To evaluate the incidence, risk factors and effects of systemic hypertension on renal function and left ventricular hypertrophy after heart transplantation, 85 recipients under triple drug low low dosage immunosuppressive therapy were studied. After a mean follow-up of 12.5 +/- 8.7 months, high incidence of hypertension was observed in 67% of the patient and 71% had developed de novo hypertension. None of the pre-transplant nor post-transplant cardiovascular risk factors were significantly associated with post-transplant hypertension. Faster deterioration of renal function, as assessed by intraindividual variations of serum creatinine values, was demonstrated in hypertensive patients and appeared as an early indicator of cyclosporine nephrotoxicity in patients at risk for hypertension. [table: see text] Serial (early, intermediate, late) echocardiographic evaluations demonstrated early increase in left ventricular mass and in fractional shortening in both hypertensive and normotensive heart transplant recipients with sustained enhanced contractility in hypertensive patients. [table: see text] Further studies will help to determine the exact relationship between cyclosporine dosages and hypertension, and their respective roles in the development of renal insufficiency and left ventricular hypertrophy after heart transplantation.