Reperfusion in acute myocardial infarction

Diastolic Timed Vibrator: Noninvasive Pre-Hospitalization Treatment of Acute Coronary Ischemia

The speed of intervention is one of the major factors in increasing the survival rate of patients suffering from acute coronary ischemia. The two principal techniques currently in use: pharmacological and interventional, can be employed to re-canalize coronary arteries, but the former is slow acting and often leads to incomplete reperfusion, while the latter requires specialized personnel in a hospital with a cardiac catheterization laboratory. In this paper, we introduce a novel method intended for pre-hospitalization treatment of patients with acute coronary ischemia that can be safely applied by a minimally trained individual prior to or during patient transportation to hospital. It consists in applying low frequency mechanical vibrations to the left intercostal space of patient's chest during diastole of the heart cycle, to induce vibrations of the heart and thus of the coronary arteries. Mechanical vibrations stimulate mixing of blood which improves drug delivery to the occlusion site, applies mechanical force on the clot leading to its faster dissolution and finally acts as a strong vasodilator in case of spasms. We introduce the principle of operation and the architecture of the Diastolic Timed Vibrator (DTV), including a custom ECG processing algorithm, vibration pattern generator and active braking methods. Experimental results demonstrate the functionality of the DTV device and pave way for in-vivo tests necessary for clinical confirmation of the proposed method.

Catheter-induced acute aortic insufficiency with hemodynamic collapse during PTCA: an unreported complication

Primary PTCA as a means of reestablishing coronary blood flow in the infarct related artery is preferable in certain subgroups of patients with acute myocardial infarction. While the success rate of primary PTCA is very high, the procedure is not without risk. We report a case of hemodynamic collapse during PTCA due to an Amplatz guide catheter-induced, acute, and reversible aortic insufficiency. With the increasing use of the left Amplatz catheter for better guide support during PTCA, this unusual and previously unreported complication should be borne in mind.

Community practice of primary angioplasty for myocardial infarction

Results obtained with primary angioplasty at the community level do not duplicate the results of the published trials. Major changes in current community practice patterns are needed to achieve the success rates of the published trials.

Use of direct angioplasty for treatment of patients with acute myocardial infarction in hospitals with and without on-site cardiac surgery. The Myocardial Infarction, Triage, and Intervention Project Investigators

BACKGROUND

In the Myocardial Infarction, Triage, and Intervention (MITI) registry of acute myocardial infarction, 441 (12%) of 3750 patients had direct angioplasty as initial treatment. Approximately half (233) were performed in hospitals with no on-site surgery.

METHODS AND RESULTS

Procedure success rates, use of emergent surgery, and factors influencing outcome were compared in both angioplasty groups as well as with 653 patients treated with thrombolytic therapy in the same hospitals. There was no difference in baseline characteristics between patient groups treated by angioplasty in the two types of hospitals. Patency was established in 88% of patients. Only 1.4% underwent emergent surgery. Overall, survival was 93% but was significantly worse after a failed procedure in all ECG and hemodynamic subsets as well as in those with prior bypass surgery. In a multivariate analysis, age, initial heart rate, blood pressure, and prior bypass surgery but not type of hospital were predictive of survival. Survival rates were similar, but there tended to be fewer strokes (0.6% versus 2.1%, P = .12), shorter hospital stays (7.0 versus 8.1 days, P < .001), and less recurrent ischemia (20% versus 30%, P = .009) in patients treated by angioplasty compared with thrombolysis. Readmission and reinfarction rates were similar for both treatments.

CONCLUSIONS

Observations from this community registry suggest that mortality after direct angioplasty is low and the use of emergent surgery is infrequent. Outcome in this registry study was dependent on initial hemodynamic findings and infarct location but not on the presence of on-site surgery. Compared with thrombolytic therapy, the incidence of complications was the same or lower, but this needs confirmation in randomized trials.

Thrombolytic therapy in acute myocardial infarction following prolonged cardiopulmonary resuscitation

Thrombolytic therapy was administered to a 49-year-old woman with an acute anterior wall myocardial infarction after having prolonged cardiopulmonary resuscitation for 13 minutes. On admission, there was no clinical or radiographic evidence of gross trauma. There was no significant morbidity and the patient recovered to a completely functional status. The literature of thrombolytic therapy after cardiopulmonary resuscitation is reviewed. In the absence of gross trauma from cardiopulmonary resuscitation, thrombolytic therapy in acute myocardial infarction should not necessarily be excluded because of the duration of resuscitation. Further experience with such patients will shed additional light on efficacy and safety.

Mechanical and electrical complications of acute myocardial infarction

Although much of the current enthusiasm in the management of acute myocardial infarction is related to revascularization strategies, mechanical and electrical complications continue to pose a major threat to recovery in some patients. Some of the major complications of acute myocardial infarction are cardiogenic shock, rupture of the free wall and pseudoaneurysm, rupture of the ventricular septum, acute mitral regurgitation, right ventricular myocardial infarction, infarct expansion or extension, pericarditis and tamponade, peri-infarction hypertension, and tachyarrhythmias and bradyarrhythmias. For each of these complications, general guidelines for diagnosis and management are offered. Early, aggressive, and judicious treatment of these complications may substantially decrease the morbidity and mortality associated with acute myocardial infarction.

Acute myocardial infarction: initial manifestations, management, and prognosis

In patients with suspected acute myocardial infarction (AMI), obtaining a thorough history is important for identifying both the cause of chest pain and any concurrent conditions that may complicate the management. Physical examination--including cardiac auscultation and determining the status of the peripheral vasculature--is important as a guide to immediate management and as a baseline for future comparison. The differential diagnosis of AMI is extensive, and various laboratory tests, such as electrocardiography, cardiac enzymes, radionuclide techniques, echocardiography, and cardiac catheterization, can aid in the diagnosis. The routine management of patients with AMI can include medical therapy with antithrombotic agents, nitrates, beta-adrenergic blockers, or calcium channel blocking agents. The major differences between Q-wave and non-Q-wave infarction are discussed. Some factors that affect early and late prognosis in patients with AMI are age of the patient, residual left ventricular function, residual myocardial ischemia, and substrates for sustained ventricular arrhythmias. Although much of the current enthusiasm in management of AMI is related to revascularization strategies, other important aspects of diagnosis and treatment should not be overlooked.