Aortic Aneurysms

Notes taken while doing some light reading on aortic aneurysms, a condition in which some segment(s) of the body’s largest artery expands following damage to the tunica intima, its innermost layer.

QTc dispersion and complex ventricular arrythmias in untreated newly presenting hypertensive patients

By Saadeh, Evans, James, and Jones || Journal of Human Hypertension (1999) Pg. 665-669

• Complications from arrythmias strongly correlate with Left Ventricular Hypertrophy (LVH)
• Testing patients using holter-monitors and 12-lead ECGs,
  • Prevalence of complex ventricular arrythmias in hypertensive patients strongly correlated to both QTc dispersion and age
  • The risk of developing complex ventricular arrythmias is significantly greater in those with hypokalaemia and LVH

Relation between QT interval variability and cardiac sympathetic activity in hypertension

By Baumert et al. || American Journal of Physiology - Heat and Circulatory Physiology (2011)

• Cross-sectional analysis indicates a correlation between cardiac norepenephrine (NE) spillover into the coronary sinus and beat-to-beat QT variability
• Patients with essential (non-secondary) hypertension had significantly higher QT variability measurements
• QT variability also correlated positively with R-R variability (P = 0.008) and systolic blood pressure (P = 0.02)
• Those with cardiovascular disease may notice a reflection of their cardiac sympathetic activation in QT readings

Hypertension and cardiac arrythmias: a review of the epidemiology, pathophysiology and clinical implicaitons

By K-H Yiu and H-F Tse || Journal of Human Hypertension (2008)

• Experimental and epidemiological studies have demonstrated a close link between hypertension and cardiac arrythmias
• Likewise, anti-hypertensive drugs (i.e., RAAS antagonists) have been shown to delay or prevent the onset of certain arrythmias

Elevated levels of short-term blood pressure variability: A marker for ascending aortic dilatation in hypertensive patients

By Argan et al. || Clinical and Experimental Hypertension

• Patients with Ascending Aortic Dilatation (Aortic Size Index ≥ 21 mm/m^2) had increased:
  • Systolic Blood Pressure
    • 24-hour (P = 0.025)
    • Daytime (P = 0.014)
    • 24-hour Coefficient of Variation (P = 0.002)
    • 24-hour Standard Deviation (P = 0.004)
    • Daytime Standard Deviation (P = 0.001)
    • Left Ventricular Mass Index (P = 0.001)
    • Left Atrium Diameter (P = 0.001)
• Greater short-term Blood Pressure Variation and Left Ventricular Mass Index were independent predictors for Ascending Aortic Dilatation in Hypertensive patients

Measurement of QT Dispersion

By P. Macfarlane || Heart by BMJ (1998) Pg. 421-423

• QT dispersion (max-min QT interval measurement) shows some promise as an indicator for multiple cardiovascular diseases
• Reliable measurement requires at least a 7-lead ECG
• A lack of measurement standards causes deviations between healthcare providers, thus limiting data on healthy ranges

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[1]: Saadeh, A., Evans, S., James, M. & Jones, J. QTc dispersion and complex ventricular arrhythmias in untreated newly presenting hypertensive patients.

[2]: Baumert, M. et al. Relation between QT interval variability and cardiac sympathetic activity in hypertension. American Journal of Physiology-Heart and Circulatory Physiology 300, H1412–H1417 (2011).

[3]: Yiu, K.-H. & Tse, H.-F. Hypertension and cardiac arrhythmias: a review of the epidemiology, pathophysiology and clinical implications. J Hum Hypertens 22, 380–388 (2008).

[4]: Argan, O. et al. Elevated levels of short-term blood pressure variability: A marker for ascending aortic dilatation in hypertensive patients. Clinical and Experimental Hypertension 43, 311–319 (2021).

[5]: Macfarlane, P. W. Measurement of QT dispersion. Heart 80, 421–423 (1998).