Microcatheter-Facilitated Primary Angioplasty in ST-Segment Elevation Myocardial Infarction

Background

Direct stenting is the best method for achieving reperfusion in primary percutaneous coronary intervention (PPCI). We hypothesized that the use of a microcatheter (MC) during PPCI when Thrombolysis in Myocardial Infarction (TIMI) flow ≤ 1 after wire crossing would allow visualization of the downstream artery with an optimal TIMI 3 flow at the end of the procedure.

Catheter ablation of persistent atrial fibrillation: The importance of substrate modification

Accumulating data have shown that elimination of atrial fibrillation (AF) sources should be the goal in persistent AF ablation. Pulmonary vein isolation, linear lesions and complex fractionated atrial electrograms (CFAEs) ablation have shown limited efficacy in patients with persistent AF. A combined approach using voltage, CFAEs and dominant frequency (DF) mapping may be helpful for the identification of AF sources and subsequent focal substrate modification. The fibrillatory activity is maintained by intramural reentry centered on fibrotic patches. Voltage mapping may assist in the identification of fibrotic areas. Stable rotors display the higher DF and possibly drive AF. Furthermore, the single rotor is usually consistent with organized AF electrograms without fractionation. It is therefore quite possible that rotors are located at relatively “healthy islands” within the patchy fibrosis. This is supported by the fact that high DF sites have been negatively correlated to the amount of fibrosis. CFAEs are located in areas adjacent to high DF. In conclusion, patchy fibrotic areas displaying the maximum DF along with high organization index and the lower fractionation index are potential targets of ablation. Prospective studies are required to validate the efficacy of substrate modification in left atrial ablation outcomes.     

Intrapulmonary artery balloon pulsation improves circulatory function after acute myocardial infarction in pigs

Aim: To examine whether pulmonary artery balloon pulsation (PABP) could improve circulatory function in acute myocardial infarction (AMI) in pigs. Methods/results: Ten downsize pigs were sedated and ventilated. AMI was induced by inserting a plug into the left anterior descending artery. A pulsation balloon was placed in the pulmonary artery in all animals. In the treatment group (TG), pulsations began when life-threatening arrhythmia or > 30% drop in mean blood pressure (MBP) or > 40% decrease in cardiac output compared to baseline occurred. Pulsation rate was 120/min, independent of the heartbeat, maintained for 10 min. The control group (CG) received no pulsation. In the TG (n = 5), mean BP after the AMI improved by 7 ± 12 mmHg after 150 min while in the CG, MBP decreased by 17 ± 25 mmHg, P < 0.05; coronary perfusion pressure improved by 8 ± 7 mmHg in the TG but decreased by 15 ± 12 in the CG (P < 0.05). In the CG, cardiac output did not change but in the TG it improved from 3.5 ± 0.9 after the AMI to 4.2 ± 1.1 l/min 150 min after AMI (P < 0.05). The TG required 1.8 ± 0.4 electric shocks for ventricular fibrillation versus 0.8 ± 0.4 in the pulsation group (P < 0.05). Conclusion: PABP could be useful in the management of AMI due to improved mean arterial BP, coronary perfusion pressure, cardiac output and electrical stability. The mechanism of this effect remains to be determined.     

24-hour blood pressure differences in hypertension and normotension in bed-confined subjects

This study investigates whether the degree of hypertension may be evaluated by information derived from the 24-h blood pressure (BP) curve unrelated to the pressure height. We performed 24-h BP intra-arterial monitoring in 52 bed-confined subjects (10 normotensives, 10 borderlines, and 32 hypertensives on WHO criteria). Computer analysis of 1152 BP values per subject per 24-h revealed the following: During the night hours, the percentage of the 1152 systolic BP values greater than or equal to 160 (in mmHg) increased (or did not change if 100%) in all subjects with mean 24-h systolic BP (24-h BP) greater than 170 and it decreased (or did not change if 0%) in all subjects with 24-h BP less than 150. The change in the percentage of the 1152 diastolic BP values greater than or equal to 95 during the night hours did not correlate to either the mean 24-h diastolic or systolic BP. The higher the mean 24-h systolic BP, the lower the skewness of the distribution of the 1152 systolic BP values (p less than 0.01). No such correlation existed between the skewness of the distribution of the 1152 diastolic BP values and either the mean 24-h diastolic or systolic BP. It is concluded that both the change in systolic BP during the night hours and the skewness of its distribution during the 24-h monitoring period are correlated to the severity of hypertension.     

