Re-examination of the Electrocardiogram in Boys With Duchenne Muscular Dystrophy and Correlation With Its Dilated Cardiomyopathy
ABSTRACT Duchenne muscular dystrophy (DMD) results in dilated cardiomyopathy (DC). Characteristic electrocardiographic (ECG) changes include short PR interval, right ventricular hypertrophy (RVH), prolonged QTc interval, and prominent Q waves in leads I, aVL, V5, and V6 or in leads II, III, aVF, V5, and V6. We re-examined the prevalence and correlation of ECG changes with DC in DMD. Electrograms of 115 patients with DMD were evaluated. DC was defined as an echocardiographic ejection fraction<55%. PR interval and RVH were based on age-based normal values. Abnormal Q waves were >or=4 mm. Abnormal QTc interval was >or=450 ms. ST-segment depression was defined as >0.5 mm. Fisher's exact test evaluated significant differences between groups and logistic regression determined whether number of ECG changes predicted DC. Forty had DC. No significant differences existed between the number of ECG changes in DC and non-DC groups (p=0.279). Distribution of findings included short PR interval (43%), RVH (37%), prominent Q waves in leads V5 (34%) and V6 (33%), prominent Q waves in leads I, aVL, V5, and V6 (3, 1 with DC), prominent Q waves in leads II, III, aVF, V5, and V6 (9, 4 with DC), long QTc interval (0), ST depression (2, 1 with DC), and flat/biphasic ST segments (38, 15 with DC). In conclusion, ECG changes are similar in patients with DMD regardless of presence of DC. Previously reported characteristic ECG changes are seen in a minority of DMD cases. The most common findings are short PR interval and RVH. Prominent Q waves in leads II, III, aVF, V5, and V6 are more likely.
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- "Sinus tachycardia (abnormally fast heart rate) is a prevalent arrhythmia in DMD. Short PR intervals, tall R waves, and prominent Q waves are also common impulse conduction abnormalities (Finsterer and St€ ollberger 2003; Thrush et al. 2009). In the clinic, ACE inhibitors and b-adrenergic blockade provide the mainstay of therapeutic intervention in DMD (Finsterer and St€ ollberger 2003). "
ABSTRACT: Duchenne muscular dystrophy (DMD) is a devastating and ultimately fatal disease characterized by progressive muscle wasting and weakness. DMD is caused by the absence of a functional dystrophin protein, which in turn leads to reduced expression and mislocalization of dystrophin-associated proteins including neuronal nitric oxide (NO) synthase mu (nNOSμ). Disruption of nNOSμ signaling results in muscle fatigue and unopposed sympathetic vasoconstriction during exercise, thereby increasing contraction-induced damage in dystrophin-deficient muscles. The loss of normal nNOSμ signaling during exercise is central to the vascular dysfunction proposed over 40 years ago to be an important pathogenic mechanism in DMD. Recent preclinical studies focused on circumventing defective nNOSμ signaling in dystrophic skeletal and cardiac muscle by inhibiting phosphodiesterase 5A (PDE5A) have shown promising results. This review addresses nNOS signaling in normal and dystrophin-deficient muscles and the potential of PDE5A inhibition as a therapeutic approach for the treatment of cardiovascular deficits in DMD.Handbook of experimental pharmacology 01/2011; 204(204):323-44. DOI:10.1007/978-3-642-17969-3_14
Conference Paper: Dicrotic notch detection using wavelet transform analysis[Show abstract] [Hide abstract]
ABSTRACT: The objective of this research was to devise a method of accurately and consistently extracting the dicrotic notch from the aortic blood pressure signal for various heart rates and arrhythmias. The aortic blood pressure signal has been analyzed by calculating the wavelet transform at several scales to consistently detect the temporal location of the dicrotic notch. The simultaneous locations of the peaks in the wavelet transforms of the first derivative of the aortic pressure waveform across 2 consecutive scales corresponds to the location of the dicrotic notch. A final algorithm analyzes the transform results and labels the notch point. Locating the dicrotic notch is critical for analyzing systolic time intervalEngineering in Medicine and Biology Society, 1994. Engineering Advances: New Opportunities for Biomedical Engineers. Proceedings of the 16th Annual International Conference of the IEEE; 02/1994
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ABSTRACT: The authors review wavelet based denoising methods for images that focus on statistical properties and describe a new technique which adds geometrical constraints. They apply the techniques to biomedical imagesEngineering in Medicine and Biology Society, 1994. Engineering Advances: New Opportunities for Biomedical Engineers. Proceedings of the 16th Annual International Conference of the IEEE; 02/1994