Left ventricular dysfunction during dynamic exercise in noninsulin-dependent diabetic patients with retinopathy

Area of Science:

• Cardiology
• Diabetology
• Ophthalmology

Background:

• Noninsulin-dependent diabetes mellitus (NIDDM) is a growing public health concern.
• Diabetic retinopathy is a common microvascular complication of NIDDM.
• Cardiovascular complications are prevalent in diabetic patients, even without overt clinical disease.

Purpose of the Study:

• To investigate left ventricular systolic function during exercise in NIDDM patients with and without retinopathy.
• To assess the impact of retinopathy on cardiac performance in diabetic individuals.

Main Methods:

• Systolic time intervals, including left ventricular ejection time (LVET) and preejection period (PEP), were measured using ear densitography.
• 19 middle-aged NIDDM patients (8 with retinopathy, 11 without) and 14 healthy controls underwent maximal treadmill exercise testing.
• Subjects were free of ischemic electrocardiographic responses and chest pain during exercise.

Main Results:

• At rest, no significant differences in LVET or PEP were observed between groups.
• During exercise, diabetic patients with retinopathy exhibited a prolonged LVET with a stable PEP.
• This suggests a compensatory mechanism involving enhanced ventricular filling to maintain stroke volume in this subgroup.

Conclusions:

• Diabetic retinopathy is associated with impaired left ventricular systolic function during exercise in NIDDM patients.
• Patients with retinopathy rely on increased ventricular filling to sustain cardiac output under stress.
• These findings highlight the subclinical cardiovascular impact of retinopathy in diabetes.