monitored for telemetry, cardiac biomarkers and evaluated with transthoracic echocardiography. These patients require urgent targeted TTP treatment as well as cardiac-specific treatment. Aspirin therapy is indicated for all TTP patients. Since epicardial coronary artery involvement is rare, cardiac catheterization is usually not required, given the high risk for hemorrhage and kidney injury; (4) we recommend evidence-based medical therapy for ischemic symptoms and heart failure. TTP patients with evidence of cardiac involvement would also benefit from routine cardiology follow up during remission.

BACKGROUND Cardiac catheterization is among the most performed medical procedures in the modern era. There were sporadic reports indicating that cardiac arrhythmias are common during cardiac catheterization, and there are risks of developing serious and potentially life-threatening arrhythmias, such as sustained ventricular tachycardia (VT), ventricular fibrillation (VF) and high-grade conduction disturbances such as complete heart block (CHB), requiring immediate interventions. However, there is lack of systematic overview of these conditions. AIM To systematically review existing literature and gain better understanding of the incidence of cardiac arrhythmias during cardiac catheterization, and their impact on outcomes, as well as potential approaches to minimize this risk. METHODS We applied a combination of terms potentially used in reports describing various cardiac arrhythmias during common cardiac catheterization procedures to systematically search PubMed, EMBASE and Cochrane databases, as well as references of full-length articles. RESULTS During right heart catheterization (RHC), the incidence of atrial arrhythmias (premature atrial complexes, atrial fibrillation and flutter) was low (< 1%); these arrhythmias were usually transient and self-limited. RHC associated with the development of a new RBBB at a rate of 0.1%-0.3% in individuals with normal conduction system but up to 6.3% in individuals with pre-existing left bundle branch block. These patients may require temporary pacing due to transient CHB. Isolated premature ventricular complexes or non-sustained VT are common during RHC (up to 20% of cases). Sustained ventricular arrhythmias (VT and/or VF) requiring either withdrawal of catheter or cardioversion occurred infrequently (1%-1.3%). During left heart catheterizations (LHC), the incidence of ventricular arrhythmias has declined significantly over the last few decades, from 1.1% historically to 0.1% currently. The overall reported rate of VT/VF in diagnostic LHC and coronary angiography is 0.8%. The risk of VT/VF was higher during percutaneous coronary interventions for stable coronary artery disease (1.1%) and even higher for patients with acute myocardial infarctions (4.1%-4.3%). Intravenous adenosine and papaverine bolus for fractional flow reserve measurement, as well as intracoronary imaging using optical coherence tomography have been reported to induce VF. Although uncommon, LHC and coronary angiography were also reported to induce conduction disturbances including CHB. CONCLUSION Cardiac arrhythmias are common and potentially serious complications of cardiac catheterization procedures, and it demands constant vigilance and readiness to intervene during procedures.

Unusually prolonged balloon inflations (PBI) during percutaneous transluminal coronary angioplasty (PTCA) have been utilized in 26 consecutive patients to establish adequate coronary perfusion after shorter inflation times resulted in severe residual stenosis (N = 15), early arterial closure (N = 5), or extensive dissection (N = 6). Inflations lasted 1.5 to 15 min and 23/27 stenoses were successfully dilated. The average reduction in stenosis was 67% (90%-33%). Chest pain occurred in 34% vs. 7% (P less than 0.01), and ST changes occurred during 66% vs. 57% (NS) of PBI vs. short inflations. Four patients required coronary artery bypass surgery in spite of PBI, but none suffered an infarction. Electrocardiograms were unchanged in 22 patients and showed nonspecific ST-T wave changes in four. Cardiac enzymes obtained in nine patients failed to reveal a significant increase in serum concentration. We conclude that PBI is well tolerated and can successfully dilate lesions not responding to short inflations.

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