Assessment of myocardial perfusion in humans by contrast echocardiography. I. Evaluation of regional coronary reserve by peak contrast intensity.

Myocardial contrast echocardiography was performed during coronary angiography with 2 ml of sonicated meglumine diatrizoate sodium 76% (meglumine) in 40 patients (ranging in age from 25 to 79 years) before and 10 to 15 s after intracoronary injection of papaverine, 8 mg into the right coronary artery (n = 43) and 10 mg into the left (n = 46). The same protocol was repeated in 17 patients 5 to 10 min after completion of coronary angioplasty. In 13 patients with normal coronary angiograms, peak contrast intensity corrected for background myocardial intensity was measured in 36 regions and was found to increase after papaverine from 36 +/- 16 to 55 +/- 22 U (p less than 0.001). In contrast, in the 27 patients with angiographic evidence of coronary artery disease, peak intensity in 64 regions remained unchanged after papaverine (35 +/- 22 versus 36 +/- 23 U). An increase in peak intensity greater than or equal to 10 U was 80% sensitive and 92% specific for coronary artery disease. After successful coronary angioplasty, peak intensity in the involved regions improved significantly (p less than 0.001) during baseline contrast injections (from 32 +/- 16 to 50 +/- 25 U) as well as in the postpapaverine contrast injections (from 30 +/- 12 to 60 +/- 26 U). In conclusion, measurement of peak contrast intensity after intracoronary injections of sonicated meglumine provides a relative index of myocardial perfusion that allows assessment of regional coronary reserve in patients with coronary artery disease. This may be of particular value in evaluating the immediate effects of coronary angioplasty on myocardial perfusion.

Arritmias ventriculares após reperfusão coronariana. Estudo comparativo dos efeitos do verapamil e da nifedipina / Ventricular arrhythmias following coronary reperfusion. Comparative study of the effects of verapamil and nifedipine

A finalidade deste estudo foi comparar os efeitos dos antagonistas do calcio, verapamil a nifedipina, nas arritmias consequentes a reperfusao coronariana. A arteria coronaria descendente anterior foi ocluida temporariamente, durante 25 minutos, em 24 caes. Cinco minutos antes da reperfusao os animais foram randomizados em tres grupos: grupo controle (8 caes), grupo tratado com verapamil (8 caes, 0,2 mg/kg, endovenosamente, como dose de ataque seguida por 0,0l mg/kg/min) e grupo tratado com nifedipina (8 caes, 0,l mg/kg, endovenosamente, como dose de ataque sequida por 0,003 mg/kg/min). O fluxo coronario e o debito cardiaco foram determinados, atraves da tecnica de microesferas radioativas, aos 20 minutos apos a oclusao e aos 10 minutos apos a reperfusao coronariana. No grupo controle, 6 animais desenvolveram taquicardia (3 caes) ou fibrilacao ventricular (3 caes), em consequencia da reperfusao coronariana. No grupo tratado com verapamil, somente 1 animal desenvolveu fibrilacao ventricular. No grupo tratado com nifedipina, 2 animais desenvolveram taquicardia e 2, fibrilacao ventricular, o que nao foi estatisticamente diferente do grupo controle. Em conclusao, embora tanto verapamil como nifedipina sejam antagonistas do calcio, seus efeitos sao diferentes no que diz respeito as arritmias em consequencia de reperfusao coronariana