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Hypoglycemic Heart- Cardiologist Perspective 245

marker of subclinical atherosclerosis and that sub- 4. Changes in heart rate variability
jects with T2DM demonstrate altered endothelial de- 5. ST-T changes
pendent and independent responses
6. Atrial fibrillation
-With type 1 DM hypoglycemia resulted in a reduction
in arterial wall stiffness and augumentation index 7. The ECG changes are primarily due to catechol-
,probably as a result of insulin induced changes in amines and hypokalemia which is the probable
the arterial endothelium mechanism for “Dead in bed syndrome”.
Hypoglycemia induced endothelial dysfunction may
act in concert with inflammatory biomarkers and MYOCARDIAL EFFECTS DUE TO
blood coagulation abnormalities to promote cardio- HYPOGLYCEMIA:
vascular events. Myocardial effects are mediated by insulin and epi-
nephrine
SYMPATHOADRENAL RESPONSES:
The following are the myocardial effects of hypogly-
- Sympathetic response to hypoglycemia represents cemia:-
a counterregulatory mechanism to diminish the
impact of abnormally low glucose levels • Ejection fraction is increased
• Peak filling rate is increased
- Release of catecholamines has profound effects
on the cardiovascular system ,directly altering car- • EDV is increased
diac contractility,myocardial work,cardiac output
and therefore oxygen demand • Prolonged severe hypoglycemia results in depres-
sion of myocardial function and causes LV dys-
- This may induce ischemia in subjects with preex- function.
isting coronary artery disease 1
- Catecholamine excess also has direct effects on HEMODYNAMIC CHANGES DUE TO
platelet reactivity and may potentially be proarryth- HYPOGLYCEMIA
mic Hemodynamic changes are primarily due to epineph-
- Hypoglycemia has been shown to significantly rine
prolong QT interval, which was an independent • Systolic BP is increased
predictor of mortality
• Diastolic BP is decreased
- There is also a significant relationship between as-
ymptomatic hypoglycemic episode and ventricular • Pulse pressure is increased
extrasystoles/nonsustained VT • Increase in central aortic pressure
- Furthermore antecedent hypoglycemia may impair • Heart rate is increased
autonomic function ,leading to reduced heart rate
variability which is an independent predictor of TRIALS HIGHLIGHTING ABOUT
poor outcomes in population with DM
HYPOGLYCEMIA AND CV EVENTS:-
- Catecholamine excess may also induce hypoka- ACCORD TRIAL :-
2
lemia and increased intracellular ca2+,this can
result in delayed afterdepolarisation ,along with • 10,250 patients
prolongation of actionpotentials by blockade of • Mean age 62, Duration of DM > 10years.
current through the human ether-a-go-go related
gene[hERG] potassium channel,all of which have • Baseline HbA1C 8-1
been implicated in the development of lethal car- • Goal <6
diac arrhythmias
• Hypoglycemia, mortality, higher in intensive group:
ECG CHANGES IN HYPOGLYCEMIA: • Rapid decrease in HbA1 (within 6months)
C
1. Prolongation of QT interval ADVANCE TRIALS :-
3
2. Tachycardia • 11,140 patients
3. Ventricular ectopic beats • Mean age 66 years

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