Retrograde nontransseptal balloon mitral valvuloplasty using a modified inoue balloon catheter

Retrograde nontransseptal balloon mitral valvuloplasty, a method developed in our institution for the treatment of symptomatic mitral stenosis, avoids transseptal catheterization. Until recently, the self-positioning Inoue balloon catheter, unlike all other commercially available balloon catheters, had not been employed in this nontransseptal technique due to the short length of its catheter shaft. To employ a self-positioning balloon in retrograde nontransseptal balloon mitral valvuloplasty, we modified the Inoue device by extension of the catheter shaft. After retrograde nontransseptal left atrial catheterization using a steerable cardiac catheter, the modified Inoue balloon catheter was inserted through the femoral artery and advanced to the mitral valve retrogradely. Valvuloplasty was performed in 20 patients, with a successful result achieved in all. The modified Inoue balloon catheter was easy to use in retrograde nontransseptal balloon mitral valvuioplasty and showed excellent stability during inflation. Mean mitral valve area increased from 1.0 ± 0.29 to 2.23 ± 0.64 cm² (P<0.001) and mean transmitral gradient decreased from 11.4 ± 6 to 4.3 ± 2.1 mm Hg (P<0.001). No major or minor complications were observed. Retrograde nontransseptal balloon mitral valvuloplasty using a modified Inoue balloon catheter is a feasible and effective technique for the treatment of symtomatic mitral stenosis. It appears to combine the advantages of avoiding transseptal catheterization with the advantages of this balloon's special configuration. © Wiley-Liss, Inc.     

Blood pressure profile in patients with microvascular angina.

Normotensive patients with microvascular angina exhibit increased diastolic blood pressure and blood pressure loads during daily activities and decreased diurnal variation of systolic blood pressure, compared with age- and sex-matched normotensive controls. The abnormal blood pressure profile could play a role in the pathogenesis of microvascular angina.     

Arrhythmogenic effect of high blood pressure: some observations on its mechanism

An increase in aortic pressure is a reproducible way of causing ventricular ectopic rhythms. This study sought to determine whether it is the aortic pressure per se or the concommitant increase in afterload or preload that has a direct arrhythmogenic effect. Experiments were carried out in 17 anaesthetised dogs. For each 10 s period the pressure and the presence of a ventricular arrhythmia (at least one ectopic beat) were noted. In nine animals an aortic valve gradient was created (and released). The results were compared to those obtained by impeding the aortic flow at the ascending aorta. The mean systolic left ventricular pressure was significantly higher in the arrhythmia associated periods in 8/9 experiments when there was an aortic valve gradient and in 5/9 experiments when there was not. In 4/9 experiments the mean aortic pressure associated with arrhythmia was significantly lower with an aortic valve gradient than when there was no gradient and no arrhythmia. In 7/9 of these experiments, coronary sinus flow was measured volumetrically during the manoeuvres applied. The coronary flow was significantly lower when there was neither arrhythmia nor aortic valve gradient than when there was an arrhythmia (with or without an aortic valve gradient). In another eight experiments a pressure reservoir in the aorta was either raised or lowered while another pressure reservoir in the left atrium was moved in the opposite direction. Thus the mean aortic pressure could be increased while the left atrial pressure was decreased and vice versa. If the left atrial pressure was taken into account, the mean difference of the aortic pressure from its expected value, derived from the aortic v left atrial pressure regression equation, was significantly higher when there was an arrhythmia than it was when there was no arrhythmia in all eight experiments. On the other hand, the mean difference in the left atrial pressure from its expected value was significantly higher when there was an arrhythmia in 1/8, lower in 2/8 and not significantly different in 5/8 experiments. It is concluded that when the blood pressure is raised, it is the increase in afterload rather than an increase in aortic pressure itself or in the preload that has an arrhythmogenic effect on the ventricles.     

Transcatheter patch occlusion of perimembranous ventricular septal defects

Sixteen surgical candidates for ventricular septal defect correction were brought to the catheterization laboratory for transcatheter patch occlusion. There were 3 cases of nonrestrictive ventricular septal defects, including 2 with malalignment (tetralogy of Fallot). All patients, except those with tetralogy of Fallot who were cyanotic, had large left-right shunts. They were all corrected through the femoral vein. All defects with the exception of 2 were successfully occluded (12 full occlusions, 2 residual shunts). On follow-up, there were no embolizations, aortic insufficiency, or other complications. The method appears effective and relatively safe, and could challenge the current surgical standard of treatment.     

Use of the reversed button device to treat an atrial septal aneurysm associated with a patent foramen ovale.

An atrial septal aneurysm may be associated with a patent foramen ovale. When paradoxical emboli result, the shunt must be closed and the atrial septal aneurysm excised. A reversed buttoned occluder device was successfully used for the transcatheter treatment of this condition.