Laser thrombolysis in acute myocardial infarction: results of a clinical feasibility study

Laser thrombolysis is a new, experimental, catheter based intervention aimed at selectively removing intracoronary thrombus. This first clinical study was performed to assess the feasibility and safety of laser thrombolysis, as well as its potential therapeutic place in acute myocardial infarction. Eighteen patients with acute myocardial infarction, who were either noncandidates for, or failures on, intravenous fibrinolytic therapy were included for treatment with laser thrombolysis followed by balloon angioplasty. As a result of catheter and technical failures, the laser was actually fired in only 12 patients. Improvement in TIMI flow from grade 0-1 to grade 2-3 was observed in 10 of these 12 patients after laser application. The overall results of 18 patients were: increase in TIMI grade flow from 0.33 +/- 0.49 after wire passage to 1.28 +/- 1.23 (P = 0.0051) after attempted laser application, and to 2.67 +/- 0.97 after PTCA (P = 0.0004). Two patients with previous infarctions died from left ventricular failure despite successful laser thrombolysis. One patient died during emergency bypass surgery after a failed recanalization attempt. Perforation or laser related dissection did not occur. The concept of selective laser thrombus ablation seems to be safe and feasible, but substantial improvements of the laser delivery catheters are needed. Laser thrombolysis is not an effective stand-alone therapy in acute myocardial infarction, but other possible applications warrant further research and development efforts for this potentially useful interventional tool.

Serial angioscopic and angiographic observations during the first hour after successful coronary angioplasty: a preamble to a multicenter trial addressing angioscopic markers for restenosis

Percutaneous coronary angioscopy was used in 13 patients in a pilot study to assess the intracoronary changes that occur during the first hour after balloon angioplasty (PTCA). The dilated segment was studied with 4.5F angioscopes and with quantitative coronary angiography (QCA) immediately after PTCA and at 15-minute intervals for up to 1 hour after PTCA. Significant progression of intimal dissection and thrombus formation could be demonstrated with angioscopy. These dissections and thrombi remained undetected with angiography, which only showed haziness. Thus through its superior sensitivity to intimal damage and thrombus, coronary angioscopy can reveal important intravascular events that apparently occur even after successful PTCA. The relation of such angioscopic observations to restenosis will be addressed in a subsequent multicenter study.

Late onset atrioventricular nodal tachycardia

AV nodal tachycardia may present at any age, but onset in late adulthood is considered uncommon. To evaluate whether onset of AV nodal tachycardias at older age is related to organic heart disease (possibly setting the stage for re-entry due to degenerative structural changes) 32 consecutive patients with symptomatic AV nodal tachycardia were studied. The age at onset of attacks showed a bimodal pattern, with 2 peaks: one between 15 and 35 years (22 patients) and one around 55 years (10 patients). Significantly more older patients had an underlying heart disease (60% versus 14%, P < 0.01), with coronary artery disease in 4 and hypertensive heart disease in 3. Frequent supraventricular ectopic activity was seen during baseline 24-h ambulatory monitoring in all the older patients, versus in only half of the younger patients (P = 0.005). These results indicate that late onset AV nodal tachycardia (i.e. > age 45 years) is not infrequent (33%). The frequent supraventricular arrhythmias on one hand and age-related structural AV nodal changes, potentially enhanced by underlying heart disease on the other, both may contribute to the development of late onset re-entrant AV nodal tachycardia.